palaeogeography, palaeoclimatology, palaeoecology

8102019 Palaeogeography Palaeoclimatology Palaeoecology

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0 20 km

N

ArkoseRidge

LavaMtn

GrayRidge

BoxCanyon

Caribou Creek volcanic field

WillowCreek

Govrsquot Peak

Al a s k a

Fig1

Sou thern

Talkee tn

a Moun tains

Tv

Tar

Tar

Tar

Tar

Chugach subduction complex

TcTw

TcTwMa tanu

ska Valle

y

TcTw

TcTw

Tar

Fig 1 Geologic map showing Arkose Ridge Formation measured stratigraphic section locations and paleocurrent data This study focuses on Paleocene sedimentary and volcanic strataexposed north (orange-Tar) of the Castle Mountain fault at Box Canyon and to a lesser extent at Lava Mountainand Gray Ridge Abbreviations Tar mdash PaleoceneArkose Ridge FormationTcTw mdash PaleocenendashEocene Chickaloon and Wishbone Formations Tv mdash Eocene Caribou Creek volcanicRose diagrams represent structurally restored paleocurrent azimuths from Clardy (1974) Little (1988) Trop et al (2003) Cole et al (2006) and Donaghy (2012)

0 m

1 7 8 3

Arkose Ridge

Cretaceous granitoid

0 m

5 0 0

9 3 1

Jurassic granitoid

9 6 5

Gray Ridge Lava Mtn North

1770

1360

1140

844

676

378

615

257

875

1 0 m

5 0 0

1 0 0 0

1 5 0 0

5 0 0

Jurassic granitoid

5 0 0

0 m

Jurassic volcanics

Box Canyon

9 9 3

15

770

619

Conglomerate

Sandstone

MudstoneShale

Covered Interval

Lava

T u f f

Explanation


Willow Creek

0 m

1 5 0

3 0 0

4 6 7

265

170

West East

Q

n = 208 n = 421 n = 780 n = 1140N = 2 N = 4 N = 7 N = 11

n=707

N=7

Lava sample for ArAr age

Tuff sample for UPb age

SS sample for UPb zircon age

1

2

2

1

Bivalve fossil

Palm fossils

FossilQuarry

volcanic plutonic

meta-morphic

other

conglomerate clast types

Fig 2 Generalizedlogs (inmeters) of measured stratigraphic sectionsof Paleocene sedimentary andvolcanic strataexposedin thesouthern Talkeetna Mountains (seeFig1)Tuffages areUPb zircon analyses whereas lava ages are 40Ar39Ar analyses on groundmass n = total number of clasts counted N = number of conglomerate beds sampledIsotopic ages from tuff and lava are from Idleman et al (2011) Squares mark position of sandstone samples for detrital geochronologic ages reported by Kortyna et al (2013) that yield

maximum depositional ages consistent with the tuff and lava ages Pie diagrams above sections show summary of conglomerate clast compositions reported by Kortyna et al (2013)

58 D Sunderlin et al Palaeogeography Palaeoclimatology Palaeoecology 401 (2014) 57 ndash80



The present study reports on the paleobiological record containedwithin the essentially unexplored 1047298uvialndashlacustrine depositional suc-cession of the Late PaleocenendashEarly Eocene Arkose Ridge Formation of south-central AlaskaIncluded hereare the1047297rstanalyses of theunits re-cently discovered well-preserved fossils of plants bivalves and 1047297shthat indicate the presence of a diverse terrestrial ecosystem in south-central Alaska during Late PaleocenendashEarly Eocene time Togetherwith new sedimentologic and geochronologic data this paper provides

a glimpse into Paleocenendash

Eocene sub-polar depositional processesecology and climate Similar recent studies in other PaleocenendashEocenestrata exposed in south-central Alaska permit regional integration of paleo1047298oristic paleoclimate and paleoenvironmental data (eg Parrishet al 2010 Williams et al 2010 Sunderlin et al 2011) in addressingissues of critical importance to the depositional climatic ecologicaland tectonic evolution of the northern North American Cordillera dur-ing early Paleogene time

2 Geologic background

Southern Alaska consists of a complex collage of Mesozoic andCenozoic exhumed and active sedimentary basins accreted terranesmagmatic belts and accretionary prism strata (eg Plafker and Berg1994 Trop and Ridgway 2007) A ~4 km thick succession of Jurassicto Eocene sedimentary strata exposed in the southern TalkeetnaMountains Matanuska Valley and northern Chugach Mountains of interior south-centralAlaskarecords changes in convergent margin tec-tonic processes as well as paleoenvironments of deposition The ArkoseRidge Formation the focus of this report is exposed in a ~20 ndash70 kmwide ~90 km long eastndashwest-trending outcrop belt in the southernTalkeetna Mountains (Fig 1) The strata formed in a remnant forearcbasin between remnant magmatic arc plutons and a coeval slab-window volcanic 1047297eld to the north and a coeval accretionary prism tothe south (Cole et al 2006 Ridgway et al 2012) Forearc basin strataexposed south of the Castle Mountain fault in the Matanuska Valleyand northern Chugach Mountains are mapped as the Chickaloon andWishbone Formations (Winkler 1992) These forearc strata have been

shuf 1047298ed laterally by several tens of kilometers of strike-slip displace-ment along the fault (Fuchs 1980 Winkler 1992 Szwarc et al 2011)Arkose Ridge Formation strata crop out north of the Castle Mountainfault where they overlie JurassicndashPaleocene arc plutons and marineforearc basin strata along an unconformity characterized by tens tohundreds of meters of topographic relief The Arkose Ridge Formationstrata exhibit maximum preserved thicknesses up to 2000 m and locallyinter1047297nger with volcanic strata of the Caribou Creek volcanic 1047297eld(Fig 1 Cole et al 2006) Deposition of the Arkose Ridge Formation oc-curred during Late Paleocene time based on 604 to 565 Ma UPb zirconages from tuffs and the youngest clusters of UPb detrital zircon ages insandstone (Idleman et al 2011 Kortyna 2011 Donaghy 2012)

The precise paleolatitude of the Arkose Ridge Formation at the timeof Paleogene deposition is not well constrained Paleomagnetic results

from sedimentary strata of the Chickaloon and Arkose Ridge Formationssuggest that deposition occurred 400 to 2800 km south of their presentlatitude (~62degN) (Stamatakos et al 1988 1989) Howeverthese resultsmay be impacted by inclination shallowing attributable to post-depositional compaction of the texturally immature sampled clasticstrata (eg Kent and Irving 2010) Paleomagnetic data from coeval toslightly younger Late PaleocenendashEarly Eocene Caribou Creek volcanicrocks in the southern Talkeetna Mountains (Hillhouse et al 1985Panuska et al 1990 Hillhouse and Coe 1994) do not indicate signi1047297-cant northward displacement since ca 55ndash50 Ma Based on regionalgeologic relations and the presently available paleomagnetic data Coleet al (2006) infer no more than 200 to 500 km of northward translationof the basins strata since ca 57 Ma The Arkose Ridge Formation andoverlying volcanic succession were uplifted and deformed during

Neogene time The present study takes advantage of exceptionally

well preserved stratigraphic successions exposed in alpine cirques inthe uplifted region

Recent studies provide a stratigraphic framework for the ArkoseRidge Formation that is summarized in Fig 2 The formation comprisesup to 2000 m of siliciclastic and volcanic strata that accumulated inalluvial 1047298uvial and lacustrine environments of deposition (Trop et al2003 Kassab et al 2009 Kortyna et al 2009 Donaghy et al 2011)The dominance of southward-directed paleo1047298ow indicators (Fig 1)

together with 85ndash

55 Ma detrital zircons in sandstone and volcanicndash

plutonic clasts in conglomerate indicates that detritus was erodedmainly from CretaceousndashPaleocene igneous source terranes exposednorth of the outcrop belt (Fig 1 Kortyna 2011 Donaghy 2012Kortyna et al 2013) Western stratigraphic sections at Willow CreekArkose Ridge and Lava Mountain are characterized by boulder con-glomerate cross-strati1047297ed sandstone and carbonaceous mudstonewith poorly-preserved leaf compressions interpreted as the depositsof gravelly braided streams sandy anastomosing 1047298uvial systems withvegetated 1047298oodplains small 1047298oodplain lakes and tidally in1047298uencedstreams Sparse lava and tuff interbeds indicate that 1047298uvialndashlacustrine

VA-volcanic facies association

SA-sandy facies association

MA-muddy facies association

GA-gravelly facies association

Fig 3 Geologic mapof BoxCanyonstudyarea showing lithofaciesdistributions measuredstratigraphicsection reported here (BOX1)geochronologysample locations and the loca-tion of the fossil quarry

Geology modi1047297ed from Winkler (1992) based on mapping carried out during this study

59D Sunderlin et al Palaeogeography Palaeoclimatology Palaeoecology 401 (2014) 57 ndash80



Explanation

g c b

0m

25

50

75

100

125

150

175

200

225

250

275

300

400

325

350

375

500

425

450

475

525

550

GcmSm

Gcmi

Gcm

Gcm

Gcmi

Gcmi

Gcm

Gcm

Gcm

Gmm

GmmSm

GmmSm

ShSr

GcmGcmi

GcmSmFsc

GcmGcm

GcmGmmSmSh

SmStShSm

StSmSh

SmSh

SmSh

SmSrFsm

GcmSm

SmSr

StSm

Gcmi

Gcm

Gmm

Gmm

Fsm

SmSh

SmStGcmGmm

FscSmGcmiGcm

Gmm

SmSh

SmStSpFscFsm

SmSt

SmSrSt

FmmFsc

FscStSr

SrSlSt

Fsc

St

SmStSh

pf m vc

575

600

625

650

675

700

FscFmm

StSm

GcmGcmSt

StSmSpGcm

ShSmFsmFsl

Sm

StFsm

St

Gcm

725

750

775

800

Tuff

993

StFsmFsl

StSm

Tuff

TuffSt

Sm St Fsm

Lavas

Sm St

Poorlyexposedinterval

Lavas

Lavas

525

550

FmmFsc

FscStSr

SrShSt

Fsc

St

SmStSh

500

g c bpf m vc

Q

ArAr lava sample

UPb tuff sample

UPb ss sample

Fishplant fossil quarry

Fossil leaves

Fossil branches

GA

GA

VA

MA

MA

MA

SA

2

1

Q

N61 58658rsquoW148 15998rsquo

GA

top eroded

Jurassic volcanic rocks

s - siltstonetuff

f - fine sandtuff

cs - coarse sandtuff

g - granulelapilli

c - cobblelapilli

b - boulderblock

s g cf cs b

Grain SizeConglomerate (Gcm Gmm Gcmi)

Sandstone (Sm St Sp Sr Sh Smv)

Siltstoneshale (Fsc Fsm Fsl Fmm)

Tuff bentonite tuffaceous siltstone

Andesite and basalt lava flows

Covered Interval

Carbonaceous debris

Fish fossils

Horizontal stratification

Cross-stratificationscours

Granule-pebble lags

Columar joints

VA - Volcanic association MA - Muddy fluvial-lacustrine assocSA - Sandy fluvial association GA - Gravelly fluvial association

072609CDK2

10AK20

2 10AK17

10AK17

210AK20

072609CDK2

Fig 4 Simpli1047297ed log (in meters) of measured stratigraphic section at Box Canyon Note fossil quarry located 643m above the base of the sectionthe primary collecting sitefor plant and1047297sh fossils described in this report Refer to Fig 3 for location of section (BOX1) Table 1 for explanation of lithofacies abbreviations and Fig7 for detailed section spanning fossil quarry




environments were occasionally in1047298uenced by volcanic processes East-ern strata exposed at Gray Ridge consist chie1047298y of conglomerate cross-strati1047297ed sandstone carbonaceous siltstone tuff-breccia lapilli tuffcrystalline tuff pyroclastic1047298ow deposits and sparse lavas that represent1047298uvialndashlacustrine environments routinely in1047298uenced by pyroclasticeruptions No detailed paleoenvironmental analyses of the easternmostoutcrops of Arkose Ridge Formation at Box Canyon havebeenpublishedto date Previous studies are limited to a generalized measured section

reported by Trop et al (2003) and regional-scale geologic mapping(1250000 scale by Winkler 1992) Geochronologic data from BoxCanyon are limited to one low-precision KndashAr age from the volcanicsuccession that overlies the Arkose Ridge Formation (Silberman and

Grantz 1984) and one ArndashAr age from a granitic clast in conglomerate(Trop et al 2003)

Published paleobiological data from the Arkose Ridge Formation aresparse Plant fossil remains have been reported as occurring within theunit (Martin and Katz 1912) but little taxonomic or taphonomic infor-mation is published No faunal body fossils have been reported previ-ously from the Arkose Ridge Formation Recent stratigraphic andpaleontologic studies of the Chickaloon Formation in the Matanuska

Valley (Neff et al 2011 Sunderlin et al 2011) provide information onthe Early Eocene paleoecology and paleoclimate of the Matanuska Val-leyndashTalkeetna Mountains forearc basin Upper Chickaloon strata containa diverse assemblageof broadleaf dicot taxa along with Metasequoia and

A B

C D

E F

JTrt

JTrt

Gcm

Gcm

St

Sh

Sm

GA

MA

Q

Fsm

St

Fig 5 Photographs showing key stratigraphicrelationships at Box Canyon Black tadpolesymbols denote bedding (A) Unconformity between orange-weatheringJurassic volcanicrocks(JTrt)and overlying Paleocene sedimentary andvolcanic successionWhite arrows mark unconformity Redline markslocation of measuredsectionBOX1(Figs2 and 4) (B) Amalgamatedlenticularconglomerate beds(GA) overlainby fossil quarry (Q) in mudstone association (MA) People forscale (whitearrow) (C) Close-upof amalgamated pebblendashcobble conglomerateandsparsesandstone (arrows) of conglomerate association (D)Clast imbrication in pebblendashcobble conglomerate of thegravelly 1047298uvial association Solid black bar on scale is 10 cmlong(E) Massive sandstone (Sm) and pebblendashcobble conglomerate (Gcm) of gravelly 1047298uvial association Hammer (lower center circled) for scale (F) Horizontally strati1047297ed sandstone (Sh)trough cross-strati1047297ed sandstone (St) and siltstone of sandy 1047298uvial association Person (upper center circled) for scale (G) Lenticular beds of amalgamated massive to cross-strati1047297edsandstone of sandy 1047298uvial association White arrows mark cross-strati1047297cation Hammer (right center circled) for scale (H) Fine-grained massive to ripple cross-strati1047297ed sandstoneand siltstone of sandy 1047298uvial association Hammer for scale (I) Carbonaceous mudstone intervals characteristic of muddy 1047298uvialndashlacustrine association (MA) Black line marks contactwith overlying gravelly1047298uvial association (GA) Exposure is approximately125 m tall (J)Close-up of thin-bedded carbonaceous shale (Fsc) andbentoniteHammerfor scale (K)Angularunconformity between sedimentary succession andlavas of the overlying volcanicsuccession(VA) Sedimentarysection is dominated by muddy 1047298uvialndashlacustrine association (MA) withminor lenticular beds of conglomerate (white arrows) Exposure is approximately 220 m tall (L) Thick-bedded ma1047297c lavas of the volcanic succession Jacob staff (15 m) for scale (lower

right)




other conifer shoots and trunks compressions of a diverse suite of seeds monocotyledonous aquaticsemi-aquatic plants and inclusion-bearing dispersed amber (Sunderlin et al 2011) Chickaloon redwoodforests grew quickly in water-saturated mires based on taphonomicanalyses of buried cupressaceous conifer trees (Williams et al 2010)

Fauna in the Chickaloon1047298oodbasin deposits include the freshwater gas-tropod genera Campeloma and Bellamya (Viviparidae) (Wolfe et al1966 Walker 2009) poorly-preserved unionid bivalves and a solitaryoccurrence of a chelydrid turtle carapace (Hutchison and Pasch 2004)Further to the west fossil plants are also reported from the newly-named Ketavik Formation on the Alaska Peninsula in Katmai NationalPark (Parrish et al 2010) There a Paleogene 1047298uvial succession domi-nated by conglomerates and sandstones was sourced by debris 1047298owsand paleo-valley deposition off of the adjacent Jurassic Talkeetna For-mation Leaf and wood fossilsare preservedin thin mudrock facies asso-ciations in this succession along with evidence of early pedogenesisDicot leafmorphotyperichnessis relatively high for thissmall collection(12 morphotypes in 45 specimens) and together with wood growthring analysis suggests a warm temperate paleoenvironment (Parrish

et al 2010)

This paper reports on stratigraphically constrained collections of plant fossils made from the Arkose Ridge Formation on the western1047298ank of an unnamed hillslope in the area known locally as Box Canyonin the southern TalkeetnaMountains between the Chickaloon River andEast Boulder Creek (Fig 3) Continuous bedrock exposures on the west-

facing hillslope reveal approximately 3000 m of eastndashwest lateral expo-sure and as much as 1000 m of verticalsection Geologic mapping in thearea documents several faults that displace marker beds up to severaltensof meters but the entire stratigraphic succession is relatively unde-formed and well-exposed (Fig 3)

3 Box Canyon sedimentology amp stratigraphy

A reference section was measured at Box Canyon to help integratesedimentological paleobotanical and geochronological data (BOX1on Figs 3 4) The base of the section is a prominent unconformity sep-arating basal conglomerateof the Arkose Ridge Formation from orange-weathering volcanic rocks of the Jurassic Talkeetna Formation (Fig 5A)Thetop of thesection is markedby theuppermost exposure of a N200m

thick succession of Paleogene ma1047297c-intermediate lavas at the top of the

G H

I J

K L

VA

MA

Bentonite

Fsc

Fsc

MA

GA

Fig 5 (continued)




ridgeline (SHEER USGS benchmark in Fig 3) A prominent angular un-conformity separates the Arkose Ridge Formation from these overlyinglavas

Individual beds were measured at a centimeter scale using a Jacobstaff Lithologies were denoted in termsof grain size sedimentary struc-tures fossil content bed geometry and the nature of the bed contactsThe lithofacies documented in the 1047297eld have been widely reported inthe literature Table 1 describes 15 individual lithofacies thatare present

in the measuredstratigraphy and includestheir correspondingstandardinterpretations of physical processes and depositional systems Key fea-tures are shown within measured sectionsin Figs 24 and 7 and photo-graphs in Fig 5 Additional lithofacies photographs are available in thesupplemental material online Individual lithofacies are commonly in-terbedded with each other in four associations (ie lithofacies associa-tions) that are described below

31 Gravelly 1047298uvial association

311 Description

The gravelly1047298uvialassociation makes up the lower 310 m of theBoxCanyon section as well as several intervals in the upper third of the sec-tion (Figs 4 6A) Representative photographs are shown in Fig 5AndashEImbricated horizontally strati1047297ed (lithofacies Gcm Gcmi) and large-

scale cross-strati1047297ed (Gcp) pebblendashcobble conglomerate are the mostabundant lithofacies Subordinate massive to horizontally strati1047297edsandstone and siltstone (Sm Sh Fsm) occur in laterally discontinuousinterbeds that are typically ~20ndash50cm thickand~ 3ndash8 m wide Shallowerosional scours are common and individual genetic packages of con-glomerate are laterally discontinuous over several meters to N15 mand are typically N 05ndash3 m thick deposits are typically amalgamatedinto 10ndash25 m thick successions Sub-rounded to rounded clasts in con-

glomerate are moderately sorted and contained in medium to coarse-grained volcanic-lithic sandstone Sandstones contain fragmentedcoali1047297ed plant fossils Conglomerates are dominated by felsic granitoidand ma1047297c-intermediate volcanic clasts

312 Interpretation

This association is typical of coarse-grained gravelly braided streamdeposits including longitudinal bar and bar-1047298ank deposits and cross-strati1047297ed channel axis deposits (egSmith 1974 Hein and Walker1977 Lunt and Bridge 2004) The moderate degree of clast sortingrounding and lack of poorly-sorted bouldery mass 1047298ow deposits indi-cates that braided streams formed within alluvial plain distal stream-dominated alluvial fan or fan-delta environments (eg Ridgway andDeCelles 1993) as opposed to proximal stream-dominated alluvialfans

Table 1

Lithofacies characteristics and interpretations for Arkose Ridge Formation strata at Box Canyon

Facies Color bedding texture structures fossils Facies interpretations

Gmm Massive granule to cobble conglomerate with sparse boulders poorly tomoderately sorted subangular to rounded clasts matrix supported with1047297ne- to medium-grained sandstone matrix unstrati1047297ed

Debris 1047298ow and hyperconcentrated 1047298ood 1047298ow in shallow braided channelsand bar-tops (Pierson and Scott 1985 Smith 1986)

Gcm Massive granulendashpebblendashcobble conglomerate with moderately sortedsubangular to rounded clasts clast-supported with medium- tocoarse-grained sandstone matrix unstrati1047297ed to crudely horizontallystrati1047297ed with scours

Deposition by traction currents in unsteady stream-1047298ow and high-concentration1047298ood-1047298ow in shallow braided channels and bar-tops (Pierson and Scott 1985Smith 1986)

Gcmi Imbricated pebblendashcobble conglomerate with moderately to well sortedsubangular to rounded clasts clast-supported with medium- to

coarse-grained sandstone matrix unstrati1047297ed to crudely horizontallystrati1047297ed

Deposition by traction currents in unsteady stream-1047298ow and high-concentration1047298ood-1047298ow in shallow braided channels and bar tops (Miall 1978 Collinson 1996)

Gcp Planar cross-strati1047297ed pebblendashcobble conglomerate moderately to wellsorted subangular to rounded clasts clast-supported with medium- tocoarse-grained sandstone matrix

Deposition by large straight-crested gravelly ripples and dunes under traction1047298ows in shallow 1047298uvial channels gravel bars and gravelly Gilbert-type deltas

Sm Gray to tan 1047297ne- to coarse-grained massive sandstone with thingranulendashpebble stringers plant debris and petri1047297ed to coali1047297ed woodtuffaceous or calcareous matrix locally medium to thick bedded

Stream-1047298ow and high-concentration 1047298ood-1047298ow in shallow channels and bar topsand crevasse splay (Miall 1978 Collinson 1996

Sh Gray to tan 1047297ne- to coarse-grained plane-parallel laminated sandstonewith plant debris and petri1047297ed to coali1047297ed wood tuffaceous or calcareousmatrix locally medium to thick bedded

Deposition under upper plane bed conditions from very shallow or strong (N1 ms)unidirectional 1047298ow conditions in 1047298uvial channels bar tops crevasse channels andsheet1047298oods (Miall 1978)

Sp Gray to tan 1047297ne- to coarse-grained planar cross-strati1047297ed sandstone withthin granule-pebble stringers plant debris and petri1047297ed to coali1047297ed woodtuffaceous or calcareous matrix locally medium- to thick-bedded

Migration of 2D ripples and small dunes under moderately strong (~40ndash60 cms)unidirectional channelized 1047298ow in 1047298uvial channels bar tops crevasse channels(Miall 1978)

St Gray to tan 1047297ne- to coarse-grained trough-cross-strati1047297ed sandstone withthin granulendashpebble stringers plant debris and petri1047297ed to coali1047297ed woodtuffaceous or calcareous matrix locally medium- to thick-bedded

Migration of 3D ripples and dunes under moderately strong (40ndash100 cms)unidirectional channelized 1047298ow in 1047298uvial channels bar tops crevasse channels(Miall 1978)

Sr Gray to tan 1047297

ne- to medium-grained sandstone with asymmetric 2D and 3Dcurrent ripples thin- to medium-bedded Migration of 2D and 3D ripples under weak (20ndash

40 cms) unidirectional 1047298

ow inshallow 1047298uvial channels bar tops crevasse channels and lake margins (Miall 1978)Smv White to tan tuffaceous sandstone with subangular to subrounded pumice

and tuff clasts and fragmented organic matter contained in white to tantuffaceous matrix massive to horizontal strati1047297ed

Reworking of tephra and non-volcanic detritus by stream 1047298ow and 1047298ood 1047298ow(Fisher and Schmicke 1984 Smith 1986 1987)

Fsm Green gray blue-gray brown and reddish brown mudstone and tuffaceousmudstone with fragmented plant fossils coali1047297ed wood fragments roottraces sparse evidence of pedogenesis mainly mottling and bioturbation

Suspension fallout tephra fallout and pedogenesis in poorly drained vegetated1047298oodplains (Collinson 1996 Miall 2006 Melchor 2007)

Fsl Gray purple and green-gray laminated siltstone with algal laminae anddelicately preserved 1047297sh and plant fossils including diverse leaves stemsand seeds

Subaqueous suspension settling in low-energy ponds or lakes ( Johnson andGraham 2004 Pietras and Carroll 2006)

Fsc Black carbonaceous mudstone with lignite stringers plant leaf matscomminuted plant debris coali1047297ed to petri1047297ed wood fragments and sparseroot traces

Suspension settling and accretion of organic matter and clastic mud in poorlydrained 1047298oodplains including small bogs fens moors muskegs or swamps(McCabe 1984 1991)

Coal Blocky lignite shaley coal and coali1047297ed organic debris Vertical accretion and diagenesis of organic matter in poorly drained bogs fensmoors muskegs or swamps McCabe 1984 1991)

Vt White tan and blue-green vitric-crystal tuff and bentonite with subangularframework grains of pumice feldspar and quartz and fragmented plant debris

Pyroclastic fallout deposition and incipient pedogenic modi1047297cation mainly in1047298oodplain swamps ponds and lakes (Cas and Wright 1987)




32 Sandy 1047298uvial association

321 Description

The sandy 1047298uvial association comprises the interval 310ndash425 m

above the base of the Box Canyon section (Figs 4 6B) Representativephotographs are shown in Fig 5FndashH Strata are chie1047298y massive tocross-strati1047297ed sandstone (lithofacies Sm Sp St Sr) as well as subordi-nate volcaniclastic sandstone (Smv) and siltstone (FsmFsc) Amalgam-ated packages of lenticular sandstone with scours characterize thesuccession Internally individual sandstone units are typically 02ndash05m thick and laterally discontinuous over 10ndash25 m Coali1047297ed or poorlypermineralized woody debris and poorly-preserved leaf compressionsare common Sub-rounded clasts of pumice are abundant in sandstonelocally

322 Interpretation

This association re1047298ects stream1047298ow and episodic 1047298ood 1047298ow in shal-

low channels and bar tops in 1047298uvial channels and to a lesser extent

suspension fallout on bar-tops and 1047298oodplains (Miall 2006) Evidencefor 1047298uvial bedload deposition includes cross-strati1047297cation erosive bedbases scours upward 1047297ning trends and lenticular bed geometries Bartops and adjacent 1047298oodplains were forested judging by the presence

of plant fossils in this lithofacies association Volcaniclastic sandstoneswith rounded pumice grains record proximal reworking of tephraby 1047298uvial processes The absence of evidence for lateral accretion andlevee development (eg thick rippled siltstones and crevasse splay de-posits) suggests that these were uncon1047297ned shallow braided 1047298uvialsystems (Smith 1974 Lunt and Bridge 2004)

33 Muddy 1047298uvialndashlacustrine association

331 Description

The muddy 1047298uvialndashlacustrine association makes up the majority of the interval 450ndash775 m above the base of the Box Canyon section(Figs 4 6C) This association is characterized by diverse lithofaciesincluding chie1047298y Fsc Fsl Fsm Vt and coal with subordinate Sm St

Sp Smv Gcm and Gcmi (Figs 5Indash J 6C) These strata contain abundant

335

340

345

350

355

360

365

370

375

380

SmStSpSh

Sh

SmStSh

ShSm

Sm

ShSm

StSmShSm

SmSh

FslFscSh

Sh

SmSh

Fsc

Smv

SmFsc

SmShSmv

s g cbf c

50

55

60

65

70

75

80

85

90

95

100

Gcmi

Gcmi

(174 cm)

Gcm

Gcm

(124 cm)

Gcmi

(135 cm)

s g cbf c

500

505

510

515

520

525

530

535

540

545

550

s g cbf c

SmSrSt

FmmFsc

Sm

StSr

Fsc

Fsc

FscCoal

St

Fsc

Gcm

Gcm

Gcm

Gcm

GcmSm

Sm

Gcm

Gcm

Sm

Covered

Fsc

FscCoal

St

A B C

St

Fsc

Fsc

tuffaceous

SrSt

Fig 6 Representativedetailed logs (in meters)showing gravelly1047298uvial (A)sandy1047298uvial association (B) andmuddy1047298uvialndashlacustrineassociation (C)at BoxCanyon (BOX1)Referto Fig4for explanation of symbols and patterns and Table 1 for explanation of lithofacies abbreviations




plant fossil remains including poorly- to well-preserved leaf compres-sions and larger organic material such as coali1047297ed permineralized andimpression fossils of herbaceous axes and logs Evidence for periodicallylower water tables such as desiccation cracks are rare The associationincludes prominent packages composed of imbricated conglomeratecross-strati1047297ed sandstone and laminated to carbonaceous siltstone con-taining delicately preserved 1047297sh fossils and plant remains Siltstones lo-cally exhibit rhythmic laminae with distinct variations in grain size

color and organic content Sparse thin-bedded coals are present locally(Fig 5 J) Evidence for limited pedogenesis includes sparse rootlets andmottling

332 Interpretation

Thisassociationis interpreted as the depositsof lacustrine fan deltasvegetated 1047298oodplains open lakesponds and miresswamps Packagesof laminated mudstone sandstone and conglomerate were depositedby gravelly braidedrivers andopen lakes andponds The conglomeraticportions of the packages exhibit lithofacies that are consistent with de-position by shallow braided 1047298uvial channels which may have formedthe distal portions of stream-dominated alluvial fans that progradedinto lakesponds (eg Ridgway and DeCelles 1993) Vegetated 1047298ood-plains accumulated abundant organic material Lacustrine transgressiveevents are marked by sharp upper surfaces on the conglomerateswhich are overlain by sandstone and green-gray laminated profundalsiltstone Deposition of laminated siltstone took place as lake levels con-tinued to rise Rhythmic laminae re1047298ect seasonal 1047298uctuations in lacus-trine depositional conditions and may be interpreted as varves Highwater tables and frequent disruption by renewed deposition evidentlyinhibited advanced pedogenesis in 1047298oodplain deposits

34 Volcanic association

341 Description

The volcanic association characterizes the upper 215 m of the BoxCanyon section (Figs 2 4 5KndashL) This succession of unnamed volcanicstrata can be traced northeastward into a 1000 m thick volcanic succes-sion documented in detail by Cole et al (2006) and referred to as the

Caribou Creek volcanic 1047297eld (Fig 1) At Box Canyon the volcanic strataare chie1047298y 1047297ne-grained basalt and intermediate lavas The basalts con-sist chie1047298y of olivine pyroxene and plagioclase Intermediate lavas in-clude basaltic andesite and andesite that consist mostly of plagioclaseand generally contain sparse pyroxene Most 1047298ow units are 3ndash7 mthick with massive bases and vesicular or amygdaloidal tops

342 Interpretation

This association re1047298ects effusive subaerial eruptions deposited upondeformed sedimentary deposits of the Arkose Ridge Formation Thethick succession of primary 1047298ow deposits suggests deposition proximalto the 1047298anks of an active volcanic edi1047297ce Evidence for deposition undersubaqueous conditions such as pillow structures peperites andhyaloclastites has not been recognized We postulate that magmas like-

ly erupted as 1047297ssure eruptions along northwest-striking normal faultsexposed in the Caribou Creek volcanic 1047297eld The normal faults havebeen attributable previously to crustal extension associated withright-lateral simple shear along the Castle MountainndashCaribou fault sys-tem (Grantz 1966 Cole et al 2006) Detailed geochemical and petro-logic studies are needed to fully characterize the volcanology andpetrogenesis of the lavas

35 Stratigraphic summary

The Paleogene strata exposed at Box Canyon represent an overallupward-1047297ning succession from gravelly braided 1047298uvial deposits tosandy 1047298uvial deposits to muddy 1047298uvialndashlacustrine deposits withminor gravelly 1047298uvial deposits Numerous abrupt changes in lithology

and incorporated1047298oral remainsimply transitory habitats and vegetation

stands in a rapidly aggrading landscape of shallow streamslakes pondsand swamps Up-section lithofacies transitions re1047298ect enhanced 1047298ood-plainndashlacustrine deposition in standing water together with enhancedvolcanic deposition and erosion of volcanic detritus from the nearbyCaribou Creek volcanic 1047297eld Progradation of the volcanic 1047297eld resultedin deposition of a volcanic succession of chie1047298y lavas upon the sedimen-tary succession following an episode of deformation basin uplift anderosion

4 Fossil collections

Fossil 1047298oral and faunal remains are reported chie1047298y from a quarryinto a richly fossiliferous horizon at Box Canyon (Figs 2ndash4) The collec-tion bedis laterally discontinuous over 10 m and maximally 13m thicka localized horizon within the muddy 1047298uvialndashlacustrine lithofacies asso-ciation described above 643 m above the base of the measured sectionInternally light to dark gray laminated siltstonesclaystones comprisemost of the stratal thickness of the quarry (FsmFsl) and regularly re-peating claystonesiltstone laminations suggest cyclic sedimentationconsistent with varved lacustrine deposits This 1047297ne-grained successionimmediately overlies a moderately-sorted coarse tan sandstone withcoali1047297ed woody fragments and comminuted plant debris (ShSm)(Fig 7) A patchy distribution of organic and iron carbonate stainingon the top surfaces of the mudrock varves are interpreted as evidence

Arbitrary Base

10 cm

20 cm

30 cm

40 cm

50 cm

60 cm

70 cm

coarsesandstone

1-5 cm coalified

wood fragments

laminated graysiltstone

fossil seeds

leaves

purplebrown mottled

claystone

heavily weathered

gray regularly-laminated

siltstone varves

microbial horizons

fossil seeds leaves fish

soil at quarry top

Clay Silt Sand

Fig 7 Detailedstratigraphic log (in cm)of the fossil quarry interval at Box Canyon Greenleaf and fossil1047297sh symbol at most fossiliferous horizons Wavy symbolsindicate evidence

of microbial activity on mudrock parting surfaces




of microbial 1047297lms developed during phases of reduced sediment inputThe BoxCanyon paleo1047298ora and paleofauna reportedhere is a compositecollection through ~70 cm (Fig 7) andacross theextent of its accessiblelateral exposure Compressionndashimpression fossils are preserved bothwithin andat thecontacts of these layersnever at angles to thelaminaeMore than 500 foliar axis and reproductive organ specimens as well asthree 1047297sh skeletal impressions were excavated from the Box Canyonquarry We also report here on fossil plant and bivalve remains from

Gray Ridge (Figs 1 and 2) All plant and bivalve fossils are accessionedinto the collections of The Museum of the North at the University of AlaskaFairbanks(UAM 2012023ESCI) The 1047297sh remains are also curat-ed within the collections at The Museum of the North at the Universityof Alaska Fairbanks (UAMES 32075)

41 Paleo 1047298oral elements

The dicot leaf assemblage at the Box Canyon quarry is diverse consid-ering the size of the obtained collection (n = 126 half to full leaves) andthe limited lateral extent of the lacustrine deposits in which it is pre-served Twenty dicot leaf morphotypes (Fig 8) were recognized and de-scribed accordingto standard methods (Ellis et al 2009) When possiblemorphotypes were assigned to genera andspecies based on comparisonswith published descriptions of similar-age leaf assemblages from Alaska(Hollick 1936 Wolfe 1966 1977 Wolfe et al 1966 Parrish et al 2010Sunderlin et al 2011) and elsewhere on North America (eg Hickey1977) In many casesthese assignments are tentative and where no con-1047297dent taxonomic assignment was possible we simply note the dicot leaf

form as a distinct morphotype (X1 X2 etc) Zizyphoides 1047298abella

Newberry and ldquo Ampelopsisrdquo acerifolia Wang() are the most abun-dant forms together comprising ~25 of the recovered specimensat the Box Canyon quarry Among the less abundant forms we recog-nize Chaetoptelea microphylla Newberry Meliosma longifolia HeerCercidiphyllum sp Siebold amp Zuccarini Lamanonia sp Vellozo and Mag-

nolia ovata A St-Hil in addition to thirteen unassigned morphotypesX1ndashX9 and X11ndashX14 including cf Platycarya Siebold amp Zuccarini (X2)

cf Nyssa Linnaeus(X4) and cf Corylites Gardner (X7) (Fig 8)Someun-assigned taxa are similar (X2 X5 and X8) but are split into separatemorphotypes based on aspects of the preserved venation and margincharacter See Appendix A for images and descriptions

The non-dicot paleo1047298oral assemblage at the Box Canyon quarry wascollected to maximizethe recovered diversity Multiple compressions of the monocot Sparganium parvum were collected The taxons in1047298ores-cences are often found in isolation but one specimen preserves themin association with the foliar blade (Fig 9A) Winged samaras similarto Paleosecuridaca (Pigg et al 2008) (Fig 9B C) many intact andfragmentary specimens of Cruciptera (Fig 9D) and Macginicarpa acatkin (Fig 9E) three unidenti1047297ed fruits (Fig 9FndashH) and a Picea seed(Fig 9I) were also among the preserved reproductive organs Metase-

quoia shoots occur in abundance at Box Canyon not only within themudrocks of the sample quarry but also within many beds of themuddy 1047298uvialndashlacustrine lithofacies association through the entiremeasured section (Fig 4) Pollen cones and shoots of Metasequoia

(Fig 9 J) are well-preserved in the study quarry along with Glyptostrobus

and Thujites() foliage shoots Specimens of the bryophyte Ricciopsis

Fig 8 Line drawings of Box Canyon dicot leaf morphotypes (A) Ampelopsis acerifolia() (B) Cercidiphyllum sp (C) Chaetoptelea microphylla (D) X4 (Nyssa) (E) Lamanonia sp (F) X3(G) X8 (H) Magnolia ovata (I) Meliosma longifolia (J) X1 (K) X13 (L)X11 (M) X12 (N) X6(O) X7 (Corylites) (P) X14 (Q) X2 (Platycarya) (R) Zizyphoides 1047298abella (S) X5(T) X9All

scale bars 10 mm




Fig 9 Other paleo1047298oral remains from the Arkose Ridge Formation (A) Sparganium parvum blade with in1047298orescences (scale 10 by 5 mm) (B) photograph and (C) line drawing of Paleosecuridaca (scale 10 mm) (D) Cruciptera (scale 10 mm) (E) catkin (scale 10 mm) (F) incertis sedis 1 (scale 5 mm) (G) incertis sedis 2 (scale 5 mm) (H) incertis sedis 3 (scale5 mm) (I) Picea sp seed (scale 5 mm) (J) Metasequoia pollen cone (K) Ricciopsis sp (scale 5 mm) (L) Sabalites sp (scale 10 by 5 mm)




(Fig 9K)and Equisetites stems are alsoabundant In sandy lithofaciesas-sociations to the west at Gray Ridge (Figs 1 and 2) we recovered partialfrond impressions assignable to the coryphoid palm Sabalites (Fig 9L)

Leaf physiognomic approaches to estimating paleoclimatic parame-ters have been widely applied to Paleogene dicot leaf assemblages Leaf Margin Analysis (LMA) (Bailey and Sinnott 1916 Wolfe 1979 Wilf1997 Kowalski and Dilcher 2003) Leaf Area Analysis (LAA) (Wilf et al1998) and the Climate Leaf Analysis Multivariate Program (CLAMP)

(Spicer 2009 Yang et al 2011) were conducted on the Box Canyondicot leaf assemblageThe Leaf Margin Analysis (LMA) regression equations used here

are (1) LMA from Wolfe (1979) and Wing and Greenwood (1993)(Eqs (1)) and (2) PLMA from Kowalski and Dilcher (2003) (Eq (2))These equations were selected from among others (see Peppe et al2011 Su et al 2010) because of their widespread use among simi-larly analyzed Paleogene paleo1047298oras thereby allowing comparisonamong them Standard deviation was calculated using the number of morphotypes in the 1047298ora according to Eq (3) (from Wilf 1997) wherer is the number of morphotypes in the paleo1047298ora For PLMA the regres-sion slope of 363 replaces the LMA regression slope of 306 in Eq (3)

LMA LMAT C

frac14 306P thorn 114

eth1THORN

PLMA LMAT C


eth2THORN

σ LMAT frac12 frac14 306

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiP 1minusP eth THORN

r

r eth3THORN

CLAMP (Spicer 2009 Yang et al 2011) is a multivariate programthat estimates MAT as well as warm month mean temperature(WMMT) cold month mean temperature (CMMT) length of growingseason (LGS) growing season precipitation (GSP) meanmonthly grow-ing season precipitation (MMGSP) precipitation during the three con-secutive wettest months (3WET) precipitation during the three

consecutive driest months (3DRY) relative humidity (RH) speci1047297

c hu-midity (SH) and enthalpy (ENTHAL)Leaf Area Analysis (LAA Wilf et al 1998) considers the univariate

character of leaf size within a fossil dicot assemblage as a correlate of mean annual precipitation (MAP) The relationship among the moderncalibration dataset of 50 sites across West Africa as well as NorthCentral and South America is

ln MAP cmeth THORNfrac12 frac14 0548 M ln A mm2 h i

thorn 0768 eth4THORN

The morphotype diversity of the Box Canyon dicot leaf paleo1047298ora isnear the lower limit of the suggested assemblage diversity for theseanalyses (Burnham et al 2001 Peppe et al 2011 Yang et al 2011)In less diverse assemblages statistical con1047297dence in these methods

falls off sharply With seven of the 20 morphotypes exhibiting entiremargins (P = 035) LMAT by LMA is 1185 degC (plusmn322) and LMAT by

PLMA is 1493 degC (plusmn381) These results are in range of the CLAMPMAT results of 1136ndash1184 degC depending on which calibration datasetwas used (Table 2) LAA mean annual precipitation estimate resultsare 121 (+52minus37) cmyr

Fossil dicot leaves from the Box Canyon quarry were also assessedfor leaf damage using the guide of Labandeira et al (2007) Twelveunique damage types (DTs) were observed including examples of 1047297vedamage categories in order of abundance hole-feeding margin feed-

ing skeletonization galling and piercing and sucking (Fig 10) Seedpredation (DT73 or DT140 Labandeira et al 2007) was noted on onePaleosecuridaca sp specimen The quantitatively-collected Box Canyondicot leaf assemblage was analyzed for damage frequency according totwo published methods those of Currano et al (2008 2010) andthose of Smith (2008) The former protocol involves censusing damagetypeson all dicot leaves where more than half of thefoliar laminais pre-served The latter considers all dicot leaves or leaf fragments greaterthan 1 cm2 The damage frequency by these two methods is de1047297ned asthe percentage of the collection that exhibits some type of damageThis frequency is 127 (16126) for the half-leaf analysis while 92(22240) of leaves or leaf fragments greater than 1 cm2 were damaged(Table 3) Among the damaged Nhalf leaves 875 exhibited one dam-age type while the remainder exhibited two

Sunderlin et al (2011) conducted a similar ldquoN1 cm2 methodrdquo analy-sis on a larger collection from the partly coeval but more basinalsediments in the PaleocenendashEocene upper Chickaloon Formation insouth-central Alaska They found that 94 of leaves and leaf fragmentswere damaged (64 of 669) Like the Box Canyon assemblage hole-feeding was the dominant damage category with margin-feedingskeletonization and surface feeding also occurring The Chickaloondamage frequency by this method was low compared to the MiddleEocene Green River (34) and the Late Eocene Florissant (23) assem-blages of Smith (2008) The Box Canyon assemblage value (92) is alsolow by this method Although the half-leaf method was not performedon Chickaloon assemblages by Sunderlin et al (2011) Brannick et al(2012) report a preliminary damage frequency of 76 (76 of 1008) bythis method on a new large collection from the upper fossiliferousbeds of that unit (Early Eocene)Both this andthe Arkose Ridge damage

frequency (127) are low as well when compared to analyses on simi-lar age lower latitude paleo1047298oras in the Bighorn Basin (Currano et al2008 2010) (Table 3) However the high latitude Firkanten 1047298ora fromSpitsbergen has also been analyzed by the half-leaf method and yieldeda higher damage frequency (~22) under similar paleoclimatic condi-tions (Wappler and Denk 2011)

42 Paleofaunal elements

Three1047297sh fossilswere recovered from Box Canyon oneof which waspreserved well enough to be identi1047297ed to family It is a nearly completearticulated skeleton split into a part and counterpart (Fig 11) Becausemost of the bone was deteriorated and the rock matrix was resistantto acid the specimen was prepared by immersing it in 30 HCl to etch

out the remaining bone material This resulted in clearer bone impres-sions from which a black latex rubber peel could be made These peels

Table 2

CLAMP resultsfrom theBox Canyon fossil dicot collectionMAT = mean annual temperature WMMT = warm month mean temperature CMMT = coldmonthmean temperatureLGS = length of growing season GSP = growing season precipitation MMGSP = monthly mean growing season precipitation 3WET= precipitation during the 3 consecutivewettestmonths 3DRY = precipitation during the 3 consecutive driest months RH = relative humidity SH = speci1047297c humidity ENTHAL = enthalpy Run 1 used physiognomic calibration1047297leldquoPhysg3arcAZ rdquo along with its meteorological sites data ldquoMET3arcAZ rdquo Run 2 mdash ldquoPhysg3brcAZ rdquo and ldquoMET3brcAZ rdquo Run 3 mdash ldquoPhysg3arcAZ rdquo and ldquoGRIDMET3arcAZ rdquo Run 4 mdash ldquoPhysg3brcAZ rdquo andldquoGRIDMET3brcAZ rdquo See Yang et al (2011) for explanation of method

Run MAT(degC)

WMMT(degC)

CMMT(degC)

LGS(months)

GSP(cm)

MMGSP(cm)

3WET(cm)

3DRY (cm)

RH()

SH(gkg)

ENTHAL (kJkg)

1 1136 2079 284 675 6221 1017 3821 2197 709 749 30522 1167 2125 303 688 7024 1007 3979 1959 7004 718 30453 1157 2102 272 69 6978 101 5162 152 7508 75 31414 1184 2145 291 699 7315 1019 5183 1513 7363 729 3137




were then examined for details of bone morphology and other features(Fig 12) Although many details are poorly preserved the specimen ap-pears to belong in the smelt family Osmeridae (Appendix B)

Recent osmerids are mostly marine in some cases entering fresh-water to spawn and rarely restricted to freshwater They are foundtoday in both the Atlantic and Paci1047297c oceans and their tributaries butmostly in the northern regions Fossil osmerids are also known from

the Oligocene of Europe (eg Gaudant and Burkhardt 1984 Gaudant1985) Paleocene (Tiffanian) osmerids have also been reported fromthe freshwater deposits of the Paskapoo Formation of Alberta Canada(Wilson and Williams 1991)

A small collection of unionid bivalve fossils (Fig 13) was madefrom a dark gray very 1047297ne-grained sandstones at Gray Ridge (Figs 1and 2) Almost all specimens are preserved as internal molds with a

Fig 10Leaf damageon BoxCanyondicotleaf fossils(A) Hole feeding in Chaeotoptelea microphylla DT2(scale 5 mm)(B) piercing and sucking onX13DT47(scale 10mm)(C)gallingonX8 DT127 (scale 10 mm) (D) skeletonization on Zizyphoides 1047298abella DT16 (scale 5 mm) (E) margin feeding on X3 DT12 (scale 10 mm)Damage types according to Labandeira et al (2007)

Table 3

Leaf damage frequency by theN1 cm2 andhalf-leafanalyticalmethods mean annual temperature (MAT) estimates andmean annual precipitation (MAP) estimates forcomparable Pa-leocene and Eocene dicot assemblages

Paleo1047298ora (age)

(references)

N1 cm2 damage freq Half leaf damage freq MAT estimate

(degC)

MAP estimate

(cm)

Arkose Ridge (lPaleoceneeEocene)(This study)

92 127 114ndash149 121

Upper Chickaloon (eEocene)(Sunderlin et al 2011 Brannick et al 2012)

94 76 11ndash146 1546

Florissant (lEocene)(Smith 2008)

23 ndash 108ndash175 50

Green River (mEocene)(Smith 2008)

34 ndash 16ndash23 45ndash86

Bighorn Basin Wasatchian 2 (eEocene)(Currano et al 2008)

ndash 330 133ndash191

Bighorn Basin Wasatchian 0 (PE boundary)(Currano et al 2008)


Bighorn Basin Clarkforkian 3 (lPaleocene)(Currano et al 2008)


Firkanten Fm (~mPaleocene)(Wappler and Denk 2011)

ndash 219 97ndash144 1826




fewsamplesof externalmolds that do notpreserve theumboareaof theshell The specimens are tentatively assigned to Plesielliptio priscus(Good S pers comm 2012) (Appendix C)

5 Age of Arkose Ridge Formation at Box Canyon

This study includes new isotopic ages from the Arkose Ridge Forma-tion and overlying lavas and the methods and data are presented in the

supplementary materials online UPb zircon analyses were conductedfor one tuff and one sandstone using a laser-ablation-inductively-coupled-plasma-mass-spectrometer (LA-ICP-MS) at the ArizonaLaserChron Center utilizing methods described by Gehrels et al (20062008) Individual zircon crystals were separated from rock samplesusing standard mineral separation techniques and analyzed through in-dividual spot analyses Overall age determinations are based on 206Pb238U results alone because the relatively low U contents and young

Fig 11 A fossil smelt (family Osmeridae) from the upper Paleocene Arkose Ridge Formation of Alaska Part and counterpart of a single individual (UAMES 32075) measuring 52 mm intotal length (scale bars in mm)

Fig 12Latex peels from thespecimen in Fig11 (A)Rightside of head anterior facingright(B) Leftsideof head anteriorfacing left (C)caudal region shoeingdeeplyforkedtail(D) Closeup of caudal skeleton Abbreviations aa = anguloarticular br = branchiostegals cha = anterior ceratohyal d = dentary h = hyomandibula hy = hypural mx = maxilla op =opercle par = parasphenoid pcf = pectoral 1047297n pop = preopercle q = quadrate sm = supramaxilla sop = subopercle t = teeth u1 = ural centrum1 + preural centrum1

ud = urodermal or urodermals




ages of many analyzed crystals led to high uncertainties in theirmeasured 207Pb235U ages Results for individual crystals were used tocalculate a weighted mean 206Pb238U age for the youngest populationof crystals obtained from the tuff and sandstone samples Interpreta-tions focus on clusters of ages because single age determinations maybe compromised by Pb loss andor inheritance However it is highlyunlikely that three or more grains will experience Pb loss andor inher-itance but still yield thesame age (Dickinson and Gehrels 2009) Isoplot(Ludwig 2011) was used to calculate a TuffZirc age whichis themedianof the largest group of internally-concordant single-zircon ages that arestatistically coherent Additionally a 40Ar39Ar age was determined forlava that unconformably overlies the Arkose Ridge Formation The40Ar39Ar analysis was conducted at the Lehigh University geochronolo-gy laboratory on groundmass separated from this lava

Sandstonesample 072609CDK2 collected15 m above thebase of thesection (Fig 4) yields mid-Paleozoic through early Cenozoic 238U206Pbzircon ages The youngest ages (approximately 30 out of 95 analyses)fall between ca 55 and 60 Ma and a TuffZirc analysis of this popula-tion reveals a statistically coherent cluster of 23 grains that de1047297ne anage of 5884 + 072minus087Ma (Fig 14) Higher in the sectiontuff sam-ple 10AK20 collected 63 m below the fossil quarry ( Fig 4) yields aTuffZirc 238U206Pb age of 5837 + 192minus110 Ma based on spot analy-

ses of the 10 youngest grains (Fig 15) Lava sample 10AK17 collected133 m above the fossil quarry (Fig 4) yields an 40Ar39Ar plateau ageof 4823 plusmn 105 Ma (Fig 16) Together these new ages bracket the

sampled fossils to an interval between ~59 Ma and 48 Ma during LatePaleocenendashEarly Eocene time Age data from the stratigraphic intervalexposed between the fossil quarry and the lavas would further help tobracket the age of the quarry

6 Discussion

61 Depositional conditions and taphonomy

Through the measured section of the entire Arkose Ridge Formationat Box Canyon the 1047298uvial sub-environments of deposition shifted sig-

ni1047297cantly through time Gravelly braided river deposits indicating distalstream-dominated alluvial fan or fan-delta environments characterizethe lower measured strata The basin then evolved through a phase of dominantly stream1047298ow and 1047298ood-deposited sandstones that interca-lates with vegetated 1047298oodplain and ephemeral deposits from pondwater in the upper half of the measured section Plant growth habitats

Fig 13 Plesielliptio priscus bivalve from Gray Ridge Scale bar 10 mm

0

5

10

15

20

25

30

40 60 80 100 120 140 160 180 200 220

072609CDK2SandstoneBox Canyon

Ma

R el a t i v e pr o b a b i l i t y

N

u m b e r o f a n a l y s e s

0

2

4

6

8

50 Ma 55 Ma 60 Ma


N u m b e r o f a n a l y s e s

44

48

52

56

60

64

A g e

( M a )

Fig 14 Relative age-distribution plot of 206Pb238U ages for 95 detritalzircons from sand-stone sample072609CDK2collected 15m stratigraphically above thebase ofthe sedimen-tary successionat BoxCanyonNoteprincipleyoungest populationof agesbetween60 and55Ma Upper insetshows ages with 1 sigmaerrorsfor b61Ma grains lowerinset showsaTuffZirc age obtained by including analyses shown in black Analyses with anomalouslylarge errors (open boxes) or ages that differ signi1047297cantly from the main population(gray boxes) are not included in the age calculation See Fig 4 for stratigraphic position

of sample

0

1

2

3

4

5

6

45 55 65 75 85 95 105 115

Age (Ma)

45

55

65

75

85

95

105

N u m b e r o f A n a l y s e s

10AK20TuffBox Canyon

A g e ( M a )

Youngest Age Peak

580 MaTuffZirc Age 5837 +192-110 Ma(10 analyses)

Fig 15 Relative age-distribution plot of 206Pb238U ages for 29 zircons from tuff sample10AK20collected 63 m stratigraphically below the fossil quarry at Box CanyonNote prin-ciple youngest population of ages between 60 and 55 Ma Inset shows ages with 1 sigmaerrors for all analyses Ages shown as black boxes were used to calculate a TuffZirc ageof 5837 + 192minus110 (2 sigma) Analyses with anomalously large errors (open boxes)or ages that differ signi1047297cantly from the main population (gray boxes) are not included

in the age calculation See Fig 4 for stratigraphic position of sample

t = 4823 plusmn 105 Map

60

0 20 40 60 80 100

Cumulative 39Ar Released ()

A p p a r e n t A

g e ( M a )

40

45

50

55

10AK17 BasaltBox Canyon

Fig 16 40Ar39Ar age spectrum diagram for lava sample 10AK17 collected at the base of the lava succession at Box Canyon The 1047297nal seven heating steps de1047297ne a plateau age of 4823 plusmn 105 Ma (2σ ) Inverse isochron treatment of these steps yields an indistinguish-able isochron age of 4843 plusmn 114 Ma (2σ MSWD = 066) and an atmospheric trapped40

Ar36

Ar composition of 2881 plusmn 164 See Fig 4 for stratigraphic position of sample




became increasingly common up-section as this portion of the basinevolved toward 1047297ner-grained 1047298oodplainlacustrine facies associations

Stands of vegetation among the dynamic 1047298uvial regime were likelyto be only weakly stabilizing in the braidplains themselves low in thesection but persistent either in the adjacent uplandsterraces or inlong-stable portions of the distal regions of the depocenter Despite athick succession of strata well-preserved and diverse plant fossils arelimited to a rather small interval in the upper third of the exposed sec-

tion as the 1047298

oodplain evolved Plant fossil and sedimentological dataclearly show that 1047298oral compositions within distinct 1047298uvial facieswere dictated by tolerance thresholds of substrate stability The unsta-ble sedimentary environment provided temporary habitat onlyObserved changes in the vegetation community throughout the mea-sured sections is most likely attributable to 1047298oodplain evolution ratherthan to a 1047298oral succession forced by climate change

The Box Canyon paleo1047298oral assemblage from the study quarry isinterpreted to be parautochthonous with litter supplied either directlyinto a restricted lacustrine depocenter through litter fall or washedin from nearby during episodic 1047298ood conditions That the collectionis rich in leaf specimens with complete laminae and articulated leaf-lets on compound leaves (eg Chaetoptelea microphylla Fig 8C)suggests that the foliar material was not transported out of habitatover a great distance andthat it represents the diversity of the proximalforest stand (Burnham et al 1992) The rhythmically laminated and1047297ne-grained character of the lithofacies at the Box Canyon quarry alsoindicates deposition and preservation in a relatively tranquil sub-environment on the 1047298oodplain

The presence of aquatic fauna including 1047297sh (at Box Canyon) andunionid bivalves (at Gray Ridge) corroborates 1047298uvialndashlacustrine inter-pretations for the muddy lithofacies associations in the Arkose RidgeFormation The articulated1047297sh skeletons in rhythmically laminated silt-stones in the upper part of the section at Box Canyon indicate not onlythat ponded water was common in the 1047298oodplain during the laterstages of basin development but also that individually these bodies of water were long-standing features in the depositional environmentThe Gray Ridge bivalves elongate shell form with straight ventral shellmargin suggests a relatively swift water habitat in small 1047298uvial channels

(Eager 1948 Tevesz and Carter 1980) Preservation of bivalve speci-mens in random orientations indicates rapid burial during a 1047298ood 1047298ow

62 Paleoclimate and paleoecology

The presence of palm remains and leaf physiognomic analytical ap-proachesapplied here to the Arkose Ridge Box Canyon dicot assemblage

indicate warm and wet paleoclimatic conditions These results arebroadly parallel to the interpretation of warm temperate conditionsin the Paleogene Ketavik Formation to west (Parrish et al 2010)and to those from a similar suite of analyses of the distally-depositedChickaloon Formation (~ 11ndash146 degC MAT ~150 cmyr MAP Sunderlinet al 2011) in the same basin Despite being deposited in a more prox-imal upland environment the Arkose Ridge climatic conditions werecomparable to those within the basinalChickaloon depositional system

Previous work (Coley and Aide 1991 Wilf et al 2001 Wilf et al2005 Currano et al 2008 Wilf 2008 Adams et al 2010 ) shows thatwarmer and wetter conditions are correlated with increased frequencyof leaf damage in modern and ancient leaf assemblages However incomparing damage frequencies in the sub-polar paleolatitude ArkoseRidge and Chickaloon assemblages with those of the mid-latitude sites(Table 3) the low values in the Alaskan assemblages are unexpectedconsidering that leaf physiognomic estimates of MAT are only slightlycooler than the lower latitude assemblages and the Alaskan MAP esti-mates are higher These folivory analyses in the Arkose Ridge assem-blage therefore corroborate the suggestion by Sunderlin et al (2011)that a high latitude seasonal light regime and its effect on plant and in-sect herbivore life histories may be important in explaining the low ob-served damage rates The lack of a yearly-averaged warm high-latitudeforested ecosystemon Earth today may indicate that what we seein thePaleocenendashEocene record of Alaska is a non-analog paleoecological sys-tem in this respect However the reliability of leaf physiognomic esti-mates of ancient climate at such latitudes is problematic for the samereason that the calibration datasets become sparse at high latitudesand are in the Recent of such low diversity may lead to their limiteduse in comparison with the evidently warmer climatic conditions of the PaleocenendashEocene

63 Regional paleoenvironmental reconstruction

Lithofacies and paleo1047298oralpaleofaunal datasets in this and previousstudies (Flores and Stricker 1993 Trop et al 2003 Williams et al2010 Neff et al 2011 Sunderlin et al 2011) are combined to re1047297ne aregional paleoenvironmental and paleoecosystem reconstruction of

the Late PaleocenendashEarly Eocene Matanuska ValleyndashTalkeetna Moun-tains forearc basin (Fig 17) The Chickaloon and Arkose Ridge deposi-tional systems are broadly similar in their sedimentary provenanceand fossil remains yet representdifferent environmentswithina rapidlysubsiding and syndepositionally deforming basin Both units accumu-lated through Middle to Late Paleocene into Eocene time even thoughthe lateral contact between the units is as yet unrecognized in the

Fig 17LatePaleocenendashEarlyEocene depositional vegetative and paleoenvironmental modelin the Talkeetna MountainsndashMatanuska Valleybasin AbbreviationsCMF = CastleMountainFault A = fault displacement away T = fault displacement towards

Depositional framework modi1047297ed from Trop et al (2003) and Neff et al (2011)




1047297eld and possibly tectonically eroded by dextral strike-slip motion onthe Castle Mountain Fault The Arkose Ridge sedimentation is coarser-grained overall and deposited in upland 1047298uvial systems proximal tosouthern Talkeetna Mountains volcanic centers associated with slab-window subduction Chickaloon deposition is 1047297ner grained and moredistalin the basin represented by coal-rich 1047298uvial systems now exposedin the modern Matanuska Valley Evidence of regional volcanic activityin the form of volcaniclastics tuffs and lavas is far more extensive in

the Arkose Ridge measured successions than in basin-axis ChickaloondepositsAs discussed above analyses of the plant fossil record in these units

yield similar paleoclimate estimates and similar paleoecological resultsbut the nature of the paleobiological record in each formation re1047298ectsthe differing 1047298uvial environmentsFragmentary and coali1047297ed woody re-mains are typical in the braidplain gravels and sandy lithofacies in theArkose Ridge Formation Only when1047298uvial conditions become relative-ly quiet in the upper strata of that unit do thin mudrock lenses preservefoliar and reproductive plant remains in standing water deposits on the1047298anks of the gravelly braided rivers Chickaloon Formation mire and1047298oodplain depositional environments are more dominant in distal por-tions of the basin where large permineralized trees and forest litter re-mains are commonly preserved in coals and carbonaceous mudrocks(Neff et al 2011)

We propose a shallow-gradient uphill environmental transitionfrom a trunk river and associated tributary system to the paleo-southin the area represented by the Chickaloon Formation to an increas-ingly braided-alluvial landscape north in the area represented bythe Arkose Ridge Formation (Fig 17) Evidence of estuarine conditionsin Chickaloon sediments to the southwest in the Matanuska Valley(Trop et al 2003) and the similarity in leaf physiognomic estimates of paleoclimate from the Chickaloon and Arkose Ridge suggests low relief across the basin Conifer dominated mires together with stands of mixed hardwoodndashconifer forests 1047298ank meandering rivers in the basincenter (Chickaloon) while the latter are distributed less continuouslyacross stable regions among the braidplains of the Arkose Ridgedepocenter

7 Conclusions

Strata of the Late Paleocene Arkose Ridge Formation exposed atBox Canyon in south-central Alaska preserve a terrestrial depositionalenvironment with a diverse and well-preserved assemblage of fossildicot leaves and sparse but fully-articulated1047297sh body fossils Lithofaciesanalysis indicates that braided streams and lakes deposited conglom-erate sandstone siltstone shale and subordinate tuff and lignite inchannel overbank1047298oodplain lacustrine and lacustrine fan-delta sub-environments Up-section lithofacies transitions re1047298ect enhanced1047298ood-plainndashlacustrine deposition togetherwith enhanced volcanic depositionand erosion of volcanic detritus from the nearbyCaribou Creek volcanic1047297eld Incipient paleosols sparse lignite and sporadic plant fossil occur-rences suggest temporary habitats in an aggrading wet environment

characterized by perennial stream 1047298ow standing water and localizedmire development Paleocurrent indicators detrital zircon ages andconglomerate compositional data indicate southward sediment trans-port from JurassicndashPaleocene remnant arc plutons and coeval LatePaleocenendashEarly Eocene volcanic centers

Macro1047298ora taphonomic data suggest frequent delivery of leaf litterto stagnant ponded water minimal out-of-habitat transport and rapidburial following deposition Leaf physiognomic analysis on the assem-blage of broadleaf macrofossils indicates warm to cool temperate cli-mate conditions Entire (smooth) margins are characteristic of sevenof the twenty discrete dicot morphospecies (P = 035) Estimates of mean annual temperature (using LMA PLMA and CLAMP methods)from Late Paleocenendashearliest Eocene leaf fossil assemblages in theArkose Ridge Formation at Box Canyon indicate warm-temperate con-

ditions (114deg to 149 degC plusmn ~3 degC) Leaf size analysis indicates moderate

to wet climatic conditions of ~120 cmyr consistent with interpreta-tions of the lithofacies data

Isotopic ages from tuff interbeds together with the youngest ageclusters in sandstones constrain the timing of sediment accumulationat Box Canyon to ca 59ndash55 Ma (Late Paleocene) Sedimentary stratawere subsequently deformed and overlain by basaltic lavas by ca48 Ma judging from new 40Ar39Ar ages from the lowermost lavas atBox Canyon that overlie the sedimentary strata along a prominent an-

gular unconformityIntegration of this studys results with similar recent data fromcoeval strata exposed in other parts of Alaska including the nearbyMatanuska Valley and the Alaska Peninsula allows for an importantnew window into high-latitude terrestrial forested ecosystems duringa global hothouse climate phase and thus holds implications in under-standing how ecological systems respond to non-analog warm high-latitude environmental conditions

Acknowledgments

This project was supported by National Science Foundation grantsEAR0910545 to J Trop and EAR0910821 to B Idleman and a RichardK Mellon Fellowship to D Sunderlin We thank S Good for examiningbivalve fossils E Bauer C Kassab C Kortyna K Ridgway and T Szwarcfor contributions in the 1047297eld A LeComte for laboratory analysis andcollections management D Bradley and his family for their hospitalityand Dave and Debbie King for their hospitality and logistical supportC Kassab drafted earlier versions of several 1047297gures G Gehrels andM Pecha helped us acquire geochronologic data and National ScienceFoundation grant EAR-0443387 supported the University of ArizonaLaserChron Center This study bene1047297ted from discussions with D Brad-ley R Cole D LePain R Stanley A Till P Wilf andCJ Williams and re-views from F Surlyk and two anonymous reviewers

Appendix A Leaf morphotypes in the Arkose Ridge Formation at

Box Canyon

All scale bars = 1 cm times 05 cmldquo Ampelopsisrdquo acerifolia Wang

Simple mesophyll-size elliptic leaf with medial symmetrical laminaand marginal petiolate attachment Margins are crenate and unlobedwith rounded base andapex andan obtuse leaf apex angle The primaryvein framework is actinodromous with 1047297ve basal veins Veins terminate

at apex of teeth




Cercidiphyllum sp Siebold amp Zucc

Simple symmetrical leaves with marginal petiolate attachment

ovate shape and microphyll-size Leaf margins are crenate and unlobedwith an convex apex and cordate base shape Tooth spacing is irregularwith one major order of teeth Vein framework is actinodromous typi-cally with four basal veins

Chaetoptelea microphylla Newberry

Pinnately compound petiolate leaves with opposite lea1047298et organiza-tion and petiolulate lea1047298et attachment Lea1047298ets elliptic symmetricalnanophylls each unlobed and with serrate margins The lea1047298et apicesare acute and the base is convex Primary venation is in a pinnate frame-work and secondary veins terminate at tooth apices

Lamanonia sp Vell

Simple elliptic nanophylls with base asymmetrical bases and acutestraight apices One order of serrate margin teeth are regularly spacedat 4 teethcm The primary vein framework is pinnate

Magnolia ovata A St-Hil

Simple petiolate leaf of mesophyll size Elliptic leaves are unlobed

with a convex base and untoothed margin Veins framework is pinnatewith central vein notably wide




Meliosma longifolia Heer

Simple pinnate leaf of notophyll size exhibiting dentate margins at3 teethcm Tooth spacing is regular and the leaf apex is acuminateTeeth sinuses are angular and vein termination occurs at the apex of the teeth

X1

Simple petiolate nanophyll with an ovate symmetrical shape entiremargin and rounded base Vein framework is basal actinodromous with

6 basal veins

X2 (Platycarya sp Siebold amp Zucc)

Simple petiolate elliptic notophyll with acute straightapex and acutedecurrent base Leaf is unlobed with serrate margins and primary veinframework is pinnate Similar to X5 and X8 Leaf attachment and basalsecondary venation delineates this morphotype from X5 Curved sec-ondary veins differ from those in X8

X3

Simple elliptic mesophyll with unlobed crenate margins convex leaf

bases and an acute apex angle Tooth spacing is irregular with ~2 teethcm Primary vein framework is pinnate with veins terminating on thedistal 1047298ank of the teeth




X4 (Nyssa sp Linneaus)

Simple petiolate elliptic notophyll with unlobed untoothed marginLeaf apex is acute and base is decurrent Vein framework is pinnate

X5 (Juglandaceae)

Once pinnately compound leaves with sessile lea1047298et attachmentLea1047298et laminae arenotophyll in size and obovate Basal insertion is asym-metrical and unlobed margins are serrate Irregularly serrate marginswith one order of teeth at ~ 5 teethcm Lea1047298et venation framework ispinnate with veins terminating on the distal 1047298ank of the teeth Similarto X2 and X8 Basal attachment and venation delineates this morphotype

from X2 Curved secondary veins differ from those in X8

X6

Simple petiolate ovate microphyll with asymmetrical cordatebase and straight acute apex Petiole exhibits a sheathing base Unlobedleaf margins are untoothed and the primary vein framework is basalactinodromous

X7 (Corylites sp Gardner)

Simple petiolate ovate notophyll with cordate base and straightacute apex Unlobed leaf margins are irregularly serrate with three or-ders of teeth spaced at ~4 teethcm Pinnate vein framework and veinsterminate on distal 1047298ank of the teeth Symmetry in base and secondary

vein anglesspacing delineate this morphotype from X13




X8

Simple unlobed elliptic notophyll Tooth spacing is regular for oneorder of teeth at ~4 teethcm Primary vein framework is pinnate Ser-rate margins and secondary vein shape delineate this morphotype

from X2 and X5

X9

Simple petiolate elliptic mesophyll with untoothed margin and con-cave base shapePrimary vein framework is pinnate with one basal veinat insertion

X11

Simple petiolate ovate microphyll with acute straight apex and ob-tuse rounded base Margins are unlobed crenate with irregularly spacedtwo orders of teeth at ~3 teethcm Primary vein framework is pinnate

X12

Simple petiolate elliptic microphyll with acute apex and acute con-vex base Base insertion is asymmetrical Margins are entire and the pri-mary vein framework is pinnate

X13

Simple petiolate ovate notophyll with basal extension asymmetryAcute straight apex and obtuse rounded base Irregularly serrate withtwo orders of teeth at ~4 teethcm Primary vein framework is pinnateAsymmetry in base and secondary vein anglesspacing delineate this

morphotype from X7








implications In Meyer HW Smith DM (Eds) Paleontology of the Upper EoceneFlorissant Formation Colorado Geological Society of America Special Paper 435pp 89ndash103

SmithRY Basinger JFGreenwoodDR 2011EarlyEocene plantdiversityand dynamicsin the Falkland 1047298ora Okanagan Highlands British Columbia Canada PalaeobiodiversPalaeoenviron 92 309ndash328

Spicer RA 2009 CLAMP Online Climate Leaf Analysis Multivariate Program Joint Pro- ject Between the Open University UK and the Institute of Botany Chinese Academyof Science Beijing updated 12282010 httpclampibcasaccn

Stamatakos JA Kodama KP Pavlis TL 1988 Paleomagnetism of Eocene plutonicrocks Matanuska Valley Alaska Geology 16 618ndash622

Stamatakos JA Kodama KP Vitorrio LF Pavlis TL 1989 Paleomagnetism of Creta-ceous and Paleocene sedimentary rocks across the Castle Mountain Fault south-central Alaska InHillhouse JW (Ed) DeepStructure andPast Kinematics of Accret-ed Terranes American Geophysical Union Geophysical Monograph Series v 50pp 151ndash177

Steiger RH Jager E 1977 Subcommission on geochronology Convention on the use of decay constants in geo- and cosmochronology Earth Planet Sci Lett 36 (3)359ndash362

Su T Xing Y-W LiuY-SJaques FMB Chen W-Y Huang Y-J Zhou Z-K 2010 Leaf margin analysis A new equation from humid to mesic forests in China PALAIOS 25(4) 234ndash238

Sunderlin D Loope G Parker NE Williams CJ 2011 Paleoclimatic and paleoecologi-cal implications of a PaleocenendashEocene fossil leaf assemblage Chickaloon FormationAlaska Palaios 26 335ndash345

Szwarc T Trop JM Idleman B 2011 New stratigraphic and detrital geochronologicconstraints on deformation deposition and dextral displacement along the CastleMountain fault south-central Alaska Geol Soc Am Abstr Programs 43 439

Tevesz MJS Carter JUG 1980 Environmental relationships of shell form and structureofUnionaceanbivalves InRhoad DCLutzRA (Eds)SkeletalGrowth ofAquatic Or-

ganisms Biological Records of EnvironmentalChangePlenumPress NY pp295ndash322Tripati A Elder1047297eld H 2005 Deep-sea temperature and circulation changes at the

PaleocenendashEocene Thermal Maximum Science 308 1894ndash1898Trop JM Ridgway KD 2007 Mesozoic and Cenozoic tectonic growth of southern

Alaska a sedimentary basin perspective In Ridgway KD Trop JM Glen JMG(Eds) Tectonic Growth of a Collisional Continental Margin Crustal Evolution of Southern Alaska Geological Society of America Special Paper 431 pp 55ndash94

Trop JM Ridgway KD Spell TL 2003 Sedimentary record of transpressional tectonicsand ridge subduction in the Tertiary Matanuska ValleyndashTalkeetna Mountains forearcbasin southern Alaska In Sisson VB Roeske S Pavlis TL (Eds) Geology of aTranspressional Orogen Developed During Ridgendashtrench Interaction Along theNorth Paci1047297c Margin Geological Society of America Special Paper 371 pp 89ndash118

Walker BJ 2009 Gastropod assemblages from the Tertiary Chickaloon Formation insouthern Alaska In deWet AP Mertzman S Erb K Kadyk D (Eds) Proceedingsof the Twenty-second Annual Keck Research Symposium in Geology (Franklin ampMarshall College April 2009) The Consortium Colleges and the National ScienceFoundation pp 101ndash105

Wappler T Denk T 2011 Herbivory in early Tertiary Arctic forests PalaeogeogrPalaeoclimatol Palaeoecol 310 283ndash295

Weijers JWH Schouten S Sluijs A Brinkhuis H Sinninghe Damste JS 2007 Warmarctic continents during the PalaeocenendashEocene thermal maximum Earth PlanetSci Lett 261 230ndash238

Wilf P 1997 When are leaves good thermometers A new case for leaf margin analysisPaleobiology 23 373ndash390

Wilf P 2000 Late Paleocenendashearly Eocene climate changes in southwestern Wyomingpaleobotanical analysis Geol Soc Am Bull 112 292ndash307

Wilf P 2008 Insect-damaged fossil leaves record food web response to ancient climatechange and extinction New Phytol 178 486ndash502

Wilf P Labandeira CC 1999 Response of plantndashinsect associations to Paleocenendash

Eocene warming Science 284 2153ndash2156Wilf P Wing SL Greenwood DR Greenwood CL 1998 Using fossil leaves as

paleoprecipitation indicators an Eocene example Geology 26 203 ndash206Wilf P Labandeira CC Johnson KR Coley PD Cutter AD 2001 Insect herbivory

plant defense and early Cenozoic climate change Proc Natl Acad Sci U S A 986221ndash6226Wilf P LabandeiraJohnson KR Cuneo NR 2005 Richness of plantndashinsect associations

in Eocene Patagoniaa legacy for South American biodiversity Proc Natl Acad Sci US A 102 8944ndash8948

Williams CJ Trostle K Sunderlin D 2010 Fossil wood in coal-forming environmentsof the late Paleocenendashearly Eocene Chickaloon Formation Palaeogeogr PalaeoclimatolPalaeoecol 295 363ndash375

Wilson MVH Williams RRG 1991 New Paleocene genus and species of smelt(Teleostei Osmeridae) from freshwater deposits of the Paskapoo Formation AlbertaCanada and comments on osmerid phylogeny J Vertebr Paleontol 11 434ndash451

Wing SL 1998 Late PaleogenendashEarly Eocene 1047298oral and climatic change in the BighornBasin Wyoming In Aubry M Lucas S Berggren W (Eds) Late PaleocenendashEarlyEocene Climatic and Biotic Events in the Marine and Terrestrial Records ColumbiaUniversity Press New York pp 380ndash400

Wing SL Greenwood DR 1993 Fossils and fossil climate the case for equable conti-nental interiors in the Eocene Philos Trans R Soc Lond 341B 243ndash252

Wing SL Harrington GJ Smith FA Bloch JI Boyer DM Freeman KH 2005 Tran-sient1047298oralchange and rapid global warming at the PaleocenendashEocene boundary Sci-

ence 310 993ndash996Winkler GR 1992 GeologicMap and SummaryGeochronology of the 1deg times 3deg Anchorage

Quadrangle Southern Alaska Miscellaneous Investigations Series M-I-2283 USGeol Surv 1250000

Wolfe JA 1966 Tertiary plants from the Cook Inlet region U S Geol Surv Prof Pap398-B 1ndash32

Wolfe JA 1977 Paleogene 1047298oras from the Gulf of Alaska region U S Geol Surv ProfPap 997 1ndash108

Wolfe JA 1979 Temperature parameters of humid to mesic forests of eastern Asia andrelation to forests of other regions of the northern hemisphere and Australia U SGeol Surv Prof Pap 1106 1ndash71

Wolfe JA Hopkins DM Leopold EB 1966 Tertiary stratigraphy and paleobotany of the Cook Inlet region Alaska U S Geol Surv Prof Pap 398-A 1ndash29

Yang J Spicer RA Spicer TEV Li C-S 2011 lsquoCLAMP Onlinersquo a new web-basedpalaeoclimate tool and its application to the terrestrial Paleogene and Neogene of North America Palaeobiodivers Palaeoenviron 91 163ndash183

Zachos JC Pagani M Sloan L Thomas E Billups K 2001 Trends rhythms and aber-rations in global climate 65 Ma to present Science 292 686ndash693

Zachos JC Dickens GR Zeebe RE 2008 An early Cenozoic perspective on greenhousegas warming and carbon cycle dynamics Nature 451 279ndash283




0 20 km

N

ArkoseRidge

LavaMtn

GrayRidge

BoxCanyon

Caribou Creek volcanic field

WillowCreek

Govrsquot Peak

Al a s k a

Fig1

Sou thern

Talkee tn

a Moun tains

Tv

Tar

Tar

Tar

Tar

Chugach subduction complex

TcTw

TcTwMa tanu

ska Valle

y

TcTw

TcTw

Tar

Fig 1 Geologic map showing Arkose Ridge Formation measured stratigraphic section locations and paleocurrent data This study focuses on Paleocene sedimentary and volcanic strataexposed north (orange-Tar) of the Castle Mountain fault at Box Canyon and to a lesser extent at Lava Mountainand Gray Ridge Abbreviations Tar mdash PaleoceneArkose Ridge FormationTcTw mdash PaleocenendashEocene Chickaloon and Wishbone Formations Tv mdash Eocene Caribou Creek volcanicRose diagrams represent structurally restored paleocurrent azimuths from Clardy (1974) Little (1988) Trop et al (2003) Cole et al (2006) and Donaghy (2012)

0 m

1 7 8 3

Arkose Ridge


0 m

5 0 0

9 3 1

Jurassic granitoid

9 6 5

Gray Ridge Lava Mtn North

1770

1360

1140

844

676

378

615

257

875

1 0 m

5 0 0

1 0 0 0

1 5 0 0

5 0 0

Jurassic granitoid

5 0 0

0 m

Jurassic volcanics

Box Canyon

9 9 3

15

770

619

Conglomerate

Sandstone

MudstoneShale

Covered Interval

Lava

T u f f

Explanation


Willow Creek

0 m

1 5 0

3 0 0

4 6 7

265

170

West East

Q

n = 208 n = 421 n = 780 n = 1140N = 2 N = 4 N = 7 N = 11

n=707

N=7

Lava sample for ArAr age

Tuff sample for UPb age

SS sample for UPb zircon age

1

2

2

1

Bivalve fossil

Palm fossils

FossilQuarry

volcanic plutonic

meta-morphic

other

conglomerate clast types

Fig 2 Generalizedlogs (inmeters) of measured stratigraphic sectionsof Paleocene sedimentary andvolcanic strataexposedin thesouthern Talkeetna Mountains (seeFig1)Tuffages areUPb zircon analyses whereas lava ages are 40Ar39Ar analyses on groundmass n = total number of clasts counted N = number of conglomerate beds sampledIsotopic ages from tuff and lava are from Idleman et al (2011) Squares mark position of sandstone samples for detrital geochronologic ages reported by Kortyna et al (2013) that yield

maximum depositional ages consistent with the tuff and lava ages Pie diagrams above sections show summary of conglomerate clast compositions reported by Kortyna et al (2013)



























Explanation

g c b

0m

25

50

75

100

125

150

175

200

225

250

275

300

400

325

350

375

500

425

450

475

525

550

GcmSm

Gcmi

Gcm

Gcm

Gcmi

Gcmi

Gcm

Gcm

Gcm

Gmm

GmmSm

GmmSm

ShSr

GcmGcmi

GcmSmFsc

GcmGcm

GcmGmmSmSh

SmStShSm

StSmSh

SmSh

SmSh

SmSrFsm

GcmSm

SmSr

StSm

Gcmi

Gcm

Gmm

Gmm

Fsm

SmSh

SmStGcmGmm

FscSmGcmiGcm

Gmm

SmSh

SmStSpFscFsm

SmSt

SmSrSt

FmmFsc

FscStSr

SrSlSt

Fsc

St

SmStSh

pf m vc

575

600

625

650

675

700

FscFmm

StSm

GcmGcmSt

StSmSpGcm

ShSmFsmFsl

Sm

StFsm

St

Gcm

725

750

775

800

Tuff

993

StFsmFsl

StSm

Tuff

TuffSt

Sm St Fsm

Lavas

Sm St


Lavas

Lavas

525

550

FmmFsc

FscStSr

SrShSt

Fsc

St

SmStSh

500

g c bpf m vc

Q

ArAr lava sample

UPb tuff sample

UPb ss sample


Fossil leaves

Fossil branches

GA

GA

VA

MA

MA

MA

SA

2

1

Q


GA

top eroded


s - siltstonetuff

f - fine sandtuff


g - granulelapilli

c - cobblelapilli

b - boulderblock

s g cf cs b






Covered Interval

Carbonaceous debris

Fish fossils



Granule-pebble lags

Columar joints


072609CDK2

10AK20

2 10AK17

10AK17

210AK20

072609CDK2










A B

C D

E F

JTrt

JTrt

Gcm

Gcm

St

Sh

Sm

GA

MA

Q

Fsm

St


right)






et al 2010)






G H

I J

K L

VA

MA

Bentonite

Fsc

Fsc

MA

GA

Fig 5 (continued)








311 Description




312 Interpretation


Table 1







































321 Description



322 Interpretation






331 Description



335

340

345

350

355

360

365

370

375

380

SmStSpSh

Sh

SmStSh

ShSm

Sm

ShSm

StSmShSm

SmSh

FslFscSh

Sh

SmSh

Fsc

Smv

SmFsc

SmShSmv

s g cbf c

50

55

60

65

70

75

80

85

90

95

100

Gcmi

Gcmi

(174 cm)

Gcm

Gcm

(124 cm)

Gcmi

(135 cm)

s g cbf c

500

505

510

515

520

525

530

535

540

545

550

s g cbf c

SmSrSt

FmmFsc

Sm

StSr

Fsc

Fsc

FscCoal

St

Fsc

Gcm

Gcm

Gcm

Gcm

GcmSm

Sm

Gcm

Gcm

Sm

Covered

Fsc

FscCoal

St

A B C

St

Fsc

Fsc

tuffaceous

SrSt







332 Interpretation



341 Description



342 Interpretation









Arbitrary Base

10 cm

20 cm

30 cm

40 cm

50 cm

60 cm

70 cm

coarsesandstone

1-5 cm coalified

wood fragments


fossil seeds

leaves

purplebrown mottled

claystone

heavily weathered


siltstone varves

microbial horizons


soil at quarry top

Clay Silt Sand



















scale bars 10 mm












LMA LMAT C


eth1THORN

PLMA LMAT C


eth2THORN



r

r eth3THORN

















Table 2


Run MAT(degC)

WMMT(degC)

CMMT(degC)

LGS(months)

GSP(cm)

MMGSP(cm)

3WET(cm)

3DRY (cm)

RH()

SH(gkg)

ENTHAL (kJkg)

1 1136 2079 284 675 6221 1017 3821 2197 709 749 30522 1167 2125 303 688 7024 1007 3979 1959 7004 718 30453 1157 2102 272 69 6978 101 5162 152 7508 75 31414 1184 2145 291 699 7315 1019 5183 1513 7363 729 3137









Table 3



(references)


(degC)

MAP estimate

(cm)


92 127 114ndash149 121


94 76 11ndash146 1546






























6 Discussion





0

5

10

15

20

25

30

40 60 80 100 120 140 160 180 200 220


Ma


N


0

2

4

6

8

50 Ma 55 Ma 60 Ma



44

48

52

56

60

64

A g e

( M a )


of sample

0

1

2

3

4

5

6

45 55 65 75 85 95 105 115

Age (Ma)

45

55

65

75

85

95

105



A g e ( M a )

Youngest Age Peak





60

0 20 40 60 80 100


A p p a r e n t A

g e ( M a )

40

45

50

55



Ar36







tion as the 1047298





















7 Conclusions








Acknowledgments



Box Canyon



at apex of teeth









Lamanonia sp Vell










X1


6 basal veins



X3








X5 (Juglandaceae)



X6








X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7









































































Explanation

g c b

0m

25

50

75

100

125

150

175

200

225

250

275

300

400

325

350

375

500

425

450

475

525

550

GcmSm

Gcmi

Gcm

Gcm

Gcmi

Gcmi

Gcm

Gcm

Gcm

Gmm

GmmSm

GmmSm

ShSr

GcmGcmi

GcmSmFsc

GcmGcm

GcmGmmSmSh

SmStShSm

StSmSh

SmSh

SmSh

SmSrFsm

GcmSm

SmSr

StSm

Gcmi

Gcm

Gmm

Gmm

Fsm

SmSh

SmStGcmGmm

FscSmGcmiGcm

Gmm

SmSh

SmStSpFscFsm

SmSt

SmSrSt

FmmFsc

FscStSr

SrSlSt

Fsc

St

SmStSh

pf m vc

575

600

625

650

675

700

FscFmm

StSm

GcmGcmSt

StSmSpGcm

ShSmFsmFsl

Sm

StFsm

St

Gcm

725

750

775

800

Tuff

993

StFsmFsl

StSm

Tuff

TuffSt

Sm St Fsm

Lavas

Sm St


Lavas

Lavas

525

550

FmmFsc

FscStSr

SrShSt

Fsc

St

SmStSh

500

g c bpf m vc

Q

ArAr lava sample

UPb tuff sample

UPb ss sample


Fossil leaves

Fossil branches

GA

GA

VA

MA

MA

MA

SA

2

1

Q


GA

top eroded


s - siltstonetuff

f - fine sandtuff


g - granulelapilli

c - cobblelapilli

b - boulderblock

s g cf cs b






Covered Interval

Carbonaceous debris

Fish fossils



Granule-pebble lags

Columar joints


072609CDK2

10AK20

2 10AK17

10AK17

210AK20

072609CDK2










A B

C D

E F

JTrt

JTrt

Gcm

Gcm

St

Sh

Sm

GA

MA

Q

Fsm

St


right)






et al 2010)






G H

I J

K L

VA

MA

Bentonite

Fsc

Fsc

MA

GA

Fig 5 (continued)








311 Description




312 Interpretation


Table 1







































321 Description



322 Interpretation






331 Description



335

340

345

350

355

360

365

370

375

380

SmStSpSh

Sh

SmStSh

ShSm

Sm

ShSm

StSmShSm

SmSh

FslFscSh

Sh

SmSh

Fsc

Smv

SmFsc

SmShSmv

s g cbf c

50

55

60

65

70

75

80

85

90

95

100

Gcmi

Gcmi

(174 cm)

Gcm

Gcm

(124 cm)

Gcmi

(135 cm)

s g cbf c

500

505

510

515

520

525

530

535

540

545

550

s g cbf c

SmSrSt

FmmFsc

Sm

StSr

Fsc

Fsc

FscCoal

St

Fsc

Gcm

Gcm

Gcm

Gcm

GcmSm

Sm

Gcm

Gcm

Sm

Covered

Fsc

FscCoal

St

A B C

St

Fsc

Fsc

tuffaceous

SrSt







332 Interpretation



341 Description



342 Interpretation









Arbitrary Base

10 cm

20 cm

30 cm

40 cm

50 cm

60 cm

70 cm

coarsesandstone

1-5 cm coalified

wood fragments


fossil seeds

leaves

purplebrown mottled

claystone

heavily weathered


siltstone varves

microbial horizons


soil at quarry top

Clay Silt Sand



















scale bars 10 mm












LMA LMAT C


eth1THORN

PLMA LMAT C


eth2THORN



r

r eth3THORN

















Table 2


Run MAT(degC)

WMMT(degC)

CMMT(degC)

LGS(months)

GSP(cm)

MMGSP(cm)

3WET(cm)

3DRY (cm)

RH()

SH(gkg)

ENTHAL (kJkg)

1 1136 2079 284 675 6221 1017 3821 2197 709 749 30522 1167 2125 303 688 7024 1007 3979 1959 7004 718 30453 1157 2102 272 69 6978 101 5162 152 7508 75 31414 1184 2145 291 699 7315 1019 5183 1513 7363 729 3137









Table 3



(references)


(degC)

MAP estimate

(cm)


92 127 114ndash149 121


94 76 11ndash146 1546






























6 Discussion





0

5

10

15

20

25

30

40 60 80 100 120 140 160 180 200 220


Ma


N


0

2

4

6

8

50 Ma 55 Ma 60 Ma



44

48

52

56

60

64

A g e

( M a )


of sample

0

1

2

3

4

5

6

45 55 65 75 85 95 105 115

Age (Ma)

45

55

65

75

85

95

105



A g e ( M a )

Youngest Age Peak





60

0 20 40 60 80 100


A p p a r e n t A

g e ( M a )

40

45

50

55



Ar36







tion as the 1047298





















7 Conclusions








Acknowledgments



Box Canyon



at apex of teeth









Lamanonia sp Vell










X1


6 basal veins



X3








X5 (Juglandaceae)



X6








X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7























































A B

C D

E F

JTrt

JTrt

Gcm

Gcm

St

Sh

Sm

GA

MA

Q

Fsm

St


right)






et al 2010)






G H

I J

K L

VA

MA

Bentonite

Fsc

Fsc

MA

GA

Fig 5 (continued)








311 Description




312 Interpretation


Table 1







































321 Description



322 Interpretation






331 Description



335

340

345

350

355

360

365

370

375

380

SmStSpSh

Sh

SmStSh

ShSm

Sm

ShSm

StSmShSm

SmSh

FslFscSh

Sh

SmSh

Fsc

Smv

SmFsc

SmShSmv

s g cbf c

50

55

60

65

70

75

80

85

90

95

100

Gcmi

Gcmi

(174 cm)

Gcm

Gcm

(124 cm)

Gcmi

(135 cm)

s g cbf c

500

505

510

515

520

525

530

535

540

545

550

s g cbf c

SmSrSt

FmmFsc

Sm

StSr

Fsc

Fsc

FscCoal

St

Fsc

Gcm

Gcm

Gcm

Gcm

GcmSm

Sm

Gcm

Gcm

Sm

Covered

Fsc

FscCoal

St

A B C

St

Fsc

Fsc

tuffaceous

SrSt







332 Interpretation



341 Description



342 Interpretation









Arbitrary Base

10 cm

20 cm

30 cm

40 cm

50 cm

60 cm

70 cm

coarsesandstone

1-5 cm coalified

wood fragments


fossil seeds

leaves

purplebrown mottled

claystone

heavily weathered


siltstone varves

microbial horizons


soil at quarry top

Clay Silt Sand



















scale bars 10 mm












LMA LMAT C


eth1THORN

PLMA LMAT C


eth2THORN



r

r eth3THORN

















Table 2


Run MAT(degC)

WMMT(degC)

CMMT(degC)

LGS(months)

GSP(cm)

MMGSP(cm)

3WET(cm)

3DRY (cm)

RH()

SH(gkg)

ENTHAL (kJkg)

1 1136 2079 284 675 6221 1017 3821 2197 709 749 30522 1167 2125 303 688 7024 1007 3979 1959 7004 718 30453 1157 2102 272 69 6978 101 5162 152 7508 75 31414 1184 2145 291 699 7315 1019 5183 1513 7363 729 3137









Table 3



(references)


(degC)

MAP estimate

(cm)


92 127 114ndash149 121


94 76 11ndash146 1546






























6 Discussion





0

5

10

15

20

25

30

40 60 80 100 120 140 160 180 200 220


Ma


N


0

2

4

6

8

50 Ma 55 Ma 60 Ma



44

48

52

56

60

64

A g e

( M a )


of sample

0

1

2

3

4

5

6

45 55 65 75 85 95 105 115

Age (Ma)

45

55

65

75

85

95

105



A g e ( M a )

Youngest Age Peak





60

0 20 40 60 80 100


A p p a r e n t A

g e ( M a )

40

45

50

55



Ar36







tion as the 1047298





















7 Conclusions








Acknowledgments



Box Canyon



at apex of teeth









Lamanonia sp Vell










X1


6 basal veins



X3








X5 (Juglandaceae)



X6








X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7




















































et al 2010)






G H

I J

K L

VA

MA

Bentonite

Fsc

Fsc

MA

GA

Fig 5 (continued)








311 Description




312 Interpretation


Table 1







































321 Description



322 Interpretation






331 Description



335

340

345

350

355

360

365

370

375

380

SmStSpSh

Sh

SmStSh

ShSm

Sm

ShSm

StSmShSm

SmSh

FslFscSh

Sh

SmSh

Fsc

Smv

SmFsc

SmShSmv

s g cbf c

50

55

60

65

70

75

80

85

90

95

100

Gcmi

Gcmi

(174 cm)

Gcm

Gcm

(124 cm)

Gcmi

(135 cm)

s g cbf c

500

505

510

515

520

525

530

535

540

545

550

s g cbf c

SmSrSt

FmmFsc

Sm

StSr

Fsc

Fsc

FscCoal

St

Fsc

Gcm

Gcm

Gcm

Gcm

GcmSm

Sm

Gcm

Gcm

Sm

Covered

Fsc

FscCoal

St

A B C

St

Fsc

Fsc

tuffaceous

SrSt







332 Interpretation



341 Description



342 Interpretation









Arbitrary Base

10 cm

20 cm

30 cm

40 cm

50 cm

60 cm

70 cm

coarsesandstone

1-5 cm coalified

wood fragments


fossil seeds

leaves

purplebrown mottled

claystone

heavily weathered


siltstone varves

microbial horizons


soil at quarry top

Clay Silt Sand



















scale bars 10 mm












LMA LMAT C


eth1THORN

PLMA LMAT C


eth2THORN



r

r eth3THORN

















Table 2


Run MAT(degC)

WMMT(degC)

CMMT(degC)

LGS(months)

GSP(cm)

MMGSP(cm)

3WET(cm)

3DRY (cm)

RH()

SH(gkg)

ENTHAL (kJkg)

1 1136 2079 284 675 6221 1017 3821 2197 709 749 30522 1167 2125 303 688 7024 1007 3979 1959 7004 718 30453 1157 2102 272 69 6978 101 5162 152 7508 75 31414 1184 2145 291 699 7315 1019 5183 1513 7363 729 3137









Table 3



(references)


(degC)

MAP estimate

(cm)


92 127 114ndash149 121


94 76 11ndash146 1546






























6 Discussion





0

5

10

15

20

25

30

40 60 80 100 120 140 160 180 200 220


Ma


N


0

2

4

6

8

50 Ma 55 Ma 60 Ma



44

48

52

56

60

64

A g e

( M a )


of sample

0

1

2

3

4

5

6

45 55 65 75 85 95 105 115

Age (Ma)

45

55

65

75

85

95

105



A g e ( M a )

Youngest Age Peak





60

0 20 40 60 80 100


A p p a r e n t A

g e ( M a )

40

45

50

55



Ar36







tion as the 1047298





















7 Conclusions








Acknowledgments



Box Canyon



at apex of teeth









Lamanonia sp Vell










X1


6 basal veins



X3








X5 (Juglandaceae)



X6








X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7






















































311 Description




312 Interpretation


Table 1







































321 Description



322 Interpretation






331 Description



335

340

345

350

355

360

365

370

375

380

SmStSpSh

Sh

SmStSh

ShSm

Sm

ShSm

StSmShSm

SmSh

FslFscSh

Sh

SmSh

Fsc

Smv

SmFsc

SmShSmv

s g cbf c

50

55

60

65

70

75

80

85

90

95

100

Gcmi

Gcmi

(174 cm)

Gcm

Gcm

(124 cm)

Gcmi

(135 cm)

s g cbf c

500

505

510

515

520

525

530

535

540

545

550

s g cbf c

SmSrSt

FmmFsc

Sm

StSr

Fsc

Fsc

FscCoal

St

Fsc

Gcm

Gcm

Gcm

Gcm

GcmSm

Sm

Gcm

Gcm

Sm

Covered

Fsc

FscCoal

St

A B C

St

Fsc

Fsc

tuffaceous

SrSt







332 Interpretation



341 Description



342 Interpretation









Arbitrary Base

10 cm

20 cm

30 cm

40 cm

50 cm

60 cm

70 cm

coarsesandstone

1-5 cm coalified

wood fragments


fossil seeds

leaves

purplebrown mottled

claystone

heavily weathered


siltstone varves

microbial horizons


soil at quarry top

Clay Silt Sand



















scale bars 10 mm












LMA LMAT C


eth1THORN

PLMA LMAT C


eth2THORN



r

r eth3THORN

















Table 2


Run MAT(degC)

WMMT(degC)

CMMT(degC)

LGS(months)

GSP(cm)

MMGSP(cm)

3WET(cm)

3DRY (cm)

RH()

SH(gkg)

ENTHAL (kJkg)

1 1136 2079 284 675 6221 1017 3821 2197 709 749 30522 1167 2125 303 688 7024 1007 3979 1959 7004 718 30453 1157 2102 272 69 6978 101 5162 152 7508 75 31414 1184 2145 291 699 7315 1019 5183 1513 7363 729 3137









Table 3



(references)


(degC)

MAP estimate

(cm)


92 127 114ndash149 121


94 76 11ndash146 1546






























6 Discussion





0

5

10

15

20

25

30

40 60 80 100 120 140 160 180 200 220


Ma


N


0

2

4

6

8

50 Ma 55 Ma 60 Ma



44

48

52

56

60

64

A g e

( M a )


of sample

0

1

2

3

4

5

6

45 55 65 75 85 95 105 115

Age (Ma)

45

55

65

75

85

95

105



A g e ( M a )

Youngest Age Peak





60

0 20 40 60 80 100


A p p a r e n t A

g e ( M a )

40

45

50

55



Ar36







tion as the 1047298





















7 Conclusions








Acknowledgments



Box Canyon



at apex of teeth









Lamanonia sp Vell










X1


6 basal veins



X3








X5 (Juglandaceae)



X6








X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7



















































321 Description



322 Interpretation






331 Description



335

340

345

350

355

360

365

370

375

380

SmStSpSh

Sh

SmStSh

ShSm

Sm

ShSm

StSmShSm

SmSh

FslFscSh

Sh

SmSh

Fsc

Smv

SmFsc

SmShSmv

s g cbf c

50

55

60

65

70

75

80

85

90

95

100

Gcmi

Gcmi

(174 cm)

Gcm

Gcm

(124 cm)

Gcmi

(135 cm)

s g cbf c

500

505

510

515

520

525

530

535

540

545

550

s g cbf c

SmSrSt

FmmFsc

Sm

StSr

Fsc

Fsc

FscCoal

St

Fsc

Gcm

Gcm

Gcm

Gcm

GcmSm

Sm

Gcm

Gcm

Sm

Covered

Fsc

FscCoal

St

A B C

St

Fsc

Fsc

tuffaceous

SrSt







332 Interpretation



341 Description



342 Interpretation









Arbitrary Base

10 cm

20 cm

30 cm

40 cm

50 cm

60 cm

70 cm

coarsesandstone

1-5 cm coalified

wood fragments


fossil seeds

leaves

purplebrown mottled

claystone

heavily weathered


siltstone varves

microbial horizons


soil at quarry top

Clay Silt Sand



















scale bars 10 mm












LMA LMAT C


eth1THORN

PLMA LMAT C


eth2THORN



r

r eth3THORN

















Table 2


Run MAT(degC)

WMMT(degC)

CMMT(degC)

LGS(months)

GSP(cm)

MMGSP(cm)

3WET(cm)

3DRY (cm)

RH()

SH(gkg)

ENTHAL (kJkg)

1 1136 2079 284 675 6221 1017 3821 2197 709 749 30522 1167 2125 303 688 7024 1007 3979 1959 7004 718 30453 1157 2102 272 69 6978 101 5162 152 7508 75 31414 1184 2145 291 699 7315 1019 5183 1513 7363 729 3137









Table 3



(references)


(degC)

MAP estimate

(cm)


92 127 114ndash149 121


94 76 11ndash146 1546






























6 Discussion





0

5

10

15

20

25

30

40 60 80 100 120 140 160 180 200 220


Ma


N


0

2

4

6

8

50 Ma 55 Ma 60 Ma



44

48

52

56

60

64

A g e

( M a )


of sample

0

1

2

3

4

5

6

45 55 65 75 85 95 105 115

Age (Ma)

45

55

65

75

85

95

105



A g e ( M a )

Youngest Age Peak





60

0 20 40 60 80 100


A p p a r e n t A

g e ( M a )

40

45

50

55



Ar36







tion as the 1047298





















7 Conclusions








Acknowledgments



Box Canyon



at apex of teeth









Lamanonia sp Vell










X1


6 basal veins



X3








X5 (Juglandaceae)



X6








X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7




















































332 Interpretation



341 Description



342 Interpretation









Arbitrary Base

10 cm

20 cm

30 cm

40 cm

50 cm

60 cm

70 cm

coarsesandstone

1-5 cm coalified

wood fragments


fossil seeds

leaves

purplebrown mottled

claystone

heavily weathered


siltstone varves

microbial horizons


soil at quarry top

Clay Silt Sand



















scale bars 10 mm












LMA LMAT C


eth1THORN

PLMA LMAT C


eth2THORN



r

r eth3THORN

















Table 2


Run MAT(degC)

WMMT(degC)

CMMT(degC)

LGS(months)

GSP(cm)

MMGSP(cm)

3WET(cm)

3DRY (cm)

RH()

SH(gkg)

ENTHAL (kJkg)

1 1136 2079 284 675 6221 1017 3821 2197 709 749 30522 1167 2125 303 688 7024 1007 3979 1959 7004 718 30453 1157 2102 272 69 6978 101 5162 152 7508 75 31414 1184 2145 291 699 7315 1019 5183 1513 7363 729 3137









Table 3



(references)


(degC)

MAP estimate

(cm)


92 127 114ndash149 121


94 76 11ndash146 1546






























6 Discussion





0

5

10

15

20

25

30

40 60 80 100 120 140 160 180 200 220


Ma


N


0

2

4

6

8

50 Ma 55 Ma 60 Ma



44

48

52

56

60

64

A g e

( M a )


of sample

0

1

2

3

4

5

6

45 55 65 75 85 95 105 115

Age (Ma)

45

55

65

75

85

95

105



A g e ( M a )

Youngest Age Peak





60

0 20 40 60 80 100


A p p a r e n t A

g e ( M a )

40

45

50

55



Ar36







tion as the 1047298





















7 Conclusions








Acknowledgments



Box Canyon



at apex of teeth









Lamanonia sp Vell










X1


6 basal veins



X3








X5 (Juglandaceae)



X6








X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7































































scale bars 10 mm












LMA LMAT C


eth1THORN

PLMA LMAT C


eth2THORN



r

r eth3THORN

















Table 2


Run MAT(degC)

WMMT(degC)

CMMT(degC)

LGS(months)

GSP(cm)

MMGSP(cm)

3WET(cm)

3DRY (cm)

RH()

SH(gkg)

ENTHAL (kJkg)

1 1136 2079 284 675 6221 1017 3821 2197 709 749 30522 1167 2125 303 688 7024 1007 3979 1959 7004 718 30453 1157 2102 272 69 6978 101 5162 152 7508 75 31414 1184 2145 291 699 7315 1019 5183 1513 7363 729 3137









Table 3



(references)


(degC)

MAP estimate

(cm)


92 127 114ndash149 121


94 76 11ndash146 1546






























6 Discussion





0

5

10

15

20

25

30

40 60 80 100 120 140 160 180 200 220


Ma


N


0

2

4

6

8

50 Ma 55 Ma 60 Ma



44

48

52

56

60

64

A g e

( M a )


of sample

0

1

2

3

4

5

6

45 55 65 75 85 95 105 115

Age (Ma)

45

55

65

75

85

95

105



A g e ( M a )

Youngest Age Peak





60

0 20 40 60 80 100


A p p a r e n t A

g e ( M a )

40

45

50

55



Ar36







tion as the 1047298





















7 Conclusions








Acknowledgments



Box Canyon



at apex of teeth









Lamanonia sp Vell










X1


6 basal veins



X3








X5 (Juglandaceae)



X6








X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7


























































LMA LMAT C


eth1THORN

PLMA LMAT C


eth2THORN



r

r eth3THORN

















Table 2


Run MAT(degC)

WMMT(degC)

CMMT(degC)

LGS(months)

GSP(cm)

MMGSP(cm)

3WET(cm)

3DRY (cm)

RH()

SH(gkg)

ENTHAL (kJkg)

1 1136 2079 284 675 6221 1017 3821 2197 709 749 30522 1167 2125 303 688 7024 1007 3979 1959 7004 718 30453 1157 2102 272 69 6978 101 5162 152 7508 75 31414 1184 2145 291 699 7315 1019 5183 1513 7363 729 3137









Table 3



(references)


(degC)

MAP estimate

(cm)


92 127 114ndash149 121


94 76 11ndash146 1546






























6 Discussion





0

5

10

15

20

25

30

40 60 80 100 120 140 160 180 200 220


Ma


N


0

2

4

6

8

50 Ma 55 Ma 60 Ma



44

48

52

56

60

64

A g e

( M a )


of sample

0

1

2

3

4

5

6

45 55 65 75 85 95 105 115

Age (Ma)

45

55

65

75

85

95

105



A g e ( M a )

Youngest Age Peak





60

0 20 40 60 80 100


A p p a r e n t A

g e ( M a )

40

45

50

55



Ar36







tion as the 1047298





















7 Conclusions








Acknowledgments



Box Canyon



at apex of teeth









Lamanonia sp Vell










X1


6 basal veins



X3








X5 (Juglandaceae)



X6








X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7























































Table 3



(references)


(degC)

MAP estimate

(cm)


92 127 114ndash149 121


94 76 11ndash146 1546






























6 Discussion





0

5

10

15

20

25

30

40 60 80 100 120 140 160 180 200 220


Ma


N


0

2

4

6

8

50 Ma 55 Ma 60 Ma



44

48

52

56

60

64

A g e

( M a )


of sample

0

1

2

3

4

5

6

45 55 65 75 85 95 105 115

Age (Ma)

45

55

65

75

85

95

105



A g e ( M a )

Youngest Age Peak





60

0 20 40 60 80 100


A p p a r e n t A

g e ( M a )

40

45

50

55



Ar36







tion as the 1047298





















7 Conclusions








Acknowledgments



Box Canyon



at apex of teeth









Lamanonia sp Vell










X1


6 basal veins



X3








X5 (Juglandaceae)



X6








X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7
































































6 Discussion





0

5

10

15

20

25

30

40 60 80 100 120 140 160 180 200 220


Ma


N


0

2

4

6

8

50 Ma 55 Ma 60 Ma



44

48

52

56

60

64

A g e

( M a )


of sample

0

1

2

3

4

5

6

45 55 65 75 85 95 105 115

Age (Ma)

45

55

65

75

85

95

105



A g e ( M a )

Youngest Age Peak





60

0 20 40 60 80 100


A p p a r e n t A

g e ( M a )

40

45

50

55



Ar36







tion as the 1047298





















7 Conclusions








Acknowledgments



Box Canyon



at apex of teeth









Lamanonia sp Vell










X1


6 basal veins



X3








X5 (Juglandaceae)



X6








X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7




















































tion as the 1047298





















7 Conclusions








Acknowledgments



Box Canyon



at apex of teeth









Lamanonia sp Vell










X1


6 basal veins



X3








X5 (Juglandaceae)



X6








X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7






















































7 Conclusions








Acknowledgments



Box Canyon



at apex of teeth









Lamanonia sp Vell










X1


6 basal veins



X3








X5 (Juglandaceae)



X6








X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7























































Lamanonia sp Vell










X1


6 basal veins



X3








X5 (Juglandaceae)



X6








X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7




















































X1


6 basal veins



X3








X5 (Juglandaceae)



X6








X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7




















































X5 (Juglandaceae)



X6








X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7


















































X8


from X2 and X5

X9


X11


X12


X13


morphotype from X7
















































palaeogeography, palaeoclimatology, palaeoecology

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