|Description||This digital map database, compiled from previously published and unpublished data, and new mapping by the authors, represents the general distribution of bedrock and surficial deposits in San Mateo County.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|
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 centimeters. Sample depth within drive (m): Midpoint of depth interval in meters. 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 sample. 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