Study AreaStudy Area

••Passive marginPassive margin

••SiliciclasticSiliciclastic

PaleoshorelinesPaleoshorelines

••FeatherFeather--edge edge updipupdip limit limit

of Pleistocene of Pleistocene

depositional sequencesdepositional sequences

••MicroMicro--tidaltidal

••Wave dominatedWave dominated

••300 km barrier island 300 km barrier island

chainchain

••Intermediate Field of GIA Intermediate Field of GIA

((LambeckLambeck, , ‘‘93)93)

Abstract:Abstract:

Improvements in Improvements in geochronologicalgeochronological techniques now techniques now

allow for more precise dating of allow for more precise dating of siliciclasticsiliciclastic coastal coastal

lithosomeslithosomes that have the potential to provide many that have the potential to provide many

more seamore sea--level index points (level index points (SLIPsSLIPs) for the ) for the

Quaternary Period. These techniques include Quaternary Period. These techniques include

optically stimulated luminescence (OSL) and electron optically stimulated luminescence (OSL) and electron

spin resonance dating (ESR). This investigation uses spin resonance dating (ESR). This investigation uses

these new dating tools in conjunction with ground these new dating tools in conjunction with ground

penetrating radar (GPR) and penetrating radar (GPR) and sedimentologicalsedimentological data to data to

establish the age and relative sea level (RSL) as establish the age and relative sea level (RSL) as

recorded by stranded coastal recorded by stranded coastal lithosomeslithosomes (Holocene (Holocene

and Pleistocene beach ridges, tidal flat and Pleistocene beach ridges, tidal flat faciesfacies, etc.) in , etc.) in

North Carolina and Florida. Sites have been cored North Carolina and Florida. Sites have been cored

using using vibracorevibracore and and geoprobegeoprobe techniques, sampled techniques, sampled

for for granulometricgranulometric and OSL analyses, and surveyed and OSL analyses, and surveyed

using GPR. These coastal deposits consist of using GPR. These coastal deposits consist of

siliciclasticsiliciclastic or mixed carbonate or mixed carbonate siliciclasticsiliciclastic sands. sands.

However, due to intense However, due to intense subaerialsubaerial leaching, the leaching, the

carbonate sediments are typically too badly altered, carbonate sediments are typically too badly altered,

or too scarce to acquire meaningful Uor too scarce to acquire meaningful U--series dates. series dates.

GranulometricGranulometric and GPR data are being used to and GPR data are being used to

indicate the elevation of the beachindicate the elevation of the beach--face face –– surf zone surf zone

transition, which provides a datum for determining transition, which provides a datum for determining

RSL. These data are being used to refine the RSL. These data are being used to refine the

Quaternary relative seaQuaternary relative sea--level record of the SEUS level record of the SEUS

Atlantic Coastal Plain and, by comparison to other Atlantic Coastal Plain and, by comparison to other

Quaternary seaQuaternary sea--level data and level data and isostaticisostatic models, will models, will

help to refine models of mantle and lithosphere help to refine models of mantle and lithosphere

rheologyrheology and and isostasyisostasy..

New Insights into Quaternary SeaNew Insights into Quaternary Sea--Level Fluctuations and Level Fluctuations and IsostasyIsostasy Based on Geophysical, Based on Geophysical, SedimentologicalSedimentological, and Optical Dating , and Optical Dating

Investigations of Investigations of PaleoPaleo--Shoreline Features on the Southeast U.S. Atlantic Coastal Plain.Shoreline Features on the Southeast U.S. Atlantic Coastal Plain.11David Mallinson, David Mallinson, 22Kevin Burdette, Kevin Burdette, 22Jack Rink, Jack Rink, 11Pete Parham, Pete Parham, 33Shannon Mahan, Shannon Mahan, 44Richard PeltierRichard Peltier

11Dept. of Geological Sciences, East Carolina University, GreenvilDept. of Geological Sciences, East Carolina University, Greenville, NC le, NC mallinsond@ecu.edumallinsond@ecu.edu22School of Geography and Earth Sciences, McMaster University, HamSchool of Geography and Earth Sciences, McMaster University, Hamilton, Ontarioilton, Ontario

33United States Geological Survey Optically Stimulated LuminescencUnited States Geological Survey Optically Stimulated Luminescence Laboratory, Denver, COe Laboratory, Denver, CO

44Dept. Of Physics, University of Toronto, Toronto, OntarioDept. Of Physics, University of Toronto, Toronto, Ontario

What are we doing?What are we doing?

In a nutshell, weIn a nutshell, we’’re attempting to date re attempting to date

Pleistocene and Holocene shoreline Pleistocene and Holocene shoreline

deposits using OSL, and define the deposits using OSL, and define the

depositional environments using depositional environments using

geophysics and geophysics and sedimentologysedimentology, to , to

determine relative seadetermine relative sea--level index points level index points

((SLIPsSLIPs) and understand the Quaternary ) and understand the Quaternary

evolution of the SEUS coastal systems.evolution of the SEUS coastal systems.

Why?Why?

To resolve questions regarding timing and To resolve questions regarding timing and

elevation of Pleistocene seaelevation of Pleistocene sea--level level

highstandshighstands, and , and glacioglacio--isostasyisostasy in the in the

intermediate field, and understand the intermediate field, and understand the

response of the coastal system to climate response of the coastal system to climate

and seaand sea--level changelevel change

Where?Where?

WeWe’’re working in eastern North Carolina re working in eastern North Carolina

and Florida.and Florida.

A) The study areas occur in the intermediate field of A) The study areas occur in the intermediate field of glacioglacio--isostasyisostasy. .

B) Rate of relative seaB) Rate of relative sea--level rise as a function of level rise as a function of forebulgeforebulge collapse (ICEcollapse (ICE--4G model 4G model

from Peltier, 2004). Study areas show rates of ca. 0.8from Peltier, 2004). Study areas show rates of ca. 0.8--2 mm/y.2 mm/y.

C) RSL rise is highest across the SEUS, with maximum rates in noC) RSL rise is highest across the SEUS, with maximum rates in northeast NC, and rtheast NC, and

southern VA.southern VA.

B C

A

HickoryHickory

LoPLoP, PP, PP

(see Figure below)(see Figure below)

Suffolk Suffolk

ShorelineShoreline

AB

C

D

A

B C

Numerous Numerous paleoshorelinespaleoshorelines and associated and associated

lithosomeslithosomes (tidal flat, shallow shelf, etc.) occur in (tidal flat, shallow shelf, etc.) occur in

NE NC. We are focusing on the Suffolk Shoreline, NE NC. We are focusing on the Suffolk Shoreline,

the Hickory Shoreline, the Land of Promise (the Hickory Shoreline, the Land of Promise (LoPLoP) )

and Powelland Powell’’s Point (PP) Shorelines, as well as the s Point (PP) Shorelines, as well as the

Holocene barrier island system (the Outer Banks).Holocene barrier island system (the Outer Banks).

Example of 2Example of 2--d GPR data acquired on d GPR data acquired on

West Merritt Island (southernmost West Merritt Island (southernmost

transect on B above). Vertical scale is transect on B above). Vertical scale is

based on a dielectric constant of 25.based on a dielectric constant of 25.

OSL, AAR and UOSL, AAR and U--series data indicate series data indicate

that the Suffolk Shoreline is a Stage that the Suffolk Shoreline is a Stage

5 (5e and 5a) feature, and that the 5 (5e and 5a) feature, and that the

Hickory, Hickory, LoPLoP and PP shorelines are and PP shorelines are

Stage 3, indicating present Stage 3, indicating present isostaticisostatic

uplift of ca. 20 to 25 m above the uplift of ca. 20 to 25 m above the

equilibrium profile (Mallinson et al., equilibrium profile (Mallinson et al.,

2008).2008).

LiDARLiDAR data of data of paleoshorelinepaleoshoreline

Features being investigatedFeatures being investigated

A)A) Hickory, Hickory, LoPLoP, and PP Shorelines, and PP Shorelines

B) and C) Suffolk ShorelineB) and C) Suffolk Shoreline

D) D) paleopaleo--cape featurecape feature

D

Ground penetrating radar (GPR) (200 MHz GSSI SIRGround penetrating radar (GPR) (200 MHz GSSI SIR--2000 2000

unit), unit), GeoprobeGeoprobe, , VibracoreVibracore, OSL dating, OSL dating

Florida Study Areas

A

A’

A

A’

Beach ridges/paleo-cape being investigated.

Red line indicates location of GPR data shown

at right.

ReferencesReferences

••CabiochCabioch, G., , G., AyliffeAyliffe, L.K., 2001. Quaternary Research 56, 357, L.K., 2001. Quaternary Research 56, 357--365.365.

••Chappell, J., Chappell, J., OmuraOmura, A., , A., EsatEsat, A., , A., McColluchMcColluch, T., , T., PandolfiPandolfi, M., , M., PillansPillans, J., 1996. Earth and , J., 1996. Earth and

Planetary Science Letters 141, 227Planetary Science Letters 141, 227--236.236.

••ImbrieImbrie, J., McIntyre, A., Mix, A. C., 1989. In, A. Berger, S. H. Schne, J., McIntyre, A., Mix, A. C., 1989. In, A. Berger, S. H. Schneider, and J.ider, and J.--C. C. DuplessyDuplessy, ,

(Eds.), Climate and Geosciences, A Challenge for Science and Soc(Eds.), Climate and Geosciences, A Challenge for Science and Society in the 21st Century, D. iety in the 21st Century, D.

ReidelReidel Publishing Company.Publishing Company.

••LinsleyLinsley, B.K., 1996. Nature 380, 234, B.K., 1996. Nature 380, 234--237, 237,

••Mallinson, D., Burdette, K., Mahan, S., Brook, G., 2008. QuaternMallinson, D., Burdette, K., Mahan, S., Brook, G., 2008. Quaternary Research 69, 97ary Research 69, 97--109.109.

••OpdykeOpdyke, N., Spangler, D., Smith, D., Jones, R., Lindquist, R., 1984. G, N., Spangler, D., Smith, D., Jones, R., Lindquist, R., 1984. Geology 12, 226eology 12, 226--228.228.

••Peltier, W. R., 2004. Rev. Earth Planet Peltier, W. R., 2004. Rev. Earth Planet SciSci. 32, 111. 32, 111--149.149.

••Potter, E.Potter, E.--K., K., LambeckLambeck, K., 2003. Earth and Planetary Science Letters, K., 2003. Earth and Planetary Science Letters 217, 171217, 171--181.181.

••Rink, W.J., Forrest, B., 2005. Journal of Coastal Research 21, 1Rink, W.J., Forrest, B., 2005. Journal of Coastal Research 21, 1000000--1009.1009.

••Winker and Howard, 1977. Geology 5, 123Winker and Howard, 1977. Geology 5, 123--127.127.

Study Areas

A

B

CA) Location of Florida Study A) Location of Florida Study

Areas. B) Map illustrating the Areas. B) Map illustrating the PlioPlio--

Quaternary shoreline sequences in Quaternary shoreline sequences in

Florida as defined by Winker and Florida as defined by Winker and

Howard (1977). C) Geologic Map Howard (1977). C) Geologic Map

showing specific site locations.showing specific site locations.

Hypothesized correlations of Florida Ridge Sequences to the mariHypothesized correlations of Florida Ridge Sequences to the marine ne

isotope stages based on a proposed 0.024 mm/y isotope stages based on a proposed 0.024 mm/y epeirogenicepeirogenic uplift uplift

rate (rate (OpdykeOpdyke et al., 1984).et al., 1984).

Aerial photographs Aerial photographs

((DOQQsDOQQs) of selected ) of selected

study areas (see above study areas (see above

right right –– Fig. 3aFig. 3a--3d 3d

locations). A) East locations). A) East

Merritt Island beach Merritt Island beach

ridges; B) West Merritt ridges; B) West Merritt

Island beach ridges; C) Island beach ridges; C)

RimaRima Ridge; D) Osceola Ridge; D) Osceola

StrandplainStrandplain. Green dots . Green dots

are waypoints taken are waypoints taken

during GPR surveys.during GPR surveys.

Top Top -- Location of the Location of the

proposed study area proposed study area

west of Apalachicola west of Apalachicola

Bay in the Florida Bay in the Florida

Panhandle. Bottom Panhandle. Bottom --

Aerial photograph Aerial photograph

showing the areas of showing the areas of

interest.interest.

OSL dates thus far corroborate UOSL dates thus far corroborate U--series dates, where series dates, where

available.available.

NC dates support a MIS 5 origin for the Suffolk Shoreline, NC dates support a MIS 5 origin for the Suffolk Shoreline,

MIS 3 (MIS 3 (aveave. ca. 51 ka) for Hickory, . ca. 51 ka) for Hickory, LoPLoP, and PP Shorelines, and , and PP Shorelines, and

ca. 3 to 2 ka for beach ridges at Kitty Hawk on the modern ca. 3 to 2 ka for beach ridges at Kitty Hawk on the modern

Outer Banks, and at Cape Canaveral (Rink and Forrest, 2005).Outer Banks, and at Cape Canaveral (Rink and Forrest, 2005).

Data are in general agreement with GIA models (Peltier, Data are in general agreement with GIA models (Peltier,

2004; Potter and 2004; Potter and LambeckLambeck, 2003), 2003)

GPR and GPR and sedimentologicalsedimentological data provide useful relative SL data provide useful relative SL

data.data.

Florida dates are pending; GPR data reveal the Florida dates are pending; GPR data reveal the beachfacebeachface

deposits, which will be used for Quaternary relative deposits, which will be used for Quaternary relative SLIPsSLIPs..

Acknowledgments: Significant contributions have been made byAcknowledgments: Significant contributions have been made by

Stephen Culver, Stan Riggs, John Wehmiller, and Kathleen FarrellStephen Culver, Stan Riggs, John Wehmiller, and Kathleen Farrell via a related via a related

USGS funded project. Thanks to John Woods and Jim Watson for asUSGS funded project. Thanks to John Woods and Jim Watson for assistance in sistance in

field. Numerous graduate students have also contributed. Data field. Numerous graduate students have also contributed. Data collected are collected are

being used for the Ph.D. dissertations of Kevin Burdette and Petbeing used for the Ph.D. dissertations of Kevin Burdette and Pete Parham, and e Parham, and

M.S. theses of Kelly Best and Katie McDowell (ECU).M.S. theses of Kelly Best and Katie McDowell (ECU).

Florida Florida geoprobegeoprobe

fun; collectingfun; collecting

Conductivity dataConductivity data

Peltier, 2004Peltier, 2004

Outer Banks

Tidal flat deposits beneath

Hickory Shoreline

OSL sample