Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. 

Government

This map was printed on an electronic plotter directly from digital files. 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.

For sale by U.S. Geological Survey, Information Services, Box 25286, Federal Center, Denver, CO 80225, 1–888–ASK–USGS

Digital files available at https://doi.org/10.3133/ofr20181023

Suggested Citation: Hartwell, S.R., Johnson, S.Y., and Davenport, C.W., 2018, Offshore and onshore geology and geomorphology, 

Offshore of Gaviota map area, California, sheet 9 in Johnson, S.Y., Dartnell, P., Cochrane, G.R., Hartwell, S.R., Golden, N.E., Kvitek, R.G., 

and Davenport, C.W. (S.Y. Johnson and S.A. Cochran, eds.), California State Waters Map Series—Offshore of Gaviota, California: U.S. 

Geological Survey Open-File Report 2018–1023, pamphlet 41 p., 9 sheets, scale 1:24,000, https://doi.org/10.3133/ofr20181023.

ISSN 2331-1258 (online)

https://doi.org/10.3133/ofr20181023

REFERENCES CITED

Christie-Blick, N., and Biddle, K.T., 1985, Deformation and basin formation along strike-slip faults, in Biddle, K.T., and 

Christie-Blick, N., eds., Strike-slip deformation, basin formation, and sedimentation: Society of Economic 

Paleontologists and Mineralogists Special Publication 37, p. 1–34.

Dibblee, T.W., Jr., 1988a, Geologic map of the Santa Rosa Hills and Sacate quadrangles, Santa Barbara County, California 

(H.E. Ehrenspeck, ed. [1988]): Dibblee Geological Foundation Map DF-17, scale 1:24,000.

Dibblee, T.W., Jr., 1988b, Geologic map of the Solvang and Gaviota quadrangles, Santa Barbara County, California (H.E. 

Ehrenspeck, ed. [1988]): Dibblee Geological Foundation Map DF-16, scale 1:24,000.

Draut, A.E., Hart, P.E., Lorenson, T.D., Ryan, H.F., Wong, F.L., Sliter, R.W., and Conrad, J.E., 2009, Late Pleistocene to 

Holocene sedimentation and hydrocarbon seeps on the continental shelf of a steep, tectonically active margin, southern 

California, USA: Marine Geophysical Research, p. 193–206, available at https://doi.org/10.1007/s11001-009-9076-y.

Eichhubl, P., Greene, H.G., and Maher, N., 2002, Physiography of an active transpressive margin basin—High-resolution 

bathymetry of the Santa Barbara basin, southern California continental borderland: Marine Geology, v. 184, p. 95–120.

Fischer, P.J., 1998, Structure and tectonics of northwestern Santa Barbara basin, in Kunitomi, D.S., Hopps, T.E., and 

Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of 

Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, p, 79–96.

Fischer, P.J., and Cherven, B.B., 1998, The Conception Fan, Santa Barbara Basin, California, in Kunitomi, D.S., Hopps, T.E., 

and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of 

Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, p, 155–181.

Golden, N.E., and Cochrane, G.R., 2013, California Seafloor Mapping Program video and photograph portal: U.S. Geological 

Survey, Coastal and Marine Geology Program data portal, available at https://doi.org/10.5066/F7J1015K.

Keller, E.A., Duffy, M., Kennett, J.P., and Hill, T., 2007, Tectonic geomorphology and hydrocarbon-induced topography of the 

mid-Channel anticline, Santa Barbara basin, California: Geomorphology, v. 89, p. 274–286.

Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., 1998, Structure and petroleum geology, Santa Barbara Channel, 

California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous 

Publication 46, 328 p.

Lorenson, T.L., Wong, F.L., Dartnell, P., and Sliter, R.W., 2014, Greenhouse gases generated from the anaerobic 

biodegradation of natural offshore asphalt seepages in southern California: Geo-Marine Letters, v. 34, p. 281–295, 

available at https://doi.org/10.1007/s00367-014-0359-1.

Mann, P., 2007, Global catalogue, classification, and tectonic origin of restraining and releasing bends on active and ancient 

strike-slip fault systems, in Cunningham, W.D., and Mann, P., eds., Tectonics of strike-slip restraining and releasing 

bends: London, Geological Society of London, Special Publication 290, p. 13–142.

National Geodetic Survey, 2016, NOAA Shoreline Data Explorer: National Oceanic and Atmospheric Administration, 

National Geodetic Survey data viewer and database, accessed May 1, 2016, at http://www.ngs.noaa.gov/NSDE/.

Redin, T., Forman, J., Kamerling, M., and Galloway, J., 2005, Santa Barbara Channel structure and correlation 

sections—CS-32 to CS-42: American Association of Petroleum Geologists, Pacific Section, Publication CS 36, 12 

sheets.

Reid, J.A., Reid, J.M., Jenkins, C.J., Zimmerman, M., Williams, S.J., and Field, M.E., 2006, usSEABED—Pacific Coast 

(California, Oregon, Washington) offshore surficial-sediment data release: U.S. Geological Survey Data Series 182, 

available at http://pubs.usgs.gov/ds/2006/182/.

Sorlien, C.C., and Nicholson, C., 2015, Post 1-Ma deformation history of the Pitas Point-North Channel-Red Mountain fault 

system and associated folds in Santa Barbara channel, California: U.S. Geological Survey National Earthquake Hazards 

Reduction Program final report, Award G14AP00012, 24 p., available at https://earthquake.usgs.gov/cfusion/

external_grants/reports/G14AP00012.pdf.

Steel, E., Simms, A., Warrick, J., and Yokoyama, Y., 2015, Depositional history and stratigraphic architecture of lofted 

hyperpycnal flows in the Santa Barbara Channel, southern California [abs.]: American Association of Petroleum 

Geologists, Pacific Section, Convention, Oxnard, Calif., May 3–6, 2015, available at 

http://www.searchanddiscovery.com/abstracts/html/2015/90215pacsec/abstracts/S02.0.03.html. 

Warrick, J.A., Simms, A.R., Ritchie, A., Steel, E., Dartnell, P., Conrad, J., and Finlayson, D.P., 2013, Hyperpycnal 

plume-derived fans in the Santa Barbara Channel, California: Geophysical Research Letters, v. 40, p. 2,081–2,086.

Yerkes, R.F., Wagner, H.C., and Yenne, K.A., 1969, Petroleum development in the region of the Santa Barbara Channel: U.S. 

Geological Survey Professional Paper 679–B, p. 11–21.

EXPLANATION OF MAP SYMBOLS

Contact—Solid where location is certain or well located, dashed where location is approximate or inferred

Fault—Solid where location is certain, dashed where location is inferred, dotted where location is concealed, 

queried where uncertain 

Folds—Solid where location is certain, dashed where location is inferred, dotted where location is concealed

Anticline

Syncline 

Approximate modern shoreline—From National Oceanic and Atmospheric Administration’s Shoreline Data 

Explorer (National Geodetic Survey, 2016)

3-nautical-mile limit of California’s State Waters

Area of “no data”—Areas beyond 3-nautical-mile limit of California’s State Waters were not mapped as part of 

California Seafloor Mapping Program

DISCUSSION

Marine geology and geomorphology were mapped in the Offshore of Gaviota map area from the shoreline to the 

3-nautical-mile limit of California’s State Waters. The location of the shoreline, which is from the National Oceanic and 

Atmospheric Administration’s (NOAA’s) Shoreline Data Explorer, is based on their analysis of lidar imagery (National 

Geodetic Survey, 2016). Offshore geologic units were delineated on the basis of integrated analyses of adjacent onshore 

geology with multibeam bathymetry and backscatter imagery (sheets 1, 2, 3), seafloor-sediment and rock samples (Reid and 

others, 2006), digital camera and video imagery (Golden and Cochrane, 2013), and high-resolution seismic-reflection profiles 

(sheet 7). Bathymetric lidar and aerial photographs taken in multiple years were used to map the nearshore area (0 to 10 m 

water depth) and to link the offshore and onshore geology. 

The onshore geology was compiled from Dibblee (1988a,b); unit ages, which are derived from these sources, reflect 

local stratigraphic relations. In addition, some Quaternary units were modified by C.W. Davenport on the basis of analysis of 

2004 ifSAR and 2009 lidar imagery. 

The offshore part of the map area largely consists of a narrow (4- to 5-km-wide), gently (about 1° to 1.5°) offshoredipping shelf underlain by Neogene bedrock, as well as Holocene sediments that are derived primarily from Cañada de la 

Gaviota and smaller coastal watersheds that drain the Santa Ynez Mountains (see fig. 1–2, in pamphlet). Holocene nearshore 

and shelf deposits are primarily sand (unit Qms). Coarser grained sediments (unit Qmsc) are found mainly along the Gaviota 

sediment bar, a prominent bathymetric feature that extends southwestward for about 9 km from the mouth of Cañada de la 

Gaviota to the shelf break. The Gaviota sediment bar, which faces southeast, is as wide as 2 km and has a relatively flat (about 

1.4°) top that extends to water depths of 60 m. The steep (as much as 5°) bar front, which formed by advancing clinoforms 

(see fig. 5 on sheet 7), is bounded by an apron of coalescing, hummocky debris-flow lobes (unit Qda). Coarser grained 

sediment also is present in the eastern part of a small scour depression (unit Qmsd) found along the west edge of the map 

area, at a water depth of about 35 m. Sandy seafloor (unit aft) that is crossed by very low relief (about 10 to 20 cm high), 

widely spaced (about 5 to 15 m apart), northeast-trending ridges is found in two areas (827,209 and 289,593 m2

) about 3.5 km 

south of the Gaviota shoreline, in water depths of about 40 to 55 m; the morphology of these ridges suggests that they were 

formed by fishing trawls. 

Two subtle sediment lobes (unit Qmscl) are mapped near the east edge of the map area on the basis of their high 

backscatter and positive seafloor relief. These lobes, which occupy 257,490 and 92,932 m2, are found about 1,080 to 2,100 m 

offshore, in water depths of 35 to 55 m. The lobes are located offshore of the mouths of steep coastal watersheds, and they 

have been interpreted as the deposits of debris flows or hyperpycnal flows, or a combination of these processes (Warrick and 

others, 2013; Steel and others, 2015). Preliminary ages (Steel and others, 2015) on similar features to the east indicate that 

they may have formed as early as 8,500 years ago when sea level was significantly lower (Steel and others, 2015).

Finer grained sediment—the very fine sand, silt, and clay of unit Qmsf—is mapped primarily in the eastern part of the 

map area, between depths of about 60 m and the shelf break. The boundary between units Qms and Qmsf is based on 

observations and extrapolation from sparse sediment sampling (for example, Reid and others, 2006) and camera ground-truth 

surveying (Golden and Cochrane, 2013). Thus, the boundary between units Qms and Qmsf should be considered transitional 

and approximate and is expected to shift as a result of seasonal- to annual- to decadal-scale cycles in wave climate, sediment 

supply, and sediment transport. 

Fine-grained deposits similar to unit Qmsf also are found below the shelf break on the upper slope, at water depths 

greater than 90 m, where they are mapped as a separate unit (unit Qmsl) on the basis of their location and geomorphology. 

Both the shelf break and the distal part of the Gaviota sediment bar are incised by narrow rills and three large (150- to 

300-m-wide) channels (collectively mapped as unit Qmcr) that have been referred to either as “the Gaviota Canyons” 

(Fischer and Cherven, 1998) or as “Drake Canyon,” “Sacate Canyon,” and “Alegria Canyon” (Eichhubl and others, 2002). 

East of the south strand of the Santa Ynez Fault, bedrock exposures along the shoreline and on the inner shelf consist of 

siliceous and calcareous mudstone and shale of the Miocene Monterey Formation (unit Tm). West of this fault strand, bedrock 

outcrops in the nearshore and on the shelf consist primarily of marine shale, claystone, and diatomite of the upper Miocene 

and lower Pliocene Sisquoc Formation (unit Tsq). Seafloor outcrops of units Tm and Tsq both commonly have a “ribbed” 

appearance, reflecting the differential erosion of variably resistant interbeds. Because of the lack of sampling and their relative 

lack of distinctive seafloor morphology, some seafloor bedrock outcrops on the outer shelf cannot be confidently assigned to 

either unit Tm or unit Tsq; these areas are mapped as the undivided Tertiary bedrock unit (Tbu).

The Santa Barbara Channel region is a mature hydrocarbon province that has a long history of petroleum exploration and 

production (Kunitomi and others, 1998). The Offshore of Gaviota map area includes the western part of the Molino offshore 

gas field, as well as the Gaviota and Caliente offshore gas fields and the Alegria and Cuarta offshore oil fields (Yerkes and 

others, 1969). Seafloor geomorphic features associated with petroleum seepage include fields of dense pockmarks (unit 

Qmp), asphalt mounds (unit Qas), carbonate mats, and mud volcanoes (see, for example, Keller and others, 2007). The 

pockmarks in the map area are predominantly grouped or, less commonly, solitary; are circular to elliptical; range in size from 

50 to 150 m along their long axis; typically are 20 to 40 cm deep; and commonly have a central cone as much as 150 cm high. 

The largest field of pockmarks (709,384 m2

) is along the trace of the south strand of the Santa Ynez Fault, along which 

fractured bedrock may provide a conduit for seepage. Asphalt mounds in the map area are found along and near the crest of 

the Molino Anticline where they generally are less than 4 m high and less than 40 m in diameter (Lorenson and others, 2014); 

Draut and others (2009) noted that such mounds likely consist of a mixture of tar and sediment. Lorenson and others (2014) 

calculated a composite volume of asphalt in the Gaviota area of 4.5×105 m3. Offshore pipelines, which are associated with 

offshore oil and gas development, are mapped as unit af. 

Neogene strata are deformed in a fold belt that, on a regional scale, is located within a large, east-west-striking, southdipping homocline that extends from the south flank of the Santa Ynez Mountains into the offshore. Nearby regional cross 

sections (Redin and others, 2005) and industry seismic-reflection profiles (see fig. 6 on sheet 7; see also, Sorlien and 

Nicholson, 2015) showed that the homocline formed above the blind Pitas Point–North Channel Fault system, which in the 

offshore extends westward for more than 100 km, from Pitas Point (10 km northwest of Ventura) to beyond Gaviota and Point 

Conception (see fig. 1–3, in pamphlet). South of Gaviota, the tip of the Pitas Point–North Channel Fault is inferred to be 

buried beneath the slope, about 10 km offshore, to a depth of about 2 to 3 km below sea level. 

The southwest-striking south strand of the Santa Ynez Fault, as mapped onshore by Dibblee (1988b), is unique among 

Santa Barbara fold-belt structures in that it obliquely crosses the Santa Ynez Mountains and the dominant east-west-trending 

structural grain. In the offshore, the fault was difficult to map, despite our dense coverage of seismic-reflection data (see sheet 

7), because (1) the pre-LGM section on the shelf includes massive, reflection-free zones, probably caused by either interstitial 

gas or steeply dipping strata, and (2) the adjacent slope is mainly underlain by the massive to chaotic seismic facies of the 

Conception fan. The location of the fault on our map coincides with the northwestern margin of the Gaviota sediment bar on 

the midshelf to outer shelf (see fig. 1–2, in pamphlet; see also, sheets 1, 2), suggesting that faulting may have been a control 

on bar development. In contrast to previously published offshore mapping of Fischer (1998), we map the Santa Ynez Fault as 

having a straighter strike (at about 224° azimuth) and being located as much as 900 m farther northwest on the midshelf to 

outer shelf. Both Fischer (1998) and Eichhubl and others (2002) inferred that the Santa Ynez Fault “captured” the heads of 

“Drake Canyon” and “Sacate Canyon” at the shelf break; indeed, the linearity of these canyon heads is striking, and it 

suggests left-lateral slip. Accordingly, our map shows a secondary, discontinuous strand of the fault that extends through these 

canyon heads; however, we cannot trace these strands to the northeast across the shelf using seismic-reflection profiles, and so 

their presence is based solely on bathymetry. South of the map area, the south strand of the Santa Ynez Fault appears to 

disperse into a diffuse zone of several shorter, more east-west-striking contractional faults on the outer shelf, and it cannot be 

traced across the slope into deeper water. This fanlike pattern of faults is characteristic of terminating strike-slip faults 

(Christie-Blick and Biddle, 1985; Mann, 2007). 

In the offshore part of the map area, closely spaced seismic-reflection profiles (see sheet 7) image many shallow, 

west-northwest-striking folds that have variable geometries, lengths, amplitudes, degrees of continuity, and wavelengths. The 

two longest folds, the 17-km-long Molino Anticline and the 22-km-long Government Point Syncline, are truncated to the west 

and east, respectively, by the south strand of the Santa Ynez Fault. These regionally extensive folds, as well as many other 

shorter, east-west-striking structures, are probably rooted in blind thrust faults and back-thrust faults in the hanging wall 

above the Pitas Point–North Channel Fault system.

LIST OF MAP UNITS

[See Description of Map Units (chapter 7, in pamphlet) for complete map-unit descriptions]

OFFSHORE GEOLOGIC AND GEOMORPHIC UNITS

[Note that composite units (gray- and white-stippled areas) are designated on map by composite label indicating both overlying sediment cover and lower (older) unit, separated by slash (for example, Qms/Tm indicates that thin sheet of Qms 

overlies Tm)]

Artificial seafloor (late Holocene)—Pipelines on inner shelf, south of Gaviota marine terminal

Artificially modified seafloor (late Holocene)—Sandy seafloor crossed by very low relief (about 10 to 20 cm 

high), widely spaced (about 5 to 15 m apart), northeast-trending ridges, interpreted as trawling scars 

Marine nearshore and shelf deposits (late Holocene)—Mostly sand; ripples common. Found mainly on gently 

seaward-dipping shelf and on Gaviota sediment bar

Coarse-grained marine nearshore and shelf deposits (late Holocene)—Ranges from coarse sand and gravel to 

boulders. Found mainly on Gaviota sediment bar

Fine-grained marine shelf deposits (late Holocene)—Mostly clay, silt, and very fine sand. Found on gently 

seaward-dipping shelf, at depths of between about 50 to 70 m and about 90 m

Marine shelf scour depression (late Holocene)—Inferred to be coarse sand and gravel, in low-relief scour 

depression

Marine pockmarks (Holocene)—Sand and mud, in circular to elliptical pockmarks

Marine shelf slump deposits (Holocene)—Hummocky, sandy debris-flow deposits. Found on southeast flank of 

Gaviota sediment bar

Marine upper slope deposits (Holocene)—Predominantly clay, silt, and very fine sand; commonly bioturbated. 

Found below shelf break on seaward-dipping (about 5°) slope

Marine canyons and rills (Holocene)—Probably sand and mud; forms narrow, elongate, and shallow to deep 

channels or rills; cut into midshelf to outer shelf and slope and also upper part of Conception fan 

Marine shelf-sediment lobes (Holocene)—Predominantly sand to boulders(?). Found as two distinct, irregularly 

shaped lobes near east edge of map area, at water depths of 35 to 60 m

Asphalt deposits (Holocene)—Asphalt (tar); weathered and biodegraded oil derived from underlying or nearby 

natural hydrocarbon seeps. Found along and near axis of Molino Anticline

Bedrock, undivided (Pliocene and Miocene)—Mainly mudstone and siltstone. Probably consists of the Pliocene 

Pico and Repetto Formations, the lower Pliocene and upper Miocene Sisquoc Formation, and the Miocene 

Monterey Formation

Sisquoc Formation (early Pliocene and late Miocene)—Marine, tan- to white-weathering, diatomaceous 

mudstone and shale, conglomerate, and subordinate dolomite

Monterey Formation (Miocene)—Mainly siliceous and calcareous mudstone and shale 

ONSHORE GEOLOGIC AND GEOMORPHIC UNITS

[Units compiled from Dibblee (1988a,b); unit ages, which are from these sources, reflect local stratigraphic relations. In 

addition, some Quaternary units modified by C.W. Davenport on basis of analysis of 2004 ifSAR and 2009 lidar imagery]

Artificial fill (late Holocene)—Engineered and (or) nonengineered material deposited by humans

Beach deposits (late Holocene)—Unconsolidated, fine- to coarse-grained sand, pebbles, and boulders. Mapped in 

coastal band from shoreline to highest elevation of swash zone 

Active stream-channel deposits (late Holocene)—Active stream channels that contain unconsolidated sand, silt, 

and gravel deposits

Alluvium (late Holocene)—Alluvial deposits adjacent to active stream channels

Alluvial deposits, undivided (Holocene)—Sand, gravel, and silt deposits, adjacent to or near active stream 

channels

Alluvial fan deposits (Holocene)—Unconsolidated, heterogeneous layers of sand, silt, and gravel; relatively 

undissected. Internal contacts delineate individual alluvial fans

Colluvium (Holocene)—Loose to firm, unsorted sand, silt, clay, gravel, rock debris, and organic material; 

includes slope wash and valley fill; may contain numerous small landslides and (or) coalesced alluvial fans

Landslide deposits (Holocene and Pleistocene)—Deposits of diverse slope-movement processes; queried where 

identity is uncertain. Internal contacts delineate individual landslide bodies

Alluvial deposits, undivided (Holocene and Pleistocene)—Sand, gravel, and silt deposits. Mapped on gently 

sloping to level surfaces near stream channels 

Alluvial fan deposits (Holocene and Pleistocene)—Poorly consolidated silt, sand, and gravel deposits. Mapped 

either where older age is indicated by greater degree of dissection or where elevations are higher than that of 

adjacent Holocene alluvial fans. Internal contacts delineate individual alluvial fans

Alluvial deposits (Pleistocene)—Sand, gravel, and silt deposits; includes remnants of stream terraces and alluvial 

fans

Alluvial fan deposits (Pleistocene)—Discontinuous or highly dissected deposits of semiconsolidated, moderately 

to poorly sorted layers of silty clay, silt, sand, and gravel. Found adjacent to mountain fronts

Gravel, cobbles, and boulders (Pleistocene)—Fan and fanglomerate deposits that consist of gravel, cobbles, and 

boulders 

Marine-terrace deposits, undivided (Pleistocene)—Semiconsolidated sand and local gravel deposits, on uplifted 

marine-abrasion platforms along coast

Sisquoc Formation (early Pliocene and late Miocene)—Marine shale, claystone, and diatomite

Monterey Formation, undivided (Miocene)—Marine, predominantly well-bedded, siliceous chert, mudstone, 

shale, diatomite, and conglomerate breccia. Locally divided into three subunits

Conglomerate breccia (Miocene)—Siliceous and cherty shale detritus in tar-soaked sandstone matrix

Light-gray diatomite (Miocene)

Semisiliceous shale (Miocene)

Tranquillon Volcanics (Miocene)—Rhyolitic tuff breccia

Rincon Shale (early Miocene)—Marine shale or claystone 

Vaqueros Formation (late Oligocene)—Marine calcareous sandstone; queried where identity is uncertain. 

Includes one subunit

Sandstone and pebble conglomerate (late Oligocene) 

Sespe Formation, upper sandstone and mudstone unit (Oligocene)—Nonmarine sandstone, siltstone, and 

mudstone. Includes one subunit

Sandstone and pebble conglomerate (Oligocene) 

Alegria Formation (Oligocene)—Marine arkosic sandstone and silty claystone; queried where identity is 

uncertain 

Gaviota Formation (Oligocene and Eocene)—Marine arkosic sandstone, locally fossiliferous. Includes one 

subunit

Concretionary siltstone and claystone (Oligocene and Eocene)—Queried where identity is uncertain

Gaviota Formation and Sacate Formation, undivided (Oligocene and Eocene)—Marine sandstone and 

siltstone 

Sacate Formation (Eocene)—Marine arkosic sandstone that contains interbeds of micaceous, clayey shale. 

Includes one subunit

Predominantly shale (late Eocene)

Cozy Dell Shale (Eocene)—Marine micaceous shale

Matilija Sandstone (Eocene)—Marine arkosic sandstone; queried where identity is uncertain

Anita Shale (Eocene and Paleocene)—Marine, micaceous, clayey shale; includes foraminiferal claystone 

(informally known as “Poppin shale”)

Jalama Formation (Late Cretaceous)—Marine arkosic sandstone; includes three subunits 

Siltstone (Late Cretaceous)

Micaceous shale and siltstone (Late Cretaceous)

Arkosic sandstone with interbeds of micaceous shale (Late Cretaceous)

Ts

Tg

Tss

Tg-sa

Ta

Tspc

Tv

Tml

Tmcg

Kjsl

Kja

Tan

Tma

Tcd

Tm

Qc

Qal

Qyf

Qya

Qsc

Qb

af

Qmt

Qof

Qg

Qoa

Qf

Qa

Qls

Tsq

Tmls

Tr

Kjss

Kjsh

Tt

Tvsc

Tsp

Tgs

Qms

Qmsf

Qmsc

Qda

Qmp

af

Qas

Qmscl

Tbu

Qmcr

Tsq

Tm

aft

Qmsl

Qmsd

Tm

Tan

Ta

Tsp

Tv

Tcd

aft Qms Qmsc

Ts

Qmp

af Qmsf

Tbu

Pliocene

Pleistocene

Miocene

Oligocene

Eocene

Holocene

TERTIARY

QUATERNARY

Paleocene

CRETACEOUS

Tm

Kja

OFFSHORE GEOLOGIC AND GEOMORPHIC UNITS ONSHORE GEOLOGIC AND GEOMORPHIC UNITS

CORRELATION OF MAP UNITS

[See Description of Map Units (chapter 7, in pamphlet) for precise unit ages]

Qb Qsc

Qal

af Qya

Qda Qmsl Qmcr Qmscl Qas

Tsq Tsq

Qyf Qc

Qls

Qa Qf

Qoa Qof Qg Qmt

Tt

Tr

Tvsc

Tmls

Tmcg

Tml

Tspc

Tgs Tg

Tma

Kjsl

Kjss

Kjsh

Tss

Qmsd

 Late

Cretaceous

Tg-sa

120°30' 120° 119°30'

34°

34°30'

Limit of California’s

State Waters

Kilometers 0 5 10

Santa Barbara Channel

Area of

Map

Santa Barbara CALIF.

MAP LOCATION

Anacapa Is.

Santa Cruz Is.

Santa Rosa Is.

San Miguel Is.

1

U.S. Geological Survey;

2

California Geological Survey

Offshore and Onshore Geology and Geomorphology, Offshore of Gaviota Map Area, California

 By

Stephen R. Hartwell,1 Samuel Y. Johnson,1 and Clifton W. Davenport2

2018

ONE MILE = 0.869 NAUTICAL MILES

1 .5 0 1 KILOMETER

1000 0 1000 2000 3000 4000 5000 6000 7000 FEET

1 1/2 0 1 MILE

SCALE 1:24 000

APPROXIMATE MEAN BATHYMETRIC CONTOUR INTERVALS 10 METERS DECLINATION, 2018

MAGNETIC NORTH

12 / ° 1 2

TRUE NORTH

Offshore geology and geomorphology mapped by Samuel Y. 

Johnson and Stephen R. Hartwell, 2016. Onshore geology and 

geomorphology compiled by Clifton W. Davenport, 2014, from 

Dibblee (1988a,b). Bathymetric contours by Peter Dartnell, 2014

GIS database and digital cartography by Stephen R. Hartwell and 

Peter Dartnell 

Manuscript approved for publication February 12, 2018 

Onshore elevation data from National Oceanic and Atmospheric 

Administration (NOAA) Office for Coastal Management's Digital Coast 

(available at http://www.csc.noaa.gov/digitalcoast/data/coastallidar/) and 

from U.S. Geological Survey’s National Elevation Dataset (available at 

http://ned.usgs.gov/). Offshore shaded relief bathymetry from map on sheet 2, 

this report. California’s State Waters limit from NOAA Office of Coast Survey

Universal Transverse Mercator projection, Zone 10N

NOT INTENDED FOR NAVIGATIONAL USE

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south strand of Santa Ynez Fault

Molino Anticline

Ta

Tt

Ta

Tan

Ta

Ta

Tcd

Tma

Tm

Tml

Ts

Tr

Ta

Tcd

Kja

Tma

Tma

Tr

Tm

Tml

Tm

Tr

Tg

Tsq

Tsp

Tgs

Tr

Tma

Tsp

Ta

Tsp

Tg

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Tgs

Ts

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Ts

Tr

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Ts

Kjsh

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Tgs

Kjsh

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Tan

Tr

Tss

Ta

Tgs

Tml

Tcd

Tr

Tsp

Tsq

Tsp

Tr

Ta

Qls

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Tan

Tv

Kja

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Tml

Tr

Tcd

Tm

Kjsh

Qls

Tr

Tcd

Tgs

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Tcd

Tm

Qf

Tgs

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Qof

Ts

Tg

Qal

Tr

Tgs

Ts

Tgs

Ts

Tr

Tgs

Tr

Kja

Tsq

Tcd

Ts

Tr

Tv

Tg

Tr

Qg

Qmt

Tr

Tcd

Tr

Tgs

Tr

Tm

Tr

Qof

Qg

Qf

Qls

Qls

Tr

Qof

Tsq

Qf

Tma

Tg

Tm

Ta

Tg

Qal

Tml

Tr

Tsp

Tgs

Tml

Kjsl

Tan

Tv

Tsp

Tg

Qal

Qls

Tsq

Tm

Tan

Tr

Tcd

Tgs

Tv

Tg

af

Ta

Tgs

Tg

Tv

Qf

Kjsh

Qmt

Tr

Tm

Tml

Tr

Qf

Ta

Tsq

Tsq

Qls

Tml

Tcd

Tml

Tm

Tr

Tr

Tr

Tgs Tgs

Tg

Kjsh

Qf

Tm

Qls

Tr

Tml

Kjsh

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Tg

Tg

Qmt

Tan

Tml

Tss

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Tgs

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Tma

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Tm

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Tr

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Tg

Tv

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Tv

Tan

Qls

Tmls

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Qls

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Tr

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Tan

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Tvsc

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Qls

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Tgs

Tm

Tgs

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Tml

Tgs

Tgs

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Qls

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Qa

Qc

Qal

Qls

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Tr

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Ts

Qoa

Qls

Tml

Qal

Kjss

Kja

Qls

Qls

Qof

Qc

Qls

Tma

Qls

Kjsh

Ta

Qa

Tgs

Qc

Tan

Qls?

Qmt

Tan

Tr

Qa

Tsp

Qmt

Tsq

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Tr

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Qls

Qls

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Tan

Qoa

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Kjss

Tg

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Qls

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Qls

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Tma

Qls

Qls

Ta

Qls

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Qc

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Qls

Qal

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Tv

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Qls

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Ts

Tg

Tan

Tgs

Qls

Qls

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Qls

Qc

Qls

Qmt

Tmcg

Tma

Qal

Qls

Tg

Qls

Qyf

Tcd

Qal

Qmt

Qal

Tml

Qls?

Tv

Qal

Tgs

Qal

Ts

Tg-sa

Qsc

Qal

Tv

Qsc

Qsc

Qsc

Tsq

Qsc

Tm

Ta

Qsc

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Qsc

Qc

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Ts

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Qc

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Qc

Tv

Tml

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Tml

Tsq

Qls

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Qls

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Qmt

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Tmls

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Qc

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Tma

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Qc

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Qls

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Qc

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Qls

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Qls

Qls

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Qc

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Tg

Qls

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Qc

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Qc

Qc

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Tma

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Qls

Qls

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Tml

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Qls

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Qa

Qal

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Qal

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Qls

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Qc

Qc

Qls

Qls

Qal

Qls

Qc

Qls

Qls

Qmt

Qsc

Tml

Qc

Qal

Qf

Tg

Qc

Qal

Qls

Qc

Qc

Qls

Qc

Qal

Qc

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Qls

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Tml

Qls

Tml

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Qls

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Qls

Qc

Qc

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Qc

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Qc

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Qc

Qc

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Qls

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Tsp

Qal

Qls

Qc

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Qc

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Qc

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Qya

Qyf

Qls

Qls

Qls

Qls

Qls

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Qc

Qc

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Qyf

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Qls

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Qc

Qc

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Qc

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Qls

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Qc

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Qc

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Qyf

Tan

Kja Kja

Tmls

Tmls

Tmls

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Qf

Tmls

Qc

Qf Qyf

Qb

Qc

Qc Qal

Qal

Qal Qal

af

Qal

Qal

Qc

Qoa

Qls?

Qls

Qls

Tmls

Qsc

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Tbu

Tm

Tbu

Tsq

Qmp

Qms

Qas

Qms/Tsq

Qms/Tsq

Qmp

Qda

Qms

Qmp

Qmsl Qmsl

Qmsl

Qmsl

Qmsl

Qmsl

Qms/Tbu

Qmsd

Qmsl

Qmsf

Qmcr

Tbu

Qmp

Qmscl

Tbu

Tsq

af

Tbu

Qmsc

Tm

Qmcr

Tbu

Qmp

Qms

af

Tsq

Tbu

Qms

Tbu

Qms

Qmsc

Qmp

Qms/Tsq

Tm

Qmp

Qms

Qmp

Qmsf

Qmsc

Qas

Qas

Qmscl

Tbu

Qas

Qms

Tbu

Qmcr

Qmsc

Qmp

Qmcr

Qmp

Tbu

Qda

Qms

Qmsc

Qmsc

aft

Qas

Qmcr

Qas

Tbu

Qmcr

Qmsc

Tsq

Tbu

Qmsc

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Qas

Qmsc

Qms/Tsq

Qas

Tsq

Qmp

Qmp

Qmsc

Qms/Tsq

Qmcr

Qmp

Qmp

Qmp

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Qmsc

Qmsc

aft

Qmp

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Tsq

Tsq

Tsq

Tsq

Tsq

Qms/Tsq

Qms

Tbu

QmsTbu

Qms

Qms

Tbu

Qms

Qmsc

Qmsc

Qmsc

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Qms/Tm

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Qmcr

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Tm

Tm

Qms

Qms

Qmsc

Qmsc

Tsq

Tsq

Tsq

Qms/Tsq

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Qda

Qms/Tsq

Government Point Syncline

Tvsc

Tvsc

Tvsc

120°15'

120°15'

120°20'

120°20'

34°30'

34°30'

34°25'

34°25'

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Open-File Report 2018–1023

Sheet 9 of 9

Pamphlet accompanies map

U.S. Department of the Interior

U.S. Geological Survey