GEOLOGIC MAP OF THE OXNARD 7.5\' QUADRANGLE VENTURA COUNTY, CALIFORNIA: A DIGITAL DATABASE

Preliminary Geologic Map available from: http://www.conservation.ca.gov/cgs/rghm/rgm/preliminary_geologic_maps.htm

STATE OF CALIFORNIA- GRAY DAVIS, GOVERNOR THE RESOURCES AGENCY- MARY NICHOLS, SECRETARY FOR RESOURCES DEPARTMENT OF CONSERVATION- DARRYL YOUNG, DIRECTOR

CALIFORNIA GEOLOGICAL SURVEY JAMES F. DAVIS, STATE GEOLOGIST

119°15'

34°15'

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Qht

Qw

Qhf

Qht Qha

Qht

VERSION 1.0 By Kevin B. Clahan

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Qw

Qht Qht

Qha Qha Qht

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Qha2

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Qh t

Digital Database by: Marina T. Mascorro

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af Qht

Qht

Qht

af Qw

Qht

2003

Qha2 Qht

af

Qw Qht

Qht

af

Qb

Qht

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Qha Qha

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Qe

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EXPLANATION OF MAP UNITS

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af

GEOLOGIC MAP OF THE OXNARD 7.5' QUADRANGLE VENTURA COUNTY, CALIFORNIA: A DIGITAL DATABASE

119°07'30'' 119°07'30'' 34°15'

CORRELATION OF MAP UNITS

th Qha Qha

Qhw3

af

Artificial fill; may be engineered and/or non-engineered.

alf

Artificial levee fill; may be engineered and/or non-engineered.

af

alf

Qw

Qht

Qha

Qhw3

Qht 3

Qha 3

Qb

Qe

Qes

Qha Qha Qha3 Qe s

Qha1

Qw

Active wash deposits within major river channels; composed of unconsolidated silt, sand and gravel.

Qe Qht3

Qe

Qhf Qhw2

Qb

Active beach deposits; composed mainly of loose sand, well-sorted, fine-to coarse-grained.

Qe

Active coastal eolian (sand dune) deposits, consist of loose sand and silt.

Qhw1

Qha 2 Qht 1

Qha1

Qhff

}} } Holocene

Quaternary

Cenozoic

Qhff

Qe

MAP SYMBOLS

Qha2

Qes

Qha1

Qb

Active coastal estuarine deposits; composed of submerged/saturated silty clay. Contact between map units of different relative age; generally approximately located.

Qht3 Qe

Qha2

O x na

nc line y S d r

Qha1

Qhw2

Qht Qht

Latest Holocene stream terrace deposits, deposited in point bar and overbank settings associated with unit Qw; composed of unconsolidated, poorly sorted, clayey sand and sandy clay with gravel.

Qha

Latest Holocene alluvial deposits, deposited as overbank material associated with unit Qw, recognized by scour and incised channeling features; composed of unconsolidated, poorly sorted, clayey sand with some gravel. May include terrace deposits (Qht).

Contact between terraced alluvial units; hachures point towards topographically lower surface.

Contact between similar map units; generally approximately located.

Qha2 Qht3

Qhw3 Holocene wash deposit; composed of unconsolidated sand, silt and gravel.

Qhff

Qht 3

Holocene stream terrace deposits, deposited in point bar and overbank settings associated with unit Qhw3; composed of unconsolidated clayey sand and sandy clay with gravel.

Qha 3

Holocene alluvial deposits, deposited as overbank material associated with unit Qhw3, recognized by scour and incised channeling features; composed of unconsolidated, poorly sorted, clayey sand with some gravel.

Qhw2

Holocene wash deposit; composed of unconsolidated sand, silt and gravel.

Qha2 Qhw3

Qhw1

Qhff

Qha3

Qha 2 Holocene alluvial deposits, deposited as overbank material associated with unit Qhw2 ,

recognized by scour and incised channeling features; composed of unconsolidated, poorly sorted, clayey sand with some gravel.

Qha2

Fault; dotted where concealed.

Axis of anticline; dotted where concealed.

Axis of syncline; dotted where concealed.

REFERENCES California Division of Mines and Geology, 1975, Seismic hazards study of Ventura County, California: California Department of Conservation, Division of Mines and Geology Open-File Report 76-5, 396 p., 9 plates.

Qht3

Qhw1 Qha3

Holocene wash deposit; composed of unconsolidated sand, silt and gravel.

Edwards, R.D., Rabey, D.F. and Kover, R.W., 1970, Soil survey of the Ventura area, California: U.S. Department of Agriculture, Soil Conservation Services, 151 p., scale 1:24,000.

Qha3

Qht 1 Qha1

Qha1

Qha2

Qht3

Qh t3

Holocene stream terrace deposits, deposited in point bar and overbank settings associated with unit Qhw1 ; composed of unconsolidated clayey sand and sandy clay with gravel. Holocene alluvial deposits, deposited as overbank material associated with unit Qhw1, recognized by scour and incised channeling features; composed of unconsolidated, sandy clay with some gravel.

Qhw1

Qhf

Qha3

Qb

Qhff

Holocene alluvial fan deposits, includes active fan deposits, deposited by streams emanating from mountain canyons to the north onto the alluvial valley floor; deposits originate as debris flows, hyperconcentrated mudflows or braided stream flows; composed of moderately to poorly sorted and moderately to poorly bedded sandy clay with some silt and gravel. Holocene alluvial fan deposits, fine facies; fine-grained alluvial fan and flood plain overbank deposits on very gently sloping portions fo the valley floor; composed of predominantly clay with interbedded lenses of coarser alluvium (sand and occasional gravel).

Qht3

Qha3 af

Qht1

Huftile, G.J. and Yeats, R.S., 1995, Convergence rates across a displacement transfer zone in the western Transverse Ranges, Ventura Basin, California: Journal of Geophysical Research, v. 88, No. B2, p. 2043-2067. HItchcock, C.S., Helms, J.D., Randolph, C.E., Lindvall, S.C., Weaver, K.D., and Lettis, W.R., 2000, Liquefaction hazard mapping, Ventura County, California: Final Technical Report, U.S. Geological Survey, Award 99-HQ-GR-0117, 21 p, 4 plates. Loyd, R.C., 2002, Liquefaction zones in the Oxnard 7.5-minute quadrangle, Ventura County, California: California Geological Survey, Seismic Hazard Zone Report 052, Section 1, 13 p. McCoy, G. and Sarna-Wojcicki, A.M., 1978, Preliminary map showing surficial materials of the Ventura-Oxnard plain area, California: U.S. Geological Survey Open-File Report 78-1065, scale 1:125,000. Namson, J.S., 1987, Structural transect through the Ventura Basin and Western Transverse Ranges: Society of Economic Mineralogists and Paleontologists, Pacific Section Guidebook 48A, p. 29-41. Sarna-Wojcicki, A.M., Williams, K.M. and Yerkes, R.F., 1976, Geology of the Ventura fault, Ventura County, California: U.S. Geological Survey Miscellaneous Field Studies, Map MF-781, 3 sheets, scale 1:6,000.

Qhw3 af

Qhff Qe

Tinsley, J.C., Youd, T.L., Perkins, D.M. and Chen, A.T.F., 1985, Evaluating liquefaction potential in Ziony, J.I., editor, Evaluating earthquake hazards in the Los Angeles Region, an earth-science perspective: U.S. Geological Survey Professional Paper 1360, pp. 263-315.

Qb

Weber, F.H., Jr., Cleveland, G.B., Kahle, J.E., Kiessling, E.W., Miller, R.V., Mills, M.F., Morton, D.M., and Cilweck, B.A., 1973, Geology and mineral resources study of southern Ventura County, California: California Division of Mines and Geology, Preliminary Report 14, 102 p., scale 1:48,000.

101

a ur nt Ve

s ta Pi oint P

Qha3

33

Ventura

126

Saticoy

El Rio

Qhff

rd na Ox

Camarillo Oxnard

1

Point Hueneme

Yeats, R.S., Huftile, G.J. and Grigsby, F.B., 1988, Oak Ridge fault, Ventura fold belt, and the Sisar decollement, Ventura Basin, California: Geology, v. 16, p. 1112-1116.

t in Po u ug

M

Qb

Yeats, R.S., 1983, Large-scale Quaternary detachments in Ventura Basin, Southern California: Journal of Geophysical Research, v. 88, no. B1, p. 569-583.

Qha

Qht1

Qha

Yeats, R.S., 1988, Late Quaternary slip rate on the Oak Ridge fault, Transverse Ranges, California: Implications for seismic risk: Journal of Geophysical Research, v. 93, No. B10, pp. 12,137-12,149. Yeats, R.F., 1989, Oak Ridge fault, Ventura Basin, California: Slip rates and late Quaternary history: U.S. Geological Survey Open-File Report 89-343, 30 p.

Qe

Yeats, R.F. and Rockwell, T.K., 1991, Quaternary geology of the Ventura and Los Angeles basins, California: in Morrison, R.B., editor, Quaternary nonglacial geology: Conterminous U.S.: Geological Society of America, DNAG v. K-2, p.185-189.

Qhff

Yerkes, R.F., Sarna-Wojcicki, A.M., and Lajoie, K.R., 1987, Geology and Quaternary deformation of the Ventura area: U.S. Geological Survey Professional Paper 1339, p. 169-178, Plate 11.1, scale 1:24,000. Ziony, J.I. and Yerkes, R.F., 1985, Evaluating earthquake and surface faulting potential in Ziony, J.I., editor, Evaluating earthquake hazards in the Los Angeles Region, an earthscience perspective: U.S. Geological Survey Professional Paper 1360, p. 43-91.

alf Qe s

34°07'30'' 119°15'

Topographic base from the U.S. Geological Survey UTM Projection

34°07'30'' 119°07'30''

0 GN

1°14' 22 MILS

.5

1

2

MN

15½° 276 MILS

Miles 0

.5

1

2 Kilometers

0

1

2

3

Ziony, J.I. and Jones, L.M., 1989, Map showing late Quaternary faults and 1978-84 seismicity of the Los Angeles region, California: U.S. Geological Survey Miscellaneous Field Studies Map MF-1964, scale 1:250,000.

This geologic map was funded in part by the USGS National Cooperative Geologic Mapping Program, Statemap Award no. 02HQAG0018 Copyright © 2003 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.

Thousand Feet UTM GRID AND 1967 MAGNETIC NORTH DECLINATION AT CENTER OF SHEET

Contour Interval 5 Feet

"The Department of Conservation makes no warranties as to the suitability of this product for any given purpose."