sp
Qls
Qls
Qls
cs
cs
cs
cs
cs
cs
vs
cs
cs
cs
cs
vs
cs
cs
Qls
QlsQls
Qls
Qls
Qls
sp
sp
sp
v
b
v
un
Qls
Qls
vsp
sp
sp
sp
Qls
sp
sp
sp Qls
vh
ch
fmh
fmh
fmh
v
v
Qt
Qal
Qt
Qt
Qt
QtQt
Qls Qls
Qls
QlsQls
vh
vhch
ch
vh
vh
Qt
fhmv
fmc
fmc
fmc
fmc
fmc
fmc
fmc
fmc
fmc
fmc
fmc
sp
sp
sp
Qls
Qls
fmc
fmc
fmc
Qls
Qls
sp
sp
vss
Qls
fhm
fhm
fhm
fhm
Qls Qls
fsm
Qls
Qls
Qls
ch
Qls
Qls
ch
ch
sp
spsp
fmc
fhm
fsm
fsm
Qls
Qls
QalQls
Qls
Qls
Qls
vs
v
vs
vs
vs
cs
Qls
Qfy
Qoa
QoaQtvo
Qls
Qto
Qoa
Qoa
Qoa
Qtvo
Qtvovsr
KJsr
KJsr
KJsr
KJsr
spsr
spsr
Qoa
Qoa
vsr
csr
Qsn
Qsn
spsr
spsr
Qls
Qls
KJsr
sp
sp
sp
sp
Qto
Qto
Qto
QtoQto
Qto
Qal
Qal
fmc
flpm
Qal
sp
vh
ch
vh
Qal
Qls
sp
vh
sp
sp
Qal
fhm
fhmsp
db
v
s
v
Qls
Qls
Qls
fmc
fmcfmc
fmcv
v
un
un
un
v
vb
c
v
fmc
v
um
vb
Qal
fsb
fsb
fsb
fmp
Qls
sp
sp
sp
sp
fmc
spvb
vm cm
c
vb
vb
un
g
b v
sv
cv vsp
cfmc
fmcfmc
fmc
fmc
fmc
Qls
ch
vh
chvh
chvh
un
fmc
fmc
un
Qls
Qls
Qls
Qls
Qls
QlsQls
Qls
Qls
Qls
Qls
Qt
Qt
Qt
sp
sp
sp fsm
sp
bv vh
Qls
QtQtvh
Qt
Qt
sp
Qt
v
Qtvo
Qtvo
QfoQfy
Qfy
Qal QalQto
Qto
Qto
Qto
Qto
Qto
Qal
spsr
spsr
vsr
spsr
spsr
spsr
spsr spsr
Qal sp
Qfvo
Qfvo
Qfvo
Qfvo
QfvoQfo
Qfvo
Qfvo
Qoa
Qoa
Qfvo
Qt
Qfo
fmcfmc
fmc
QtvoQty
Qfo
Qfo
Qfo
QtoQty
Qfo
QfoQal
Qal
Qal
Qls
spsr
sp
QtoQto
QtoQty
spQfo
Qfo
Qal
sp
sp
vh
vh
ssQls
Qls
Qls
vQt
Qt
Qt
v
v
sp
sp
sp
sp
ss
sp
Qal
cs
ch
vh
cs
vsr
vsr
Qal
fmp
sp
Qto
QtoQto
Qto
Qls
Qls
sp
Qto
Qt
Qt
sp
vb
db
mi
mi
Qt
sp
77
61 6145
33
58
80
85
8072
85
52
56
46 35
60
79 29
24
78
6052
70
5053
58
5277
52 7560
70
35
83
56
78
65
42
66
64
56
67
69
74
6170
57
65
75
71
20 52
54
62
69
32
7419
70
27 46
63
68
6064
61
23
73
52
50
46
70
45
45
66
32
62
6682
71
3861
32
28
21
70
43 84
5856 63
4577
28
60
47
60
37
89
41
67
54 63
7945 23
70
73
63
53
85
22 66 59
50
17
20
40 45
6538
18 23
70
25
38 63
7055
22 13
1320
60
71
16 5
34
4050
34
16
20 30
50
66
63
81 48 72
66
81
84
82 25
79
7560
30
8170
75
65
35
35
3545
50
74
65
60
60
7
40
76 5060
65
69
5571
26 3054
52
56
510
71
49
8065 43
4575
44
80
74
20
8553
25
50
30
48
4574
3018
60
60
50
6244
55
60
55
28
65
55
65
3030 20
3518
25
45
25
50
50
50
55
65 75
75
80
80
20 40 50
26
62
54
17
3653
36
55 45 6050 37
57
37
56
35
6
5
4
3
2
1
Elk Creek Segment
EastFlank Thrust
Thatcher Butte Fault
Logan SpringFault
Zone
Elk Creek Segment
Elk Creek Segment
Board Ridge Thrust
Foot Trail Fault
Boardman
RidgeFault Zone
Foot Trail Fault
Logan Spring
Fault Zone
Elk Creek Segment
Boardman Ridge Fault Zone
Eel River Segment
Foot Trail Fault
Southwest Ericson Ridge Fault
Boardman
RidgeFault Zone
Elk Creek Segment
Crocker Creek Fault
SanhedrinCreek
Fault
Northeast Ericson Ridge Fault
Board Ridge Thrust
Thatcher Butte Fault
East Flank Thrust
Thatcher Butte Fault
Rocky Point Segment
Elk Creek Segment
Chimney Rock Shear Zone
SquawCreek
Fault Zone
SquawCreek Fault Zone
SquawCreek Fault Zone
SquawCreek Fault Zone
Forks Creek FaultForks Creek Fault
TheIsland
Segment
TheIsland
Segment
Elk Creek Segment
Elk Creek Segment
ElkC
reek Segment
The Island Segment
Board Ridge Thrust
McLeod Ridge FaultMen
docin
o Pas
s Th
rust
DESCRIPTION OF MAP UNITSLandslide deposits (Holocene and late Pleistocene)mdashUnsorted unconsoli-
dated to weakly consolidated rock and soil debris which has moved downslope by various landslide processes including rotational slumping surface creep flowage or combinations thereof Earth flows are common in meacutelange of the Central Belt of the Franciscan Complex
Alluvium (Holocene and Pleistocene)mdashPoorly sorted unconsolidated sand silt gravel and boulders deposited in and adjacent to active stream channels
Alluvial stream terrace deposits undivided (Holocene and Pleistocene)-Poorly sorted weakly consolidated sand silt gravel and boulder deposits slightly dissected deposited along or adjacent to major streams Locally divided into
Young alluvial stream terrace deposits and surfaces (Holocene and late Pleistocene)mdashStream terraces that are least dissected and elevated above the active stream channel unit is delineated by geomorphic expression of terrace surfaces and in places does not include alluvial deposits
Old alluvial stream terrace deposits and surfaces (Pleistocene)-Alluvial terrace deposits that are elevated above dissected and incised by young alluvial terrace and fan deposits Includes as many as six stepped geomorphic surfaces that occur around margins of Lake Pillsbury basin at elevations between 1800 and 1920 ft
Very old alluvial stream terrace deposits and surfaces (Pleistocene)-Alluvial stream terrace remnants that include several stepped geomor-phic terrace surfaces that occur between elevations of 2000 and 2700 ft
Alluvial fan deposits and surfaces (Holocene and late Pleistocene)
Young alluvial fan deposits and surfaces (Holocene and late Pleistocene)mdashPoorly sorted weakly consolidated sand silt gravel and boulder deposits of alluvial fan systems at different elevations inset into older deposits distributed around north and east margins of Lake Pillsbury basin At least two young alluvial fan surfaces occur between the northern shoreline of Lake Pillsbury and elevation 1920 ft
Old alluvial fan deposits and surfaces (Pleistocene)mdashAlluvial fan deposits that are elevated dissected and incised by younger fans and alluvial terrace deposits At least five stepped old alluvial fan surfaces are recognized around the north and east sides of Lake Pillsbury basin at elevations between 1900 and 2000 ft
Very old alluvial fan deposits and surfaces (Pleistocene)-Topographically high dissected and uplifted alluvial fan deposits including as many as four stepped fan surfaces mapped at elevations between 2040 and 2100 ft along northeast side of Lake Pillsbury basin
Older alluvial deposits undivided (Pleistocene)mdashWeakly consolidated moderately organized to unorganized weakly sorted to unsorted silt sand and gravel deposits that locally display clast imbrication crossbed-ding and channels moderately to extremely dissected present along the east and west sides of Lake Pillsbury basin and east side of Gravelly Valley Unit includes deposits characteristic of alluvial fan and braided-stream depositional settings locally including massive lacustrine() mudstone beneath old terraces (Qto) along west edge of Lake Pillsbury Along east and west sides of Lake Pillsbury unit contacts are highly generalized and encompass significant unmapped bedrock particularly on steep slopes and in tributaries draining into reservoir In places unit may correlate with old strath terraces or thin old alluvial fan deposits cut on bedrock (Qto Qtvo Qfo Qfvo)
Siliceous and calcareous sinter deposits (Pleistocene)mdashVuggy opalitic and carbonate-veined and sheared serpentinite and argillitic microbrec-cia present locally along Logan Spring Fault southeast of Logan Spring probably related to extinct low temperature thermal seep activity
Great Valley Sequence (Cretaceous and Jurassic)Ophiolitic meacutelange and sedimentary rocks of Split Rock (Early
Cretaceous or younger)mdashA broken sequence of sandstone locally massive and conglomeratic thinly interbedded argillite and turbiditic arkosic wacke and mafic to ultramafic rocks Unit is in places penetra-tively deformed into block-in-matrix meacutelange comprised of mafic and ultramafic rocks with argillite and sandstone matrix elsewhere matrix is sheared serpentinite with blocks of sandstone and argillite chert and mafic igneous rocks derived from Coast Range Ophiolite Unit includes fossils of Late Jurassic (Tithonian) age within the map area (fossil localities 5 6) and Late Jurassic (Tithonian) to Early Cretaceous (Valanginian to Hauterivian) age outside of the map area to the SE Early Cretaceous or younger age assignment is based on timing of tectonic mixing of youngest meacutelange components southeast of map area (Berkland 1973 Blake and Jones 1974 McLaughlin and others 1990 Campbell and others 1993 Campbell and Bottjer 1995 Campbell and others 2002 Kiel and others 2008) The Ophiolitic meacutelange and sedimentary rocks of Split Rock are correlated with similar rocks east of the Bartlett Springs Fault ~ 53 km to the SE in the Wilbur Springs area (McLaughlin and others 1990) The unit locally includes blocksBlocks of mafic volcanic and plutonic rocksmdashIncluding basaltic flows and breccia diabase and gabbro
Blocks of chert
Blocks and lenticular bodies of ultramafic rock
Coast Range Ophiolite (Middle Jurassic)Ultramafic rocks and serpentinite of the Coast Range Ophiolite
(Jurassic)mdashLenticular masses of tectonized dunite periodite and pyroxenite in a sheared matrix of serpentine minerals North of Bear Creek includes gabbroBlocks of gabbro
Franciscan Complex (Early Tertiary() - Jurassic)Central Belt
Diabase intrusive into meacutelange of the Central Belt (Late Cretaceous or younger)mdashDiabase dikes and sills intrusive into meacutelange in northern part of map area Although intrusive into and thus younger than the meacutelange these diabase intrusives are here considered an integral element of the formational setting of the Central BeltMeacutelange of the Central Belt (Early Tertiary or Late Cretaceous)mdashA penetratively sheared chaotic mixture of rocks with a matrix largely of sheared argillite and metasandstone that encloses outcrop to map-scale blocks and slabs of interbedded argillite and metasandstone Matrix rocks are regionally metamorphosed to pumpelly-ite- and incipient lawsonite-grade and reconstituted to textural zone 1 of Blake and others (1967) Outside of the map area fossiliferous blocks in meacutelange of the Central Belt contain mollusks and ammonites of Late Jurassic (Tithonian) to Early Cretaceous (Late Valanginian) age (Blake and Jones 1974) foraminifera of Middle to Late Cretaceous (Aptian ndashConiacian) age (Sliter 1984) and dinoflagellates of Late Jurassic
(Tithonian) to Middle Cretaceous (Albian or Aptian) age (Lucas-Clark 2007) Radiolaria from a chert block in the map area (fossil locality 2 table 1) are Late Jurassic (Tithonian) in age Radiolarian ages from cherts elsewhere in the Central Belt (McLaughlin and Pessagno 1978 Murchey and Jones 1984) range from early Jurassic (Pliensbachian) to early Late Cretaceous (Cenomanian) White mica from blocks of blueschist gives potassium-argon ages of 151 to 155 my (Lehman 1974) A block of diorite from ONeil Ridge that has undergone pumpel-lyite grade metamorphism gives a Pb-U age of 161 my (J Mattinson written commun 1982) The inferred age of meacutelange-forming tectonic mixing based on the ages of youngest meacutelange components is Conia-cian or younger north of the map area and Campanian or younger (possibly Eocene or younger) south of the map area Individual blocks and slabs in the meacutelange comprise
MetasandstonemdashTextural zone 1 metamorphosed to pumpellyite grade or lower
ChertmdashIncludes relatively unmetamorphosed chert and blocks that are highly metamorphosed and reconstituted texturally containing blueschist minerals (stilpnomelane sodic amphibole or lawsonite)
Mafic volcanic rocksmdashMostly metamorphosed to low greenschist (epidote-pumpellyite) grade locally includes more highly metamor-phosed texturally reconstituted blocks of blueschist grade that contain jadeite sodic amphibole and (or) lawsonite
Blueschist and associated rocksmdashHigh-grade blocks of glaucophane schist eclogite and garnet amphibolite
Blocks of unknown compositionmdashMapped from air photos Eastern Belt (Cretaceous and Jurassic)
Yolla Bolly Terrane
Metasedimentary rocks of Sanhedrin Mountain (Cretaceous and Jurassic)mdashComposed of fine- to coarse-grained thin-to medium-bedded metasandstone reconstituted to textural zone 2 of Blake and others (1967) with sheared interbedded argillite Quartzofeldspathic sandstone predominates in the northeastern part of the unit with local sheared lenses of conglomerate and tuffaceous greenstone Higher on Sanhedrin Mountain metasandstone with a high percentage of lithic grains occurs with abundant thick manganiferous metachert lenses and less common metavolcanic rocks including tuff pillow basalt volcanic breccia and diabase Unit may include minor thin zones of undivided meacutelange in a few areas as suggested by a few areas with scattered blocks of high-grade blueschist and serpentinite
Blocks and intercalated lenses of metavolcanic rocks
Blocks and lenses of metachert associated with metavolcanic rocksIntrusive rocks of Monkey Rock (Cretaceous)mdashMetagabbroic dike
and sill-like bodies intrusive into metasandstone and argillite of Hull Mountain
Metasandstone of Hull Mountain (Cretaceous)mdashThe Metasand-stone of Hull Mountain consists largely of structurally stacked slabs of broken formation possibly with minor undivided zones of meacutelange (suggested by a few scattered blocks of blueschist or serpentinite) The broken formation of these stacked slabs is composed largely of fine-grained thin-bedded lithic metasandstone and interbedded argillite well-bedded medium- to coarse-grained lithic metasandstone and intercalations of chert pebble conglomerate grit and rare lenses of volcanic rock and chert Unit locally includes zones of broken metasand-
stone and argillite with abundant lenses and blocks of interleaved radiolarian chert and porphyritic pillow basalt and tuff Radiolarian fauna from the chert lenses indicates an Early Cretaceous age in the report area (fossil locality 4) Locally overlying this chert is well-bedded medium- to coarse-grained lithic metasandstone with interbeds of chert pebble conglomerate grit and rare lensoid bodies of tuffaceous volcanic rock and chert The structurally highest part of the Metasandstone of Hull Mountain consists of a broken unit of metasandstone and sheared argillite containing a molluscan fauna of Cenomanian age (fossil locality 3) All the metasandstone is reconstituted to Textural Zones 1 to 2 of Blake and others (1967) containing the blueschist mineral assemblage (lawsonite + white mica plusmn sodic amphibole plusmn jadeite plusmn pumpellyite) Chert and volcanic rocks are also metamorphosed to blueschist grade containing lawsonite plusmn sodic amphibole plusmn jadeite Where mapped unit includes following blocks
Blocks of unknown compositionmdashMapped from air photos
Blocks and interleaved lenses of chert
Blocks and interleaved lenses of metavolcanic rocksPickett Peak Terrane()
Metasedimentary rocks of Mendocino Pass (Early Cretaceous)-Composed of slightly sheared fine- to medium-grained thin- to medium- bedded metasandstone reconstituted to textural zone 2 of Blake and others (1967) interbedded with black argillite Metasandstone beds are locally graded and interbedded chert and greenstone lenses are present at one locality Metasandstone includes Valanginian Buchias at one locality (fossil locality 1 table 1) This unit is distinguished by development of a moderate foliation in contrast with structurally overlying schistose metamorphic rocks of Black Butte and Bald Mtn and by its intact coherent aspect in contrast with structurally underlying disrupted rocks in meacutelange of the Central Belt Unit may correlate with Valantine Spring Formation unit of Pickett Peak Terrane (Blake and others 1992) East of Bald Mountain unit includes the following units
Metachert lens interbedded with metagreenstone
Metagreenstone lens interbedded with metachertPickett Peak Terrane
Metamorphic rocks of Black Butte and Bald Mountain (Early Cretaceous)mdashMetasandstone metamorphosed to lawsonite grade and reconstituted to textural zones 2 and 3 of Blake and others (1967) In the Bald Mountain area unit consists of medium- to coarse-grained metasandstone with lenses of stretched-pebble conglomerate that structurally overlies finer grained well-laminated and foliated metasand-stone and argillite with blocks of mafic metavolcanic rocks and metagab-bro Radiometric dating of metasandstone in the Black Butte area (Suppe 1969) yielded K-Ar ages for metamorphism of the unit of 123 to 127 my
Blocks of unknown compositionmdashMapped from air photos
Metavolcanic rocksmdashBlocks of mafic metavolcanic and metagab-broic rocks possibly intrusive locally Metavolcanics are more abundant and varied to the north of map area
Metamorphic rocks of Lake Pillsbury (Early Cretaceous)-Foliated fine-grained pelite and metasandstone (Textural Zone 3 to high Textural Zone 2 of Blake and others 1967) and rare intercalated mafic
metavolcanic rocks Questionably correlated with the South Fork Moun-tain schist of the Pickett Peak terrane of the Eastern Belt (Blake and others 1982 Irwin and others 1974) by Etter (1979) Unit was considered by Etter (1979) to have been metamorphosed to blueschist grade ~137 Ma based on a whole-rock K-Ar age for the metasandstone (Suppe and Foland 1978) A recent PbU age on detrital zircons from these rocks provides a depositional age of 123 Ma and an 40Ar39Ar determination on phengitic white mica provides a metamorphic age of about 120 Ma (Dumitru and others 2009) The Pb-U and 40Ar39Ar ages are here considered more reliable than the older K-Ar ages
EXPLANATION OF MAP SYMBOLSContactmdashSolid where location is accurate long-dashed where approximate
dotted where concealedPhotolineament marking resistive beddingFaultmdashSolid where location is accurate long-dashed where approximate
short-dashed where inferred dotted where concealed Queries added where identity or existence may be questionable
Fault ScarpmdashShowing fault line at base of scarp with hachure pointing up slope
Thrust faultmdashSolid where location is accurate long-dashed where approxi-mate short-dashed where inferred dotted where concealed Sawteeth on upper plate
Fault lineamentmdash Inferred from features on aerial photography dotted where projected beneath surficial deposits queried where uncertain
Strike and dip of beds
Inclined
Overturned
Vertical
Strike and dip of metamorphic fabric in sheared or foliated rocks
Inclined
VerticalLocation of block or lens too small to map in broken formation or meacutelange
BlueschistSerpentiniteVolcanic rockChert
Fossil LocationmdashSee table 1 for fossil informationScott Dam
Qls
Qal
Qt
Qty
Qto
Qtvo
Qfy
Qfo
Qfvo
Qoa
Qsn
KJsr
vsr
csr
spsr
sp
g
db
fmc
c
v
s
b
un
fsm
un
ch
mi
fmp
cm
vm
fsb
un
vb
vs
cs
fhm
flpm
vh
5
61
35
70
Qoa contacts may be over generalized in this area and include areas of bedrock exposed in -tributaries to the reservoir and on the steep slopes
Qoa contacts may be over generalized in this area and include areas of bedrock exposed in
-
tributaries to the reservoir and on the steep slopes
Lacustrine() mudstone
sp diapir intrudingQfo deposit
Fault-creepleft-stepped dextralcracks in pavement
C
D E
7000
6000
5000
4000
3000
2000
7000
6000
5000
4000
3000
2000
ELEV
ATIO
N (f
eet)
A B Bend C Bend D Bend E
fsm
fsm
fmcfmc
sp
sp
cs
fsmfsm
Qls
fhm fhm fhmfhm
fhmfhm
fhm
g
ch
vhvh
Qt QtQlsvv
v
sp QlsQls
spsp
vv
ssdb
fmc
fmc
fsbvb vb fsb
fmp
cmvm
fmp
fsbspfsb
spFOO
TTR
AIL
FAU
LT
CR
OC
KER
CR
EEK
FAU
LT
BARTLETT SPRINGS FAULT ZONE
FOR
KS C
REE
K FA
ULT
ELK
CR
EEK
SEG
MEN
T
Elk
Cre
ek
Bea
r Cre
ek
THAT
CH
ER
BUTT
E FA
ULT
Swallow Rock
Bald Mountain
EAST FLANK THRUST
BOARD RIDGE THRUST
MENDOCINO PASS THRUST
ch
A
B
Qls Qfy
Qfo
Qfvo
Qal
Qty
Qto
Qtvo
CENTRAL BELT
cm
mi
Qt
Qoa
KJsr
csr
fmc
ch cs
fhm
vhvs
fmp
vm
vb
s
g
sp
COAST RANGE OPHIOLITE
CORRELATION OF MAP UNITS
fsm
Holocene
PleistoceneQUATERNARY
CRETACEOUS
CRETACEOUS AND (OR) JURASSIC
EARLY TERTIARY
un
un
Qsn
QUATERNARY DEPOSITS
GREAT VALLEYSEQUENCE
Yolla Bolly terrane
FRANCISCAN COMPLEX
Pickett Peak terranePickett Peak terrane()
EASTERN BELT
db db
JURASSIC
c
v
b
un
vsr
spsr
fsb flpm
1 Ohlin HN mapping and air photo reconnaissance 1980-19822 CDWR 19693 Lehman DH 19744 Jordan MA 19745 Etter SD 19796 Layman EB 19777 Sawyer TL fieldwork 2008-20098 Lienkaemper JJ and Brown 20099 McLaughlin RJ reconnaissance field work 2009
SOURCES OF GEOLOGIC MAP DATA
9
122deg5230W123deg00W123deg730W
39deg300N
39deg2230N
39deg3730N
18
16
155
13
1248
578
9
5
5
122deg5230W123deg00W123deg730W
39deg300N
39deg2230N
ECS
ECS
ERFERF
RPS
ERS
TIS
FTF
CCFEFT
SCFZBRF
GVS
FCF
SCF
BRT
LSFZ
EWF
MRF
TBF CRSZ
39deg3730N
MAJOR FAULTS OF THE LAKE PILLSBURY REGION
Main Bartlett Springs Fault Zone Elk Creek Segment- ECS The Island Segment- TIS Gravelly Valley (creeping) Segment- GVS Eel River Segment- ERS Rocky Point Segment- RPS
Southwestern Bartlett Springs Fault Zone Sanhedrin Creek Fault- SCF Northeast and Southwest Ericson Ridge Faults- ERF Logan Spring Fault Zone- LSFZ
Low-angle Faults Board Ridge Thrust- BRT East Flank Thrust- EFT
Other Faults Chimney Rock Shear Zone- CRSZ Thatcher Butte Fault- TBF Forks Creek Fault- FCF Crocker Creek Fault- CCF Foot Trail Fault- FTF Boardman Ridge Fault Zone- BRF Squaw Creek Fault Zone- SCFZ McLeod Ridge Fault- MRF East-West Faults- EWF
Base from US Geological Survey Lake Pillsbury 1994Hull Mountain 1973 and Sanhedrin Mountain 1994Lake Pillsbury Bathymetry from Pacific Gas and Electricitic Company 2005 Universal Transverse Mercator projection Zone 11
7000 FEET1000 10000 2000 3000 4000 5000 6000
5 1 KILOMETER1 0
SCALE 130000
1 21 0 1 MILE
CONTOUR INTERVAL 40 FEETDATUM IS MEAN SEA LEVEL
Geologic map of the Bartlett Springs Fault Zone in the Vicinity of Lake Pillsburyand Adjacent Areas of Mendocino Lake and Glenn Counties California
By
2010
Barry C Moring and Thomas L SawyerHenry N Ohlin 1 1 1 2Robert J McLaughlin
CALIF
MAP LOCATIONAPPROXIMATE MEANDECLINATION 2010
14 deg1 2
MAG
NET
IC N
OR
TH
TRU
E N
OR
TH
Open-File Report 2010-1301Pamphlet accompanies map
Any use of trade product or firm names in this publication is for descriptive purposes only and does not imply endorsement by the US Government
When this map is printed on an electronic plotter directly from digital file Dimensional calibration may vary between electronic plotters and between X and Y directions on the same plotter and paper may change size due to atmospheric conditions therefore scale and proportions may not be true on plots of this map
Digital files available at httppubsusgsgovof20101301
Suggested Citation Ohlin HN McLaughlin RJ Moring BC and Sawyer TL 2010 Geologic map of the Bartlett Springs Fault Zone in the Vicinity of Lake Pillsbury and Adjacent Areas of Mendocino Lake and Glenn Counties California US Geological Survey Open-File Report 2010-1301 scale 130000 [httppubsusgsgovof20101301]
US Department of the InteriorUS Geological Survey
Geology mapped by HN Ohlin 1980-1982 TL Sawyer 2007 revised RJ McLaughlin 2008-2009 GIS database and digital cartography by Barry C MoringEdited by Jan L Zigler
Manuscript approved for publication December 3 2010
1US Geological Survey 345 Middlefield Road Menlo Park CA 94025 Piedmont Geosciences Inc 10235 Blackhawk Drive Reno NV 89506-85272
122deg5230
122deg5230
123deg00W
123deg00W
123deg730W
123deg73039deg3730 39deg3730N
39deg300 39deg300
39deg2230N 39deg2230