Qya Qd Qoe Qhc Tmc Qye Tmb Tor Qb Qya Tot Qye Qya Tot Tor Tot af Tot Qya Tmc Tmc Tms Qye Qd Qye Qd Tor Tor Qoa Qoa Tot Tot Qoa Tpsq Tot Tms Tot Qd Qls af Tot Tor Qls Qoa Qls Qls af Qb af Tot Tot af Tot af Tor Tor Tor c Tot Tor Qye Tot af Tot Tor Qd Qya Tor Tpsq Tor Qm Qls Tor sp Tot Tot Qya Qm Qm Tot Tor Tot Qm Qm Qm Tor Qye Qye Qm Tor sp sp Qm? Tor Tor Tot Qm Tor Qye Qm mv sp Tor Qm? sp Tr? sp Tor sp Qoa Qm Tor Qm mv ch mv Qm? sp Qm sp Qm sp Tot Qm KJfm Qm Qm? Tor Qm mv Qm Qm Qm? Qm? Qm mv Qb Qb Qd Qd Qhc Qhc Qye Qya Qya Qya Qya Qya Qa KJfm water Tor Qls Tor Qoa Tot water Qye Qa Qoe KJfm Qya sp Qa msw Qm msw Qoe Qoa Tor Qoa Tor Tot Qoa Qm Tot Qoa Qoa Qoa msw Qya 10 10 22 40 52 25 46 85 40 60 70 80 70 40 80 66 68 57 45 52 24 10 60 32 60 10 20 32 24 60 76 53 43 55 50 54 25 45 30 35 30 45 33 20 21 40 36 44 48 50 45 56 45 40 52 45 50 75 46 24 15 42 26 16 44 36 34 24 31 47 34 36 35 32 29 44 47 39 35 54 27 30 30 35 26 46 24 38 45 58 70 30 27 7 25 10 15 20 15 19 18 75 21 15 12 11 14 20 20 25 6 16 30 20 32 35 35 43 30 30 26 30 70 30 20 16 65 77 35 30 20 14 35 20 5 38 32 30 32 20 30 10 20 15 10 5 26 20 10 10 15 20 20 25 32 54 27 60 15 35 35 WILMAR AVENUE FAULT OCEANO FAULT OCEANO FAULT 0 0 0 1 1 1 .5 .5 2 2 2 Thousand Feet Kilometers Miles Scale 1:24,000 Contour Interval 20 feet Supplementary Contour Interval 10 feet National Geodetic Vertical Datum of 1929 MN GN UTM GRID AND 2013 MAGNETIC NORTH DECLINATION AT CENTER OF SHEET 235 MILS 25 MILS 13°13’ 1°24’ STATE OF CALIFORNIA – EDMUND G. BROWN JR., GOVERNOR THE NATURAL RESOURCES AGENCY – JOHN LAIRD, SECRETARY FOR NATURAL RESOURCES DEPARTMENT OF CONSERVATION – MARK NECHODOM, CONSERVATION DIRECTOR CALIFORNIA GEOLOGICAL SURVEY JOHN G. PARRISH, Ph.D., STATE GEOLOGIST PRELIMINARY GEOLOGIC MAP OF THE OCEANO 7.5’ QUADRANGLE, CALIFORNIA Copyright © 2013 by the California Department of Conservation California Geological Survey. All rights reserved. No part of this publication may be reproduced without written consent of the California Geological Survey. "The Department of Conservation makes no warranties as to the suitability of this product for any given purpose." PRELIMINARY GEOLOGIC MAP OF THE OCEANO 7.5' QUADRANGLE SAN LUIS OBISPO COUNTY, CALIFORNIA: A DIGITAL DATABASE VERSION 1.0 By Peter J. Holland Digital Preparation by Peter J. Holland and Matt D. O’Neal 2013 This geologic map was funded in part by the USGS National Cooperative Geologic Mapping Program, Statemap Award no. G12AC20278 35°7'30'' 120°30' 35° 35° 120°30' 35°7'30'' Projection: Universal Transverse Mercator, Zone 10N, North American Datum 1927. Topographic base from U.S. Geological Survey Oceano 7.5-minute Quadrangle, 1979. Shaded relief image derived from USGS 1/3 arc-second National Elevation Dataset (NED). 120°38'30'' 120°38'30'' Professional Licenses and Certifications: P.J. Holland, PG No. 7994, CEG No. 2400 Preliminary Geologic Map available from: http://www.conservation.ca.gov/cgs/rghm/rgm/preliminary_geologic_maps.htm 120°37'30'' 120°37'30'' (Paso Robles) - Adjacent 30’ x 60’ quadrangles S anta M a rg ari t a L a k e L o pe z Lak e Twi t ch e ll R es e rv oi r Twi t c h ell Res Sa nt a Mar ia R iv e r 135 58 41 229 227 166 46 1 101 Santa Maria 5 Kilometers 5 Miles CAYUCOS MORRO BAY NORTH MORRO BAY SOUTH PORT SAN LUIS PISMO BEACH SAN LUIS OBISPO ARROYO GRANDE NE LOPEZ MTN TAR SPRING RIDGE CALDWELL MESA LOS MACHOS HILLS BRANCH MTN MIRANDA PINE MTN HUASNA PEAK NIPOMO OCEANO CHIMNEY CANYON SANTA MARGARITA SANTA MARGARITA LAKE WILSON CORNER CAMATTA RANCH POZO SUMMIT LA PANZA RANCH LA PANZA CALIFORNIA VALLEY LA PANZA NE ATASCADERO (P (P (P (Pas as s aso Robl les es) ) ) (Paso Robles) (Paso Robles) - Adjacent 30’ x 60’ quadrangles (T (T (T (T (T T aft) Taft) (S (S (S (S (S (S (S ( (S (S (S an an an an an anta t t ta t ta M M M Maria) (S (San anta M Maria) Mapping completed under STATEMAP PREVIOUS YEARS CURRENT YEAR FY 2008-09 FY 2010-11 FY 2009-10 FY 2011-12 FY 2012-13 FY 2012-13 121°0’0” 120°30’0” 120°0’0” 35°30’0” 35°0’0” MAP SYMBOLS Strike and dip of bedding plane. Horizontal Bedding Sand boil caused by 2003 M6.5 San Simeon earthquake Lateral spread extensional features caused by 2003 M6.5 San Simeon earthquake Lateral spread compressional features caused by 2003 M6.5 San Simeon earthquake 30 Synclinal axis - Solid where accurately located, dashed where approximately located, dotted where concealed. Arrow shows plunge direction. Anticlinal axis - Solid where accurately located, dashed where approximately located, dotted where concealed. Arrow shows plunge direction. Contact between map units - Solid where accurately located, dashed where approximately located, dotted where concealed. Fault - Solid where accurately located, dashed where approximately located, dotted where concealed. U = upthrown block; D = downthrown block. X California Department of Water Resources, 2002, Water Resources of the Arroyo Grande – Nipomo Mesa Area, Southern District Report. Dibblee, T.W. Jr., 2006, Geologic Map of the Oceano Quadrangle, San Luis Obispo County, California: Dibblee Geology Center Map #DF-209, Scale 1:24,000 Hall, C.A., 1973, Geology of the Arroyo Grande 15’ quadrangle, San Luis Obispo County, California: California Division of Mines and Geology Map Sheet 24, Scale 1:48,000 Holzer, T.L., Noce, T.E., Bennett, M.J., Di Alessandro, C., Boatwright, J., Tinsley, III, J.C., Sell, R.W., Rosenberg, L.I., 2004, Liquefaction-induced lateral spreading in Oceano, California, during the 2003 San Simeon Earthquake. USGS Open-File Report 2004-1269, 51 pp. Knott, J.R. and Eley, D.S., 2006, Early to Middle Holocene Coastal Dune and Estuarine Deposition, Santa Maria Valley, California, Physical Geography, 27, 2, pp. 127-136. Lettis, W.R. and Hall, N.T., 1994, Los Osos Fault Zone, San Luis Obispo County, California in Alterman, I.B., McMullen, R.B., Cluff, L.S., and Slemmons, D.B., editors, Seismotectonics of the Central California Coast Ranges: Geological Society of America Special Paper 292, p. 73-102. Nitchman, S.P., 1988, Tectonic geomorphology and neotectonics of the San Luis Range, San Luis Obispo County, California: University of Nevada, Reno, M.S. thesis, 120 pp. Hanson, K.L., Wesling, J.R., Lettis, W.R., Kelson, K.I., and Mezger, L., 1994, Correlation, Ages and Uplift Rates of Quaternary Marine Terraces: South-Central Coastal California in Alterman, I.B., McMullen, R.B., Cluff, L.S., and Slemmons, D.B., editors, Seismotectonics of the Central California Coast Ranges: Geological Society of America Special Paper 292, p. 45 - 72. REFERENCES SURFICIAL DEPOSITS Artificial fill (historic) - various amounts of fill along levees and highway and railroad embankments. Stream channel deposits (late Holocene) - Unconsolidated sand, gravel and cobbles in active channels. Alluvial flood-plain deposits (late Holocene) - Active and recently active flood-plain deposits. Consists of unconsolidated sandy, silty, and clay-bearing alluvium. Beach sand (late Holocene) – Unconsolidated beach deposits consisting mostly of fine- to medium-grained well-sorted sand. Dune sand (late Holocene) – Unconsolidated, well-sorted white to brown windblown sand. Forms active dunes behind modern beaches. Landslide deposits (Holocene to late Pleistocene) – Highly fragmented to largely coherent landslide deposits. Young eolian deposits (Holocene) – Vegetated stationary sand dune deposits displaying dune morphology. Well-sorted white to brown windblown sand. Inception of dune sheet occurred at approximately 3.5 to 4.3 ka (Knott and Eley, 2006). Young alluvial valley deposits, undivided (Holocene to late Pleistocene) – Unconsolidated sand, silt, and clay-bearing alluvium deposited on flood-plains and along valley floors. Surfaces are slightly dissected and display weak soil development. Approximately 4.3 to 11 ka in the Santa Maria Valley (Knott and Eley, 2006). Old eolian deposits (late Pleistocene) – well sorted red to brown wind blown sand with weak soil development in places. Surfaces are dissected and dune morphology is generally obscured. Older alluvium (late to middle Pleistocene) – Unconsolidated boulders, cobbles, gravel, sand, silt and clay poorly to moderately sorted; some discontinuous horizontal bedding, weakly to strongly cemented horizons (duripans) present locally, clasts generally consist of Franciscan Complex, Obispo and Monterey Formation lithologies. Marine deposits (middle to late Pleistocene) – Unconsolidated, well to moderately sorted cobbles and sand; clasts are typically subrounded to rounded and consist of Franciscan Complex, Obispo and Monterey Formation lithologies. (Hansen, et al, 1994). TERTIARY AND OLDER ROCKS Pismo Formation, Squire member (lower Pliocene) – Massive, white to light gray, fine- to medium-grained, quartzose to arkosic silty sandstone. Sand grains subrounded to subangular, 75-80% quartz, 15-20% feldspar, less than 15% mafic minerals (Hall, 1973). Monterey Formation (upper to middle Miocene) Cherty shale – Bedded, resistant chert, color varies from white and gray to brown and reddish-brown, weathering to chalky white. Brittle, conchoidal fracturing, commonly sheared, beds ½ to 6-inches thick, commonly laminated, locally interbedded with siltstone (Tms) and diatomite (Hall,1973). Siltstone – Brown to white siltstone with some claystone. Siltstone and dolomitic claystone – Tan to yellowish-white siltstone and dolomitic claystone locally tuffaceous or interbedded with chert. Obispo Formation (lower Miocene) – Coarse-grained tuff with subangular clasts of pumice (5%-50%), perlite (5%-15%), white to dark-gray glass shards (20%) and feldspar (5%) in a vitric ashy matrix; locally zeolitized or silicified (Tor) and commonly altered to montmorillonite (Hall, 1973). Zeolitized tuff – Resistant, hard, fine-grained, zeolitized or silicied tuff. Forms resistant outcrops. Rincon Shale (Oligocene to lower Miocene) – Dark brown siltstone that is exposed in a road cut along Highway 101. Franciscan Complex (Cretaceous to Jurassic) Mélange – Chaotic mixture of fragmented rock masses embedded in a penetratively sheared matrix. Matrix is not exposed in the Oceano Quadrangle. Resistant blocks are exposed only within the Los Berros Creek area and include: Greywacke Chert Greenstone Serpentinite Mélange and slope wash – Areas surrounding resistant blocks interpreted to be mélange matrix largely covered by slope wash. Qa Qhc af Qb Qd Qoa Qm Qya Qoe Qls Qye Tpsq Tr msw KJfm Tms Tmc Tmb Tor Tot gw ch mv sp DESCRIPTION OF MAP UNITS Qoe Qoa Qm Holocene Pleistocene Pliocene Miocene Oligocene QUATERNARY TERTIARY CRETACEOUS JURASSIC Tms Tor SURFICIAL DEPOSITS TERTIARY AND OLDER ROCKS CORRELATION OF MAP UNITS Qa Qhc Qb Qls Qya Qye Qd af KJfm gw sp ch mv Tpsq Tmc Tmb Tot Tr ? msw ? ? Revised: 08/26/2013
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W I L M A R A V E N U E F A U L T
O C E A N O FA U LT
OC
E A NO
FA U
LT
0
0
0
1
1
1.5
.5 2
2
2Thousand Feet
Kilometers
Miles
Scale 1:24,000
Contour Interval 20 feetSupplementary Contour Interval 10 feet
National Geodetic Vertical Datum of 1929
MN
GN
UTM GRID AND 2013 MAGNETIC NORTHDECLINATION AT CENTER OF SHEET
235 MILS
25 MILS
13°13’
1°24’
STATE OF CALIFORNIA – EDMUND G. BROWN JR., GOVERNORTHE NATURAL RESOURCES AGENCY – JOHN LAIRD, SECRETARY FOR NATURAL RESOURCES
DEPARTMENT OF CONSERVATION – MARK NECHODOM, CONSERVATION DIRECTOR CALIFORNIA GEOLOGICAL SURVEYJOHN G. PARRISH, Ph.D., STATE GEOLOGIST PRELIMINARY GEOLOGIC MAP OF THE OCEANO 7.5’ QUADRANGLE, CALIFORNIA
Copyright © 2013 by the California Department of ConservationCalifornia Geological Survey. All rights reserved. No part ofthis publication may be reproduced without written consent of theCalifornia Geological Survey.
"The Department of Conservation makes no warranties as to thesuitability of this product for any given purpose."
PRELIMINARY GEOLOGIC MAP OF THEOCEANO 7.5' QUADRANGLE
SAN LUIS OBISPO COUNTY, CALIFORNIA: A DIGITAL DATABASEVERSION 1.0
By Peter J. Holland
Digital Preparation by
Peter J. Holland and Matt D. O’Neal
2013
This geologic map was funded in part by the USGS National Cooperative Geologic MappingProgram, Statemap Award no. G12AC20278
35°7'30''120°30'
35°35°120°30'
35°7'30''
Projection: Universal Transverse Mercator, Zone 10N, North American Datum 1927.
Topographic base from U.S. Geological SurveyOceano 7.5-minute Quadrangle, 1979.Shaded relief image derived from USGS 1/3 arc-second National Elevation Dataset (NED).
120°38'30''
120°38'30''
Professional Licenses and Certifications: P.J. Holland, PG No. 7994, CEG No. 2400
Preliminary Geologic Map available from:http://www.conservation.ca.gov/cgs/rghm/rgm/preliminary_geologic_maps.htm
120°37'30''
120°37'30''
(Paso Robles) - Adjacent 30’ x 60’ quadrangles
Santa Margarita Lake
Lopez Lake
Twitchell Reservoir
Twitchell Res
Santa Maria River135
58
41229
227
166
46
1
101
SantaMaria5
Kilometers5
Miles
CAYUCOS
MORROBAYNORTH
MORROBAYSOUTH
PORTSAN LUIS
PISMOBEACH
SAN LUISOBISPO
ARROYOGRANDE NE
LOPEZMTN
TARSPRINGRIDGE
CALDWELLMESA
LOSMACHOSHILLS
BRANCHMTN
MIRANDAPINEMTN
HUASNAPEAK
NIPOMO
OCEANO
CHIMNEYCANYON
SANTAMARGARITA
SANTAMARGARITALAKE
WILSONCORNER
CAMATTARANCH
POZOSUMMIT
LA PANZARANCH
LA PANZA
CALIFORNIAVALLEY
LA PANZANE
ATASCADERO
(P(P(P(Pasassaso Roblleses)))(Paso Robles)
(Paso Robles) - Adjacent 30’ x 60’ quadrangles
(T(T(T(T(TTaft)Taft)
(S(S(S(S(S(S(S((S(S(S( anananananantatttatta MMMMaria)(S(Sananta MMaria) Mapping completed under STATEMAP
PREVIOUS YEARS
CURRENT YEAR
FY 2008-09
FY 2010-11
FY 2009-10
FY 2011-12
FY 2012-13
FY 2012-13
121°0’0” 120°30’0” 120°0’0”
35°3
0’0”
35°0
’0”
MAP SYMBOLS
Strike and dip of bedding plane.
Horizontal Bedding
Sand boil caused by 2003 M6.5 San Simeon earthquake
Lateral spread extensional features caused by 2003 M6.5 San Simeon earthquake
Lateral spread compressional features caused by 2003 M6.5 San Simeon earthquake
30
Synclinal axis - Solid where accurately located, dashed where approximately located, dotted where concealed. Arrow shows plunge direction. Anticlinal axis - Solid where accurately located, dashed where approximately located, dotted where concealed. Arrow shows plunge direction.
Contact between map units - Solid where accurately located, dashed where approximately located, dotted where concealed.
Fault - Solid where accurately located, dashed where approximately located, dotted where concealed. U = upthrown block; D = downthrown block.
X
California Department of Water Resources, 2002, Water Resources of the Arroyo Grande – Nipomo Mesa Area, Southern District Report.
Dibblee, T.W. Jr., 2006, Geologic Map of the Oceano Quadrangle, San Luis Obispo County, California: Dibblee Geology Center Map #DF-209, Scale 1:24,000
Hall, C.A., 1973, Geology of the Arroyo Grande 15’ quadrangle, San Luis Obispo County, California: California Division of Mines and Geology Map Sheet 24, Scale 1:48,000
Holzer, T.L., Noce, T.E., Bennett, M.J., Di Alessandro, C., Boatwright, J., Tinsley, III, J.C., Sell, R.W., Rosenberg, L.I., 2004, Liquefaction-induced lateral spreading in Oceano, California, during the 2003 San Simeon Earthquake. USGS Open-File Report 2004-1269, 51 pp.
Knott, J.R. and Eley, D.S., 2006, Early to Middle Holocene Coastal Dune and Estuarine Deposition, Santa Maria Valley, California, Physical Geography, 27, 2, pp. 127-136.
Lettis, W.R. and Hall, N.T., 1994, Los Osos Fault Zone, San Luis Obispo County, California in Alterman, I.B., McMullen, R.B., Cluff, L.S., and Slemmons, D.B., editors, Seismotectonics of the Central California Coast Ranges: Geological Society of America Special Paper 292, p. 73-102.
Nitchman, S.P., 1988, Tectonic geomorphology and neotectonics of the San Luis Range, San Luis Obispo County, California: University of Nevada, Reno, M.S. thesis, 120 pp.
Hanson, K.L., Wesling, J.R., Lettis, W.R., Kelson, K.I., and Mezger, L., 1994, Correlation, Ages and Uplift Rates of Quaternary Marine Terraces: South-Central Coastal California in Alterman, I.B., McMullen, R.B., Cluff, L.S., and Slemmons, D.B., editors, Seismotectonics of the Central California Coast Ranges: Geological Society of America Special Paper 292, p. 45 - 72.
REFERENCES
SURFICIAL DEPOSITS
Artificial fill (historic) - various amounts of fill along levees and highway and railroad embankments.
Stream channel deposits (late Holocene) - Unconsolidated sand, gravel and cobbles in active channels.
Alluvial flood-plain deposits (late Holocene) - Active and recently active flood-plain deposits. Consists of unconsolidated sandy, silty, and clay-bearing alluvium.
Beach sand (late Holocene) – Unconsolidated beach deposits consisting mostly of fine- to medium-grained well-sorted sand.
Dune sand (late Holocene) – Unconsolidated, well-sorted white to brown windblown sand. Forms active dunes behind modern beaches.
Landslide deposits (Holocene to late Pleistocene) – Highly fragmented to largely coherent landslide deposits.
Young eolian deposits (Holocene) – Vegetated stationary sand dune deposits displaying dune morphology. Well-sorted white to brown windblown sand. Inception of dune sheet occurred at approximately 3.5 to 4.3 ka (Knott and Eley, 2006).
Young alluvial valley deposits, undivided (Holocene to late Pleistocene) – Unconsolidated sand, silt, and clay-bearing alluvium deposited on flood-plains and along valley floors. Surfaces are slightly dissected and display weak soil development. Approximately 4.3 to 11 ka in the Santa Maria Valley (Knott and Eley, 2006).
Old eolian deposits (late Pleistocene) – well sorted red to brown wind blown sand with weak soil development in places. Surfaces are dissected and dune morphology is generally obscured.
Older alluvium (late to middle Pleistocene) – Unconsolidated boulders, cobbles, gravel, sand, silt and clay poorly to moderately sorted; some discontinuous horizontal bedding, weakly to strongly cemented horizons (duripans) present locally, clasts generally consist of Franciscan Complex, Obispo and Monterey Formation lithologies.
Marine deposits (middle to late Pleistocene) – Unconsolidated, well to moderately sorted cobbles and sand; clasts are typically subrounded to rounded and consist of Franciscan Complex, Obispo and Monterey Formation lithologies. (Hansen, et al, 1994).
TERTIARY AND OLDER ROCKS
Pismo Formation, Squire member (lower Pliocene) – Massive, white to light gray, fine- to medium-grained, quartzose to arkosic silty sandstone. Sand grains subrounded to subangular, 75-80% quartz, 15-20% feldspar, less than 15% mafic minerals (Hall, 1973).
Monterey Formation (upper to middle Miocene)
Cherty shale – Bedded, resistant chert, color varies from white and gray to brown and reddish-brown, weathering to chalky white. Brittle, conchoidal fracturing, commonly sheared, beds ½ to 6-inches thick, commonly laminated, locally interbedded with siltstone (Tms) and diatomite (Hall,1973).
Siltstone – Brown to white siltstone with some claystone.
Siltstone and dolomitic claystone – Tan to yellowish-white siltstone and dolomitic claystone locally tuffaceous or interbedded with chert.
Obispo Formation (lower Miocene) – Coarse-grained tuff with subangular clasts of pumice (5%-50%), perlite (5%-15%), white to dark-gray glass shards (20%) and feldspar (5%) in a vitric ashy matrix; locally zeolitized or silicified (Tor) and commonly altered to montmorillonite (Hall, 1973).
Zeolitized tuff – Resistant, hard, fine-grained, zeolitized or silicied tuff. Forms resistant outcrops.
Rincon Shale (Oligocene to lower Miocene) – Dark brown siltstone that is exposed in a road cut along Highway 101.
Franciscan Complex (Cretaceous to Jurassic)
Mélange – Chaotic mixture of fragmented rock masses embedded in a penetratively sheared matrix. Matrix is not exposed in the Oceano Quadrangle. Resistant blocks are exposed only within the Los Berros Creek area and include:
Greywacke
Chert
Greenstone
Serpentinite
Mélange and slope wash – Areas surrounding resistant blocks interpreted to be mélange matrix largely covered by slope wash.
Qa
Qhc
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Qb
Qd
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Qm
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Qoe
Qls
Qye
Tpsq
Tr
msw
KJfm
Tms
Tmc
Tmb
Tor
Tot
gw
ch
mv
sp
DESCRIPTION OF MAP UNITS
QoeQoa
Qm
Holocene
Pleistocene
Pliocene
Miocene
Oligocene
QUATERNARY
TERTIARY
CRETACEOUS
JURASSIC
Tms
Tor
SURFICIAL DEPOSITS
TERTIARY AND OLDER ROCKS
CORRELATION OF MAP UNITS
QaQhc Qb
QlsQyaQye
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KJfm
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Revised: 08/26/2013
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