Online Links:
| Value | Definition |
|---|---|
| contact, certain | Observed contact |
| fault, approx. located | Fault whose position is not precisely known |
| fault, certain | Observed fault |
| fault, concealed | Concealed fault whose position is inferred |
| map boundary, | Boundary of mapped area |
| water boundary, | Boudary of bodies of water |
| Value | Definition |
|---|---|
| f.a., anticline, approx. located | Anticlinal fold axis whose position is not precisely known |
| f.a., anticline, certain | Observed anticlinal fold axis |
| f.a., anticline, concealed | Concealed anticlinal fold axis whose position is inferred |
| f.a., overturned syncline, approx. | Overturned synclinal fold axis whose position is not precisely known |
| f.a., syncline, approx. located | Synclinal fold axis whose position is not precisely known |
| f.a., syncline, certain | Observed synclinal fold axis |
| fault, approx. located | Fault whose position is not precisely known |
| fault, certain | Observed fault |
| fault, concealed | Concealed fault whose position is inferred |
| fault, inferred | Fault whose position is inferred |
| fault, inferred, queried | Fault whose position is inferred and questionable |
| map boundary | Boundary of mapped area |
| normal fault, approx. located | Normal fault whose position is not precisely known |
| normal fault, certain | Observed normal fault |
| normal fault, concealed | Concealed normal fault whose position is inferred |
| reverse fault, approx. located | Reverse fault whose position is not precisely known |
| reverse fault, certain | Observed reverse fault |
| reverse fault, concealed | Concealed reverse fault whose position is not precisely known |
| reverse fault, inferred | Reverse fault whose position is inferred |
| s.s. fault, r.l. approx. located | Right-lateral strike-slip fault whose position is not precisely known |
| s.s. fault, r.l. certain | Right-lateral strike-slip fault whose position is certain |
| s.s. fault, r.l., concealed | Right-lateral strike-slip fault whose position is concealed and inferred |
| thrust fault, approx. located | Thrust fault whose position is not precisely known |
| thrust fault, certain | Observed thrust fault |
| thrust fault, concealed | Concealed thrust fault whose position is inferred |
| thrust fault, concealed, queried | Concealed thrust fault whose position is questionable |
| water boundary, | Boundary of a body of water |
| Value | Definition |
|---|---|
| Qar | Artificial deposits (Holocene) |
| Qu | Surficial deposits, undivided (Holocene and Pleistocene) |
| Qls | Landslide deposits (Holocene and Pleistocene) |
| Qt | Terrace deposits (Holocene(?) and Pleistocene) |
| Qoa | Older alluvium (Pleistocene) |
| Tsv | Silicic volcanic rocks (Miocene or younger) |
| KJqd | Quartz diorite (Jurassic or younger) |
| KJf | Undivided Franciscan complex (Jurassic and Cretaceous) |
| Kfn | Novato Quarry terrane of Blake and others (1984) (late Cretaceous) |
| KJfs | Franciscan sandstone, undivided (Late Jurassic to Late Cretaceous) |
| KJfm | Franciscan melange (Late Jurassic and/or Early Cretaceous) |
| KJfe | Eylar Mountain terrane of Crawford (1976) (Late Jurassic and/or Early Cretaceous) |
| KJfg | Franciscan greenstone (Late Jurassic and/or Early Cretaceous) |
| Tbp | Bald Peak Basalt (late Miocene) |
| Tst | Siesta Formation (late Miocene) |
| Tmb | Moraga Formation (late Miocene) |
| Tor | Orinda Formation (late Miocene) |
| Tcc | Claremont Chert (middle to late Miocene) |
| Tush | Unnamed gray mudstone (early Miocene) |
| Tsm | Unnamed glauconitic mudstone (Oligocene(?) and Miocene) |
| Tes | Unnamed mudstone (Eocene) |
| Ta | Unnamed glauconitic sandstone (Paleocene) |
| QTl | Livermore gravels (Pliocene and Pleistocene) |
| Tmll | Lower member - Mullholland Formation of Ham (1952) (late Miocene and Pliocene) |
| Tus | Unnamed sedimentary and volcanic rocks (late Miocene) |
| Tn | Neroly Sandstone (late Miocene) |
| Tbr | Briones Formation (middle and late Miocene) |
| Tbi | I member - Briones Formation (middle and late Miocene) |
| Tbg | G member - Briones Formation (middle and late Miocene) |
| Tbgc | Conglomerate-G member - Briones Formation (middle and late Miocene) |
| Tbgl | Limestone-G member - Briones Formation (middle and late Miocene) |
| Tbf | F member - Briones Formation (middle and late Miocene) |
| Tbe | E member - Briones Formation (middle and late Miocene) |
| Tbd | D member - Briones Formation (middle and late Miocene) |
| Tro | Rodeo Shale, Hambre Sandstone, Tice Shale, and Oursan Sandstone, undivided (middle Miocene) |
| Tr | Rodeo Shale (middle Miocene) |
| Th | Hambre Sandstone (middle Miocene) |
| Tt | Tice Shale (middle Miocene) |
| To | Oursan Sandstone (middle Miocene) |
| Tcs | Claremont Shale (middle Miocene) |
| Ts | Sobrante Sandstone (middle Miocene) |
| Ku | Unnamed sedimentary rocks (Late Cretaceous, Cenomanian and Turonian) |
| QTl | Livermore gravels (Pliocene and Pleistocene) |
| Tgvt | Green Valley and Tassajara Formations of Conduit (1938), undivided (Pliocene and Miocene) |
| Tn | Neroly Sandstone (late Miocene) |
| Tc | Cierbo Sandstone (late Miocene) |
| Kss | Unnamed sandstone (Late Cretaceous, Campanian and Maastrichtian) |
| Kslt | Unnamed siltstone (Late Cretaceous, Campanian) |
| Ku | Unnamed mudstone (Late Cretaceous, Cenomanian and Turonian) |
| Jb | Massive basalt and diabase - Coast Range ophiolite (Jurassic) |
| Jgb | Gabbro and diabase - Coast Range ophiolite (Jurassic) |
| sp | Serpentinite - Coast Range ophiolite (Jurassic) |
| Tol | Oro Loma Formation of Briggs (1953) (Pliocene) |
| Tn | Neroly Sandstone (late Miocene) |
| Tc | Cierbo Sandstone (late Miocene) |
| Kel | Unit E, lower member (Late Cretaceous) - Great Valley sequence |
| Kcu | Upper member, Unit C - Sandstone and shale (Late Cretaceous) - Great Valley sequence |
| Kcm | Middle member, Unit C - Sandstone and shale (Late Cretaceous) - Great Valley sequence |
| Kcl | Lower member, Unit C - Sandstone and shale (Late Cretaceous) - Great Valley sequence (Cretaceous) |
| Kbsh | Unit B, shale member (Late Cretaceous) - Great Valley sequence |
| QTi | Irvington Gravels of Savage (1951) (Pliocene(?) and Pleistocene) |
| Tv | Unnamed volcanic rocks (late Miocene and/or Pliocene) |
| Tsh | Unnamed shale, sandstone, chert and dolomite (early Miocene) |
| Ttls | Gray, algal limestone - Tolman Formation of Hall (1958) (Eocene?) |
| Tts | Dark gray to dark greenish-gray - Tolman Formation of Hall (1958) (Eocene?) |
| Tps | Unnamed siltstone and sandstone (Paleocene) |
| Kp | Pinehurst Shale (Late Cretaceous, Campanian) |
| Kr | Redwood Canyon Formation (Late Cretaceous, Campanian) |
| Ksc | Shephard Creek Formation (Late Cretaceous, Campanian) |
| Kcv | Unnamed sandstone, conglomerate, and shale of the Castro Valley area (Late Cretaceous, Turonian and younger(?)) |
| Ko | Oakland Sandstone (Late Cretaceous, Cenomanian and/or Turonian) |
| Kjm | Joaquin Miller Formation (Late Cretaceous, Cenomanian) |
| Ksh | Unnamed shale (Early Cretaceous) |
| Ks | Unnamed sandstone and shale (Cretaceous) |
| KJk | Knoxville Formation (Late Jurassic and Early Cretaceous) |
| Jsv | Keratophyre and quartz keratophyre (Late Jurassic) |
| Jpb | Pillow basalt, basalt breccia, and minor diabase - Coast Range ophiolite (Jurassic) |
| Jb | Massive basalt and diabase - Coast Range ophiolite (Jurassic) |
| Jgb | Gabbro - Coast Range ophiolite (Jurassic) |
| Tss | Unnamed sandstone (late Miocene and/or Pliocene) |
| Ks | Unnamed sandstone and shale (Cretaceous) |
| Ttem | Temblor Sandstone (middle Miocene) |
| Tn | Neroly Sandstone (late Miocene) |
| Tte | Tesla Formation (Eocene) |
| Ksuh | Unnamed shale (Late Cretaceous) - Great Valley sequence |
| Ksus | Unnamed sandstone (Late Cretaceous) - Great Valley sequence |
| Ksu | Unnamed sandstone and shale (Late Cretaceous) - Great Valley sequence |
| Kkh | Horsetown Formation of Huey (1948) (Early Cretaceous) |
| fs | Franciscan metagrawake and shale (Lower Tertiary? and Upper Cretaceous) |
| fc | Franciscan chert (Lower Tertiary? and Upper Cretaceous) |
| fg | Franciscan greenstone (Lower Tertiary? and Upper Cretaceous) |
| H2O | Surface Water |
| Tsms | Brown siltstone and fine-grained sandstone (Oligocene(?) and Miocene) |
| Kfgm | Fine grained quartz diorite |
| Kd | Great Valley sequence, Unit D - Sandstone (Late Cretaceous) |
| Kds | Great Valley sequence, Unit D - Shale Member (Late Cretaceous) |
| Tccs | Claremont Formation, Sandstone and Siltstone Member (middle Miocene) |
| Kcus | Great Valley sequence, Upper Member Unit C - Sandstone (Late Cretaceous) |
| gb | Gabbro |
| Tmls | Sandstone Marker Beds of the Mullholland Formation of Ham (1952) (late Miocene and Pliocene) |
| Tusl | Unnamed conglomerate, sandstone, siltstone, and limestone (late Miocene) |
| Tgvtt | Green Valley and Tassajara Formation - Tuff Marker Bed (Pliocene and Miocene) |
| Kc | Unnamed pebble to boulder conglomerate (Late Cretaceous, Cenomanianand and Turonian) |
| KJkc | Pebble to cobble conglomerate of the Knoxville Formation (Late Jurassic and Early Cretaceous) |
| Torv | Orinda Formation, Plagioclase porphyrytic dacite (Late Miocene) |
| Tlp | Unnamed freshwater limestone (Pliocene(?)) |
| Tnc | Neroly Sandstone, locally mapped pebble conglomerate (late Miocene) |
| fl | Franciscan marble (Late Jurassic and/or Early Cretaceous) |
| sc | Silica-carbonate rock, a subunit of serpentinite |
| Value | Definition |
|---|---|
| contact, certain | Observed contact |
| contact, concealed | Concealed contact whose position is inferred |
| contact, approx. located | Contact whose position is not precisely known |
| contact, inferred | Contact whose position is inferred |
| fault, certain | Observed fault |
| fault, approx. located | Fault whose position is not precisely known |
| fault, concealed | Concealed fault whose position is inferred |
| fault, concealed, queried | Concealed fault whose position is inferred and questionable |
| fault, inferred | Fault whose position is inferred |
| fault, inferred, queried | Fault whose position is inferred and questionable |
| s.s. fault, r.l., approx. located | Right-lateral strike-slip fault whose position is not precisely known |
| s.s. fault, r.l., certain | Observed right-lateral strike-slip fault |
| s.s. fault, r.l., concealed | Concealed right-lateral strike-slip fault whose position is inferred |
| thrust fault, approx. located | Thrust fault whose position is not precisely known |
| thrust fault, certain | Observed thrust fault |
| thrust fault, concealed | Concealed thrust fault whose position is inferred |
| thrust fault, concealed, queried | Concealed thrust fault whose position is questionable |
| tuff bed | Location of a tuff bed |
| water boundary | Boundary of a body of water |
| map boundary | Boundary of mapped area |
| Value | Definition |
|---|---|
| f.a., anticline, approx. located | Anticlinal fold axis whose position is not precisely known |
| f.a., anticline, certain | Observed anticlinal fold axis |
| f.a., anticline, concealed | Concealed anticlinal fold axis whose position is inferred |
| f.a., overturned syncline, approx. | Overturned synclinal fold axis whose position is not precisely known |
| f.a., syncline, approx. located | Synclinal fold axis whoes position is not precisely known |
| f.a., syncline, certain | Observed synclinal fold axis |
| Value | Definition |
|---|---|
| approx bedding | Bedding orientation that is not precise |
| bedding | Bedding orientation |
| bedding w/tops | Bedding with tops orientation |
| crumpled bedding | Crumpled bedding orientation |
| flat bedding | Bedding whose dip is zero |
| foliation | Foliation orientation |
| foliation and bedding | Foliation and bedding orientation |
| joint | Joint orientation |
| ot bedding | Overturned bedding orientation |
| ot bedding w/tops | Overturned bedding with tops orientation |
| vert bedding | Bedding orientation whose dip is 90 degrees |
| vert bedding w/tops | Bedding with tops orientation whose dip is 90 degrees |
| vert foliation | Foliation orientation whose plunge is 90 degrees |
| vert foliation and bedding | Foliation and bedding orientation whose dip and plunge are 90 dgrees |
Coverage FAULT.AAT - fault name Attribute name - FNAME Fault names include: Arroyo Aguague fault Calaveras fault Chabot fault Dresser fault Greenville fault Hayward fault Las Positas fault Mill Creek fault Miller Creek fault Mission fault Moraga fault Palomares fault Pirate Creek fault Sheridan Creek fault South Las Positas fault Stonybrook fault Verona fault Warm Springs fault Williams fault
We are grateful to Kristin R. McDougall, William V. Sliter, David Bukry, John A. Barron, and William P. Elder of the U.S. Geological Survey for the paleontologic determinations necessary to help establish the ages of rocks in Alameda County. Scott D. Hill, Superintendent of Watershed, kindly provided access to lands owned by the East Bay Regional Park District. Leo T. Bauer, Alameda Division Manager, provided access to lands owned by the San Francisco Water Department. G. Doug Myron, U.S. Geological Survey, arranged for access to some of the private land in the study area. Carl M. Wentworth, Todd T. Fitzgibbon, and Geoffrey A. Phelps graciously provided assistance with Alacarte and ARC/INFO. James J. Lienkaemper shared some of his knowledge of the creeping strand of the Hayward fault, and David. H. Oppenheimer provided maps showing the location of epicenters. Larry J. Dickerson and John M. Parker, U.S. Geological Survey volunteers, provided extensive support in the field. We are grateful to AmeriCorps for sponsoring Dickerson, Parker, and Brabb.
The data are released in a preliminary digital form to provide an opportunity for regional planners, local, state, and federal agencies, teachers, consultants, and others interested in geologic data to have the new data long before a traditional paper map is published.
Are there legal restrictions on access or use of the data?Access_Constraints: none
Use_Constraints: none
This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
This database, identified as "Preliminary geologic map emphasizing bedrock formations in Alameda County, California: A digital database," has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.
| Data format: | Faults, depositional contacts, and rock unit identities, Fold axes, strike and dip information, and base maps in format ARCE (version 6.x) |
|---|---|
| Network links: |
http://pubs.usgs.gov/of/1996/of96-252/al_g1.tar.Z |