The formation of continental margin strata

Metadata also available as - [Outline] - [Parseable text] - [XML]

Frequently-anticipated questions:

What does this data set describe?

Title: The formation of continental margin strata
Abstract:
" The strata formed on continental margins record the history of both marine and terrestrial events occurring on Earth. The STRATAFORM Program was created to develop a better understanding of relationships between these events and margin stratigraphy. In order to obtain the maximum information from strata, they are being examined simultaneously on various temporal and spatial scales, and their formation is being studied where events and accumulation are known to be active. The general objectives of STRATAFORM are: to add geological perspective to studies of sedimentary processes, to constrain stratigraphic interpretations better, and to develop numerical models relating processes and stratigraphy. This research is being undertaken on margins off northern California and New Jersey, which provide unique opportunities for investigation of short-term and long-term stratigraphy, respectively. This volume and paper focus upon studies undertaken off northern California, north of Cape Mendocino. This area is tectonically active, with a coastal mountain range, narrow shelf, and input of sediment primarily from the Eel River. Recent estimates indicate that 1 to 3×107 t/yr of mud (silt and clay) are supplied to the continental shelf. Sand accumulates on the inner shelf (<55 m water depth), and the mud rapidly deposits on the middle shelf north of the Eel mouth. An energetic physical regime causes significant seaward transport of muddy sediment, and much (>70%) reaches the continental slope (or deeper). During the previous lowstand of sea level, sediment discharge was ~25% greater, and probably led to hyperpycnal, debris and other flows transporting sediment down the slope. On the Eel shelf, flood and storm events combine to create normally stratified fine-grained layers with basal sand, and much terrestrial organic debris. These layers are modified through time, but some can be buried and preserved. Subsurface flood layers seem to impact observations of acoustic backscatter on the middle shelf, and subsurface fluids (gas? freshwater?) affect electromagnetic measurements on the inner shelf. Budgets of Eel River mud accumulation for the past century indicate ~20% trapped on the adjacent shelf and ~20% on the upper slope (150-600 m). The remaining 60% is dispersed to more distal locations. Over Holocene time scales, Eel River sediment has built a small sandy subaqueous delta, and a subtle bulge of muddy sediment on the middle shelf north of the river. Gullies have been eroded on the open slope during lowstands of sea level, and have accreted upward during highstands. A massive failure has formed the Humboldt slide, due to earthquake activity and unstable substrates (possibly from excess pore pressures and gas). The tectonic setting has impacted margin stratigraphy from small scales (fluid-expulsion pockmarks) to large scales (spatial variation of late Cenozoic sedimentation). The broad dispersal of Eel sediment demonstrates the three-dimensional character of the resulting stratigraphy, including the large-scale clinoform structure developed on the shelf/upper slope. The rollover point (topset/foreset boundary) for this feature is the shelf break (i.e., below sea level), which is important information for stratigraphic interpretations of sea-level change. "
Supplemental_Information:
Partially funded through the STRATAFORM Program within the Geology and Geophysics at the Office of Naval Research (J.H. Kravitz), ONR grant NOOO149510060. Data collected as part of the STRATAFORM project provided for inclusion into usSEABED by the originators (C. Alexander, J. Borgeld, C. Nittrouer) and may include pre-STRATAFORM data from the area.
  1. How should this data set be cited?

    Nittrouer, Charles, Alexander, Clark, and Borgeld, Jeffry, 1999, The formation of continental margin strata: Marine Geology Special Issue: The formation of continental-margin strata, C.A. Nittrouer, editor Volume 154 (1999) 1-426, Elsevier, Amsterdam.

    Other_Citation_Details: Special Issue ISSN 0025-3227

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -124.74500
    East_Bounding_Coordinate: -124.10765
    North_Bounding_Coordinate: 41.67180
    South_Bounding_Coordinate: 38.30628

  3. What does it look like?

    Strataform_Project (.jpg)
    Sample distribution with coastline and bathymetry for reference.

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 1979
    Ending_Date: 1999
    Currentness_Reference: Publication date

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: Paper

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • Entity point (563)

    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 0.0001. Longitudes are given to the nearest 0.0001. Latitude and longitude values are specified in Decimal degrees.

  7. How does the data set describe geographic features?

    Point
    SDTS point (Source: Source report)

    Sample number
    Sample number (Source: Unpublished data)

    Alpha numeric code based on cruise identification and sample number.

    Cruise ID
    Cruise identifier (Source: Unpublished data)

    ValueDefinition
    Cruise ID TT141Data collected aboard the R/V Tommy Thompson, 1979, provided by Jeff Borgeld
    Cruise ID W9502Data collected aboard the R/V Wecoma, 1995, provided by Clark Alexander
    Cruise ID W9509AData collected aboard the R/V Wecoma, 1995, provided by Jeff Borgeld and Charles Nittrouer
    Cruise ID PH950304Data collected aboard the R/V Pacific Hunter, 1995, provided by Charles Nittrouer
    Cruise ID PH950515Data collected aboard the R/V Pacific Hunter, 1995, provided by Charles Nittrouer
    Cruise ID PH951110Data collected aboard the R/V Pacific Hunter, 1995, provided by Charles Nittrouer
    Cruise ID PH951216Data collected aboard the R/V Pacific Hunter, 1995, provided by Charles Nittrouer
    Cruise ID WR961AData collected aboard the R/V Warrior, 1996, provided by Charles Nittrouer
    Cruise ID TN062Data collected aboard an unknown vessel, provided by Clark Alexander
    Cruise ID PH960317Data collected aboard the R/V Pacific Hunter, 1996, provided by Charles Nittrouer
    Cruise ID PH960424Data collected aboard the R/V Pacific Hunter, 1996, provided by Charles Nittrouer
    Cruise ID W9701AData collected aboard the R/V Wecoma, 1997, provided by Charles Nittrouer
    Cruise ID W9606AData collected aboard the R/V Wecoma, 1996, provided by Charles Nittrouer
    Cruise ID W9701AData collected aboard the R/V Wecoma, 1997, provided by Charles Nittrouer
    Cruise ID M9707Data collected aboard an unknown vessel, 1997, provided by Charles Nittrouer
    Cruise ID PS9705Data collected aboard the R/V Pt. Sur, 1997, provided by Charles Nittrouer
    Cruise ID W9801Data collected aboard the R/V Wecoma, 1998, provided by Charles Nittrouer
    Cruise ID W9807AData collected aboard the R/V Wecoma, 1998, provided by Jeff Borgeld
    Cruise ID PS9803Data collected aboard the R/V Pt. Sur, 1998, provided by Charles Nittrouer

    Gravel
    Amount of gravel in sample (Source: Unpublished data)

    Gravel was not measured

    Sample description
    Verbal description of sample (Source: Unpublished data)

    Core log and/or photos, including color

    Sand
    Amount of sand in sample (Source: Unpublished data)

    Range of values
    Minimum:0.46
    Maximum:96.06
    Units:Percent
    Resolution:0.01

    Silt
    Amount of silt in sample (Source: Unpublished data)

    Range of values
    Minimum:2.55
    Maximum:83.16
    Units:Percent
    Resolution:0.01

    Clay
    Amount of clay in sample (Source: Unpublished data)

    Range of values
    Minimum:0.13
    Maximum:59.82
    Units:Percent
    Resolution:0.01

    Median
    Median grain size value (Source: Unpublished data)

    Range of values
    Minimum:1.6
    Maximum:8.59
    Units:Phi
    Resolution:0.01

    Mean
    First moment of grain size distribution (Source: Unpublished data)

    Range of values
    Minimum:4.02
    Maximum:8.88
    Units:Phi
    Resolution:0.01

    Standard deviation (sorting)
    Second moment of grain size distribution (Source: Unpublished data)

    Range of values
    Minimum:2.16
    Maximum:3.65
    Units:Phi
    Resolution:0.01

    Skewness
    Third moment of grain size distribution (Source: Unpublished data)

    Range of values
    Minimum:-0.32
    Maximum:1.12
    Units:Unitless
    Resolution:0.01

    Kurtosis
    Fourth moment of grain size distribution (Source: Unpublished data)

    Range of values
    Minimum:-1.27
    Maximum:4.15
    Units:Unitless
    Resolution:0.01

    Inman mean
    Mean grainsize determined using Inman, 1952 equation (Source: Unpublished data)

    Range of values
    Minimum:1.66
    Maximum:8.71
    Units:Phi
    Resolution:0.01

    Inman standard deviation (sorting)
    Standard deviation of grainsize distribution using Inman, 1952 equation (Source: Unpublished data)

    Range of values
    Minimum:0.29
    Maximum:3.69
    Units:Phi
    Resolution:0.01

    Inman first skewness
    First skewness of grain size distribution using Inman, 1952 equation (Source: Unpublished data)

    Range of values
    Minimum:-0.27
    Maximum:0.92
    Units:Percent
    Resolution:0.01

    Inman Kurtosis
    Kurtosis of grain size distribution using Inman, 1952 equation (Source: Unpublished data)

    Range of values
    Minimum:0.11
    Maximum:4.82
    Units:Percent
    Resolution:0.01

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

    Charles Nittrouer at the University of Washington, Clark Alexander at the Skidway Institute of Oceanography and Jeffry Borgeld at Humboldt State University for the collection, analysis and archival of data. For inclusion into usSEABED: Digitization and formatting: K. Halimeda Kilbourne (USGS), Jane Reid (USGS), and Mark Zimmermann (NOAA). Formatting corrections: Jane Reid (USGS) and Chris Jenkins (University of Colorado).

  3. To whom should users address questions about the data?

    See cruise identification and distributors
    NA
    NA
    NA, NA NA

    See distributors (voice)
    See distributors

Why was the data set created?

"The STRATAFORM Program has three primary objectives. One is to use insights gained from observations of long-term (1000 to 100,000 yr) stratigraphic assemblages (i.e. sequence stratigraphy) to add geological perspective to studies of sedimentary processes. Another objective is touse these investigations of how short-term (<100 yr) sedimentary processes form strata, so better constraints can be placed on sequence-stratigraphic interpretations. The final objective is to employ modeling studies to bridge the gap between time scales of sedimentary processes and those of sequence stratigraphy; in this way, knowledge of processes and stratigraphy can be applied better for predictive and interpretative purposes."

How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    Date: Unknown (process 1 of 1)
    Processes varied by PI and lab; see Marine Geology Volume

    Data sources used in this process:

    • Unknown

    Data sources produced in this process:

    • STRATAFORM data

  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?

    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.

  2. How accurate are the geographic locations?

    Navigation by DGPS, usually good to +/- 5 meters.

  3. How accurate are the heights or depths?

    Depth determination method unknown; no assessment made for accuracy.

  4. Where are the gaps in the data? What is missing?

    All data are included; some data are decommissioned due to no sample/photo information (failed attempt?).

  5. How consistent are the relationships among the observations, including topology?

    Tests were performed on the textural class values to ensure completeness.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints:
None. Journal is available at libraries; many papers within the volume are available online.
Use_Constraints:
Cite Jeff Borgeld and the University of Washington as originators of the data.

  1. Who distributes the data set? (Distributor 1 of 3)

    Clark Alexander
    Skidway Institute of Oceanography
    10 Ocean Science Circle
    Savannah, GA 31411

    912-598-2329 (voice)
    912-598-2310 (FAX)
    clark@skio.peachnet.edu

  2. What's the catalog number I need to order this data set?

    Unpublished STRATAFORM data

  3. What legal disclaimers am I supposed to read?

    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.

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    None

  1. Who distributes the data set? (Distributor 2 of 3)

    Jeff Borgeld
    Humboldt State University
    Department of Oceanography
    Arcata, CA 95521-8299

    707-826-3328 (voice)
    707-826-4145 (FAX)
    jdb2@humboldt.edu

  2. What's the catalog number I need to order this data set?

    Unpublished STRATAFORM data

  3. What legal disclaimers am I supposed to read?

    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.

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    None

  1. Who distributes the data set? (Distributor 3 of 3)

    Charles Nittrouer
    University of Washington
    Box 351310
    Seattle, WA 98195

    206-543-5099 (voice)
    206-543-0489 (FAX)
    nittrouer@ess.washington.edu

  2. What's the catalog number I need to order this data set?

    Unpublished STRATAFORM data

  3. What legal disclaimers am I supposed to read?

    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.

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    None

Who wrote the metadata?

Dates:
Last modified: 2005
Metadata author:
U.S. Geological Survey
c/o Jane A. Reid
Geologist
400 Natural Bridges Drive
Santa Cruz, CA 95060

831-427-4727 (voice)
jareid@usgs.gov

Contact_Instructions: Email preferred
Metadata standard:
CSDGM Version 2 (FGDC-STD-001-1998)

Generated by mp version 2.8.17 on Sat May 20 20:55:54 2006