Geology of the onshore part of San Mateo County, California: A digital database

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Description This digital map database, compiled from previously published and unpublished data, and new mapping by the authors, represents the general distribution of bedrock and surficial deposits in San Mateo County. Together with the accompanying text, it provide
Originators Brabb, Earl E.; Graymer, Russell W.; and Jones, D. L.
Publication U.S. Geological Survey Open-File Report 98-137

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Overview of attributes

Grass Lake Sample Number:  A unique number assigned to a sample
regardless ot sample type
Sample box no.:  A unique sample number assigned to samples put
into plastic cubes for magnetic mineral studies.  The volume of
each cube is 3.2 cubic centimeters.
Vial no.:  A unique sample number assigned to sediment sample put
into vials.
Drive no.:  Identifies location in the core.  The core was divided
into drives numbered sequentially starting with 1 at the top.
Some drives have been further divided into slugs indicated by
letters, starting with A at the top of the drive.
Drive depth:  The depth in meters of the top of the drive from the
Depth interval of sample:  The depth range of the sample within
the drive.
Sample depth within drive (cm):  Midpoint of the depth interval in
Sample depth within drive (m):  Midpoint of depth interval in
Sample depth in core (m):  Sample depth within drive (m) plus
depth of drive from top of core.
Sample density (kg/m3):  Density of sample calculated from the
mass of the dried box samples used in magnetic mineral studies.
Declination:  Declination of the characteristic magnetization, clockwise from geographic north.
Inclination   The inclination of the characteristic magnetization.
NRM:  Natural Remanent Magnetization in Am2/kg.
Demag. Interval:  The demagnetization interval over which both
Declination and Inclination were calculated.
Number of Points used in linear fit:  Number of points used to
create best fit line.
Subjective quality:  A subjective grade (a is best, c the worst)
given to the orthogonal vector diagrams from which the best fit
line was calculated.
MSLF:  Low-frequency magnetic susceptibility in m3/kg.
FDMS:  Frequency-dependent magnetic susceptibility in percent.
ARM:  Anhysteretic remanent magnetization in Am2/kg.
IRM (1.2T):  Isothermal remanent magnetization from induction in a
1.2 tesla field at room temperature.  Expressed in Am2/kg.
IRM (-.3T):  Isothermal remanent magnetization from induction in
a -0.3 tesla field at room temperature. Expressed in Am2/kg.
HIRM:  Hard isothermal remanent magnetization:  HIRM is calculated
as: [IRM(1.2T)+IRM(-0.3T)]/2  and expressed in Am2/kg.
S:  (S Ratio) calculated as IRM(-0.3T)/IRM(1.2T).
Element concentration, Cr: Chromium-ppm
Element concentration, Cr:  Copper-ppm
Element concentration, Fe: Iron- Wt%
Element concentration, Mn: Manganese-ppm
Element concentration, Mo: Molybdenum-ppm
Element concentration, Nb: Niobium-ppm
Element concentration, Ni: Nickel-ppm
Element concentration, Rb: Rubidium-ppm
Element concentration, Sr: Strontium-ppm
Element concentration, Ti: Titanium-Wt %
Element concentration, V: Vanadium-ppm
Element concentration, Y: Yttrium-ppm
Element concentration, Zn: Zinc-ppm
Element concentration, Zr: Zirconium-ppm
Total Carbon:  Percent of carbon (both organic and inorganic) in
Carbonate Carbon:  Percent of inorganic carbon in sample.
Organic Carbon:  Percent of organic carbon in sample.  Calculated
as total carbon minus carbonate carbon.

U.S. Geological Survey Open-File Report 96-294