Marine geology of Tomales Bay, Central California

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: Calvin Crowell Daetwyler, Jr.

Publication_Date: 1965

Title: Marine geology of Tomales Bay, Central California

Geospatial_Data_Presentation_Form: Paper

Publication_Information:

Publication_Place: San Diego, CA

Publisher: University of California, San Diego

Other_Citation_Details:

Funding from an American Chemical Society Donation Grant and National Science Foundation Grant 2550

Description:

Abstract:

"Tomales Bay is a submerged rift valley lying along the axis of the northwest-trending, seismically active San Andreas fault zone. Protected bay sediments are being deposited in a narrow, elongated, structural depression, characterized by known strike-slip faulting in historic times. The primary objective of this investigation is to determine the relative effects of normal depositional processes and contemporaneous strike-slip faulting on the Recent sediment facies, thickness, distribution, and depositional history in Tomales Bay. The stratigraphic succession and major internal structure of the Recent sediments in the southern two-thirds of the bay were determined by combining an acoustic-reflection survey (Sonoprobe) with lithologic data obtained from cores and test borings. Lithologic variations of the Tomales Bay surface sediments are attributed to 1.) the location and character of the sediment sources and 2.) the dispersal of sediment by tidal currents. Sandy sediments, supplied to the bay entrance by southerly longshore currents, have been subsequently redistributed throughout the northern third of the bay by tidal currents. Within this area of sand deposition, further textural subdivisions can be made on the basis of size-sorting relationships and size-frequency distributions. A textural transition zone marks the boundary between the sandy sediments and the fine-grained homogeneous sediments of the remaining two-thirds of the bay. Large quantities of sediment fill have been deposited in historic times and are situated near the mouths of Walker and Lagunitas Creeks, which have supplied the fine-grained sediment to the bay. The subaerial rift valley, prior to the Late Wisconsin rise in sea level, contained features of fault morphology. A prominent, discontinuous, center rift ridge was present throughout the valley. When developed this ridge divided the valley into two topographically lower segments elongated parallel to the axis of the San Andreas fault zone. During the initial post-Wisconsin transgression, a basal transgressive facies was deposited locally over the pre-transgressive surface. Sand was transported southward from Bodega Bay and a constricting sand spit was formed southeast of Hog Island. South of this spit, muds were deposited and a mudflat and channel system developed. As sea level continued to rise, the entrance to Tomales Bay was gradually filled by sand. A new bay mouth spit (Sand Point) began to form. The formation of this feature at the bay entrance decreased the sand supplied to the southern bay. The southernmost sand spit was gradually transgressed and younger muds began to fill in the former tidal channels and cover the older mudflats. Small depressions, found along the bay margins south of Pelican Point, are the relicts of former tidal channels and are not related to seismic activity. Locations of several fault traces are inferred from vertical separations of the pre-transgressive surface. Net slip of the fault displacements was not determined since clear lines of displacement were not established. Factors of basin geometry, a rising sea level, and the rates of sediment supply and dispersal, have been more important than active strike-slip faulting in determining the stratigraphy and internal structure of the Tomales Bay Recent sediments."

Purpose:

"The primary objective of this investigation is to determine the effects of recurrent contemporaneous strike-slip faulting and normal depositional processes on the Recent sediment facies, thickness, distribution and depositional history in Tomales Bay. Specific objectives are: 1.) to explain the distribution and internal structure of the Recent sediments in terms of their immediate source, and the dominant processes controlling their dispersal and deposition, and 2.) to evaluate the effects of faulting on the Recent sediments being deposited in this seismically active structural setting."

Supplemental_Information:

Data digitized by the USGS for inclusion into usSEABED. (<http://walrus.wr.usgs.gov/usseabed>)

Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 1965

Currentness_Reference: Publication date

Status:

Progress: Complete

Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -122.9774

East_Bounding_Coordinate: -122.8529

North_Bounding_Coordinate: 38.2310

South_Bounding_Coordinate: 38.1051

Keywords:

Theme:

Theme_Keyword_Thesaurus: None

Theme_Keyword: University of California San Diego

Theme_Keyword: Snapper grabs

Theme_Keyword: Gravity cores

Theme:

Theme_Keyword_Thesaurus: ISO 19115 Topic Category

Theme_Keyword: Oceans and Estuaries

Theme_Keyword: Location

Theme_Keyword: GeoscientificInformation

Theme:

Theme_Keyword_Thesaurus:

NASA/Global Change Master Directory (GCMD) Earth Science Keyword. Version 5.3.3

Theme_Keyword: Marine Sediments

Theme_Keyword: Sediment Composition

Theme_Keyword: Sedimentary Structures

Theme_Keyword: Sedimentary Textures

Theme_Keyword: Terrigenous Sediments

Place:

Place_Keyword_Thesaurus: Geographic Names Information System (GNIS)

Place_Keyword: Tomales Bay

Place_Keyword: California, State of

Access_Constraints: Thesis available at the USGS library and other libraries

Use_Constraints:

Cite Calvin C. Daetwyler Jr. and the University of California San Diego as the originators of the data.

Point_of_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization:

Scripps Institute of Oceanography, University of California San Diego

Contact_Address:

Address_Type: Physical

Address: 9500 Gilman Drive

City: La Jolla

State_or_Province: CA

Postal_Code: 92093 0223

Contact_Voice_Telephone: 858 534 3624

Browse_Graphic:

Browse_Graphic_File_Name: Daetwyler_PhD_1965

Browse_Graphic_File_Description:

Screen grab of GIS-produced sample distribution, with bathymetry and land for reference.

Browse_Graphic_File_Type: JPG

Data_Set_Credit:

C. Daetwyler Jr. for collection and analysis of data. For inclusion into usSEABED, digitization: Jennifer Mendonca (USGS); Formatting corrections: Jane Reid (USGS) and Chris Jenkins (University of Colorado)

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

No estimate made for the accuracy of the data in the original report. Data digitized by the USGS and partners were visually compared to the source data, and corrected. Where appropriate, data were tested for completeness using MS Excel. Locations checked using GIS.

Logical_Consistency_Report:

Data fall within normal ranges for sediment percents, statistics, and other sediment parameters.

Completeness_Report:

For inclusion into usSEABED, appendix I (location of samples), Appendix II (grain size data), Appendix III (lithologic description of cores) and Appendix IV (Sound speed, density, porosity, and grain-size data, core 49 and 50) were completely digitized. Appendix V (Lithologic description of Merle Lawson water well No. 2 and Tomales Bay test borings) was not digitized.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

Navigational technique not noted in report. Locations given to one-half seconds (degree, minute, second).

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report: Water depths not noted in report.

Lineage:

Process_Step:

Process_Description:

Split samples were treated with 10 per cent hydrogen peroxide to remove organic matter, dispersed in the presence of Ca2+ ions by 0.005 molal sodium oxalate and 0.062 molal sodium carbonate. Wet sieved on a 0.062 mm sieve. When necessary, the size fraction larger than 2.0 mm was also separated by wet sieving. A standard pipette analysis was made of the fine fractions. The sand fraction was reduced to a subsample of a few grams with an Otto microsplit. The size distribution was determined by a continuous-recording sedimentation balance developed at SIO (van Andel, 1964). For inclusion into usSEABED, gravel values > 0 for 14 grab samples were integrated and sand/silt/clay values recalculated. Mean and median grainsize values and standard deviations (sorting) for those samples are not used.

Source_Used_Citation_Abbreviation: Van Andel, 1964

Process_Date: Unknown

Source_Produced_Citation_Abbreviation: Daetwyler_PhD_1965

Process_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization:

Scripps Institute of Oceanography, University of California San Diego

Contact_Address:

Address_Type: Physical

Address: 9500 Gilman Dr

City: La Jolla

State_or_Province: CA

Postal_Code: 92093 0223

Contact_Voice_Telephone: 858 534 3624

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Vector

Point_and_Vector_Object_Information:

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: Point

Point_and_Vector_Object_Count: 124

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Geographic:

Latitude_Resolution: 0.00014

Longitude_Resolution: 0.00014

Geographic_Coordinate_Units: Decimal degrees

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: Point

Entity_Type_Definition: SDTS point

Entity_Type_Definition_Source: Source report

Attribute:

Attribute_Label: Gravel

Attribute_Definition: Gravel

Attribute_Definition_Source: Wentworth 1932

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0

Range_Domain_Maximum: 29.9

Attribute_Units_of_Measure: Percent

Attribute_Measurement_Resolution: 0.1

Attribute:

Attribute_Label: Sand

Attribute_Definition: Sand

Attribute_Definition_Source: Wentworth 1932

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.2

Range_Domain_Maximum: 100

Attribute_Units_of_Measure: Percent

Attribute_Measurement_Resolution: 0.1

Attribute:

Attribute_Label: Silt

Attribute_Definition: Silt

Attribute_Definition_Source: Wentworth 1932

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.5

Range_Domain_Maximum: 68.4

Attribute_Units_of_Measure: Percent

Attribute_Measurement_Resolution: 0.1

Attribute:

Attribute_Label: Clay

Attribute_Definition: Clay

Attribute_Definition_Source: Wentworth 1932

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1.3

Range_Domain_Maximum: 75.3

Attribute_Units_of_Measure: Percent

Attribute_Measurement_Resolution: 0.1

Attribute:

Attribute_Label: Mud

Attribute_Definition: Mud

Attribute_Definition_Source: Wentworth 1932

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0

Range_Domain_Maximum: 11.8

Attribute_Units_of_Measure: Percent

Attribute_Measurement_Resolution: 0.1

Attribute:

Attribute_Label: Mean

Attribute_Definition: Mean of grainsize distributions

Attribute_Definition_Source: Inman, 1952

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1.6

Range_Domain_Maximum: 7.28

Attribute_Units_of_Measure: Phi

Attribute_Measurement_Resolution: 0.01

Attribute:

Attribute_Label: Dev.

Attribute_Definition: Standard deviation of grainsize distribution (sorting)

Attribute_Definition_Source: Inman, 1952

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.24

Range_Domain_Maximum: 1.91

Attribute_Units_of_Measure: Phi

Attribute_Measurement_Resolution: 0.01

Attribute:

Attribute_Label: Median

Attribute_Definition: Median grainsize

Attribute_Definition_Source: Inman, 1952

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1.58

Range_Domain_Maximum: 8.95

Attribute_Units_of_Measure: Phi

Attribute_Measurement_Resolution: 0.01

Attribute:

Attribute_Label: Porosity

Attribute_Definition: Porosity of sample

Attribute_Definition_Source: Source report

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 63.7

Range_Domain_Maximum: 76.

Attribute_Units_of_Measure: Phi

Attribute_Measurement_Resolution: 0.1

Attribute:

Attribute_Label: Bulk density

Attribute_Definition: Wet bulk density

Attribute_Definition_Source: Source report

Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1.41

Range_Domain_Maximum: 1.62

Attribute_Units_of_Measure: Gm/cc

Attribute_Measurement_Resolution: 0.01

Attribute:

Attribute_Label: Text

Attribute_Definition: Descriptive text

Attribute_Definition_Source: Source report

Attribute_Domain_Values:

Unrepresentable_Domain: Descriptive text including color and Munsell code

Attribute:

Attribute_Label: Shepard class

Attribute_Definition: Location of sample on the sand-silt-clay ternary

Attribute_Definition_Source: Shepard 1954

Attribute_Domain_Values:

Unrepresentable_Domain: Textural name representing position on sand-silt-clay ternary.

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization:

Scripps Institute of Oceanography, University of California San Diego

Contact_Address:

Address_Type: Physical

Address: 9500 Gilman Drive

City: La Jolla

State_or_Province: CA

Postal_Code: 92093 0223

Contact_Voice_Telephone: 858 534 3624

Resource_Description: C.C. Daetwyler, Jr's PhD thesis, 1965

Distribution_Liability:

Although this dataset has been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data. Users of the data should be aware of limitations of the data due to possible imprecision due to navigational inaccuracies and limitations of the statistical data.

Standard_Order_Process:

Non-digital_Form: Report is available at some libraries.

Fees: None

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey

Contact_Address:

Address_Type: Mail and physical

Address: 345 Middlefield Road

City: Menlo Park

State_or_Province: CA

Postal_Code: 94025

Contact_Voice_Telephone: 650.329.5026

Contact_Electronic_Mail_Address: men_lib@usgs.gov

Resource_Description: Daetwyler PhD 1965

Distribution_Liability:

Although this dataset has been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data. Users of the data should be aware of the limitations of the data due to possible imprecision due to navigational inaccuracies, statistical limitations, and digitizing errors.

Standard_Order_Process:

Non-digital_Form:

Report is available for viewing or checkout at the USGS library, Menlo Park, and at other libraries.

Fees: None

Technical_Prerequisites: None

Available_Time_Period:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 1965

Metadata_Reference_Information:

Metadata_Date: 2005

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: U.S. Geological Survey

Contact_Person: Jane A. Reid

Contact_Position: Geologist

Contact_Address:

Address_Type: Physical and mail

Address: 400 Natural Bridges Drive

City: Santa Cruz

State_or_Province: CA

Postal_Code: 95060

Contact_Voice_Telephone: 831-427-4727

Contact_Electronic_Mail_Address: jareid@usgs.gov

Contact_Instructions: Email preferred

Metadata_Standard_Name: CSDGM Version 2

Metadata_Standard_Version: FGDC-STD-001-1998

Metadata_Access_Constraints: None

Metadata_Use_Constraints:

Metadata was written by a user of the data. Any information contained in the physical report is authoritative and supercedes any information given here.