Sediment Magnetic and Paleomagnetic Data from Buck Lake, Oregon

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What does this data set describe?

Title: Sediment Magnetic and Paleomagnetic Data from Buck Lake, Oregon
Abstract:
Sediment magnetic, paleomagnetic and geochemical results have been obtained from lacustrine sediments recovered in a 30-meter core taken by rotary drilling methods at Grass Lake, Siskiyou County, California. The data have been analyzed and interpreted in terms of environmental change in the Grass Lake catchment over the past ca. 100,000 years.
  1. How might this data set be cited?
    Best, Patti J., Reynolds, Richard L., Rosenbaum, Joseph G., Drexler, John, and Adam, David. P., 1996, Sediment Magnetic and Paleomagnetic Data from Buck Lake, Oregon: U.S. Geological Survey Open-File Report 96-294, U.S. Geological Survey, Denver Colorado.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -122.166
    East_Bounding_Coordinate: -122.166
    North_Bounding_Coordinate: 41.75
    South_Bounding_Coordinate: 41.75
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: Quaternary
    Currentness_Reference:
    publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: model
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.05. Longitudes are given to the nearest 0.05. Latitude and longitude values are specified in Decimal degrees.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Resolution: 5
      Altitude_Distance_Units: feet
      Altitude_Encoding_Method: Attribute values
      Altitude_Datum_Name: North American Vertical Datum of 1988
      Depth_System_Definition:
      Depth_Datum_Name: Local surface
      Depth_Resolution: .01
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:

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

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Patti J. Best
    • Richard L. Reynolds
    • Joseph G. Rosenbaum
    • John Drexler
    • David. P. Adam
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Richard L. Reynolds
    U.S. Geological Survey
    Geologist
    Box 25046, Denver Federal Center,
    Denver, Colorado
    United States of America

    (303) 236-1303 (voice)
    rreynolds@usgs.gov

Why was the data set created?

The magnetic and geochemical results will be compared to detailed pollen analysis to test the possibility that variations in the magnetic mineralogy are related to paleoclimatic change and associated watershed processes. This report also describes the methods used to obtain the magnetic and geochemical results.

How was the data set created?

  1. From what previous works were the data drawn?
    Adam and others (1994) (source 1 of 2)
    Adam, D.P., Rieck, H.J., McGann, M.L., Schiller, K., and Sarna-Wojcicki, A.M., 1994, Lithologic description of sediment cores from Grass Lake, Siskiyou County, California U.S. Geological Survey Open-file Report No. 94-651, 36pp.: U.S. Geological Survey Open-File Report 94-651, U.S. Geological Survey, Menlo Park, California.

    Type_of_Source_Media: paper
    Source_Contribution: site description, drilling methods, lithology of sediments
    Best, 1996 (source 2 of 2)
    Best, P.J., 1996, Environmental controls on magnetic mineralogy and geochemistry of late Quaternary lacustrine sediments from Grass Lake and Tule Lake, northern California: M.S. Thesis, 139 p.: Masters of Science Thesis none, University of Colorado, Boulder, Boulder Colorado.

    Type_of_Source_Media: paper
    Source_Contribution: background study
  2. How were the data generated, processed, and modified?
    Date: Unknown (process 1 of 7)
    Sampling
    Paleomagnetic specimens, 3.2 cm3 in volume, were taken in plastic boxes. Pedestals were cut in the core, boxes were placed over the pedestals, and the sediment in the boxes was then cut from the core and the boxes were sealed. Orientation was maintained with respect to the core axis but the specimens were not azimuthally oriented. Each paleomagnetic specimen was given a unique box number and the depth interval (with respect to the top of the core segment) covered by each box was recorded. Subsequently each specimen was assigned a second unique number, the sample number. These boxed samples were used for measurements of magnetic susceptibility, paleomagnetic directions and magnitudes, laboratory induced magnetizations, and hysteresis properties.
    Date: Unknown (process 2 of 7)
    Paleomagnetic Directions
    Natural Remanent Magnetization (NRM) was measured on oriented samples using a 90-Hz spinner magnetometer with a sensitivity better than 10-5 A/m. Samples were demagnetized in steps through alternating-field (AF) demagnetization with peak fields of 5, 10, 15, 20, 30, 40, 60 and 80 milliTeslas (mT). Declination and inclination were calculated from a best fit line of the demagnetization data displayed as orthogonal vector diagrams.
    Date: Unknown (process 3 of 7)
    Magnetic Susceptibility
    Volume susceptibility (MS) was measured using a susceptometer with a sensitivity better than 10-5 volume SI. Samples were measured in a 0.1 mT induction at a low frequency of 600 Hz ( MSlf) and high frequency of 6000 Hz (MShf). For each sample, the MS value was determined as the mean of four measurements. Frequency dependent susceptibility was calculated as: FDMS=(MSlf-MShf)/MSlf.
    Date: Unknown (process 4 of 7)
    Laboratory induced magnetization
    After the paleomagnetic analysis, anhysteretic remanent magnetization (ARM) and isothermal remanent magnetization (IRM) experiments, magnetizationswere measured with a high speed spinner magnetometer. ARM was imparted in a decreasing AF from a peak induction of 100 mT and a DC bias of 0.1 mT IRM magnetizations were generated at room temperature using an impulse magnetizer. First IRM was imparted in a 1.2T induction ( IRM1.2T). The samples were then magnetized in the opposite direction using an induction of 0.3T (IRM-0.3T). Hard isothermal remanent magnetization (HIRM) and the S-parameter were calculated as follows: HIRM=(IRM1.2T+IRM-0.3T)/2 S=IRM-0.3T/IRM1.2T
    Date: Unknown (process 5 of 7)
    Elemental Abundance
    Elemental abundances were determined on selected samples using energy dispersive X-ray fluorescence analysis at the University of Colorado's Department of Geological Sciences. Contents of Cr, Cu, Fe, Mn, Mo, Nb, Ni, Rb, Sr, Ti, V, Y, Zn and Zr were measured.
    Date: Unknown (process 6 of 7)
    Determination of carbon content
    Organic carbon was determined on selected samples as the difference between total and inorganic carbon. Sample splits were combusted in oxygen for 5 minutes at 960oC. Total CO2 was measured using a coulometer. Inorganic carbon was then determined through acidification with perchloric acid and measured with a coulometer.
    Date: 22-Aug-1997 (process 7 of 7)
    Creation of original metadata record Person who carried out this activity:
    Kevin M. Foley
    U.S. Geological Survey
    Physical Scientist
    U.S. Geological Survey
    Reston, Virginia
    USA

    (703) 648-5285 (voice)
    (703) 648-6560 (FAX)
    kfoley@usgs.gov
  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    Sampling:
    Samples used for paleomagnetic directions, magnetic susceptibility, and laboratory induced magnetizations were taken approximately every 5 cm. The majority of the core was soft, and a cube with a volume of 3.2 cm3 oriented with respect to the top of the core could be inserted directly into the sediment.
    Approximately every 100 cm, a 10 to 20 cm interval of sediment was collected and stored in bags for magnetic mineral separations.
    Paleomagnetic directions:
    Natural Remanent Magnetization (NRM) was measured on oriented samples using a 90-Hz spinner magnetometer with a sensitivity better than 10-5 A/m. Samples were demagnetized in steps through alternating-field (AF) demagnetization with peak fields of 5, 10, 15, 20, 30, 40, 60 and 80 milliTeslas (mT).
    Laboratory induced magnetization:
    Magnetizations were measured with a high speed spinner magnetometer. ARM was imparted in a decreasing AF from a peak induction of 100 mT and a DC bias of 0.1 mT. IRM magnetizations were generated at room temperature using an impulse magnetizer. First IRM was imparted in a 1.2T induction (IRM1.2T). The samples were then magnetized in the opposite direction using an induction of 0.3T (IRM-0.3T).
    Elemental Abundance:
    Elemental abundances were determined on selected samples using energy dispersive X-ray fluorescence analysis.
    Organic carbon was determined on selected samples as the difference between total and inorganic carbon. Sample splits were combusted in oxygen for 5 minutes at 960oC. Total CO2 was measured using Total CO2 was measured using a coulometer. Inorganic carbon was then determined through acidification with perchloric acid and measured with a coulometer.
  2. How accurate are the geographic locations?
    The horizontal coordinates of the Grass Lake core site were determined from the position of the site on a 7.5 minute topo quad map The accuracy of the measurements are estimated to be + or - 0.005 degrees latitude and + or - 0.005 degrees longitude.
  3. How accurate are the heights or depths?
    The altitude of the core sight was determined from a 7.5 minute topographic quadrangle map.
  4. Where are the gaps in the data? What is missing?

    A total of 542 samples were collected
    82 samples, labeled "Vial" samples were collected for analysis of elemental concentrations and carbon content.
    458 samples, labeled with "Box no." were collected in 3.2 cc cubes for magnetic mineral studies
    "Sample Density (kg/m3)" is recorder for all "box" samples
    Declination, Inclination, NRM are recorded for 412 "box" samples.
    Data are not recorded for 24 samples that were the core was disturbed prior to sampling.
    Data are not recorded for 8 samples due to "poor fit" indicating that the vector diagram was extremely poor and paleomagnetic directions were not calculated.
    Data are not recorded for 15 samples labeled "not used". The data from these samples was not recorded due to displacement of sediment during magnetometer measurement.
    Sediment magnetic data are recorded for 457 of 458 "box" samples
    Elemental abundance data were recorded for 82 samples
    Carbon contents data are recordeded for 25 samples.
  5. How consistent are the relationships among the observations, including topology?

    Five tables record information from the various studies performed on core material. All studies were not completed on all samples. Two different sample entities were collected from core material, "Vials" and "Sample boxes". "Vials" and "Sample boxes" were labeled as follows:
    Paleomagnetic specimens, 3.2 cm3 in volume, were taken in plastic boxes. Each paleomagnetic specimen was given a unique box number and the depth interval (with respect to the top of the core segment) covered by each box was recorded. Subsequently each specimen was assigned a second unique number, the sample number. Core material removed from around each paleomagnetic specimen was placed in one or more numbered vials. The depth interval contained in each vial corresponds closely (but not exactly) to the interval sampled by a paleomagnetic specimen. These vials were later assigned sample numbers. Material in these vials was used to determine grain size, and elemental concentrations.
    "sample depth (m)" is consistantly used throughout the data tables. Other entities are used as follows.
    +-------------------+--------------------------------------------+ | | Table Table Table Table Table | | | 1 2 3 4 5 | +-------------------+--------------------------------------------+ | Sample number | X X | | | | | Sample box number |X some X X X | | | | | Vial number |X some X X | +-------------------+--------------------------------------------+

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: none
Use_Constraints: none
  1. Who distributes the data set? (Distributor 1 of 1)
    Peter N Schweitzer
    USGS Midwest Area
    Geologist
    Mail Stop 954
    12201 Sunrise Valley Dr
    Reston, VA
    USA

    703-648-6533 (voice)
    703-648-6252 (FAX)
    pschweitzer@usgs.gov
  2. What's the catalog number I need to order this data set? USGS OFR 96-294
  3. What legal disclaimers am I supposed to read?
    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.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 05-Feb-2016
Metadata author:
Peter N Schweitzer
USGS Midwest Area
Collection manager, USGS Geoscience Data Clearinghouse, http://geo-nsdi.er.usgs.gov/
Mail Stop 954
12201 Sunrise Valley Dr
Reston, VA
USA

703-648-6533 (voice)
703-648-6252 (FAX)
pschweitzer@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://geo-nsdi.er.usgs.gov/metadata/open-file/96-294/metadata.faq.html>
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