Abstract:

This dataset contains sediment texture and composition data collected aboard R/V Point Sur cruise PS18-25 in the northern Gulf of Mexico from 2018-05-18 to 2018-05-23. Three sites were sampled using a multi-corer between 1703 and 2381 m water depth. Sediment texture and composition data are generated for selected core sub-samples at 2mm sampling intervals for “surficial unit” and 5mm sampling resolution intervals to the base of cores. Sediment texture values are expressed as % Gravel, % Sand, % Silt and % Clay as calculated by dry weight (g), % Mud is calculated by combining % Silt and % Clay. Sediment composition is expressed as % TOM (Total Organic Matter) measured by Loss on Ignition (LOI), % Carbonate content measured by acid leaching, and the % Insoluble Residue (IR), which is likely dominated by terrigenous clastic (land-derived) sediment sources.

Suggested Citation:

Brooks, Gregg R. and Rebekka A. Larson. 2021. Sediment texture and composition data collected aboard R/V Point Sur cruise PS18-25 in the northern Gulf of Mexico from 2018-05-18 to 2018-05-23. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/C10E585R

Purpose:

Determine if/how sediment texture and composition varies in sediment cores as an indicator of sediment sources and depositional mechanisms.

Data Parameters and Units:

Cruise documentation was provided for the R/V Point Sur cruise PS18-25, led by chief scientist Dr. Arne Diercks. Sediment core collection latitude and longitude (decimal degrees), water depth of core site in meters (m), core collection date (MM/DD/YYYY), site identification (ID), core identification (ID), top depth of interval in millimeters (mm), bottom depth of interval in millimeters (mm), average depth of interval millimeters (average of top and bottom depths, mm), percent gravel (by dry weight), percent sand (by dry weight), percent silt (by dry weight), percent clay (by dry weight), percent mud (calculated by adding percent silt and clay, by dry weight), percent carbonate (by dry weight), percent Total Organic Matter (TOM) by Loss on Ignition (LOI) (by dry weight), percent Insoluble Residue (non-organic; by dry weight), laboratory/facility where the analysis was performed (Eckerd College, St. Petersburg Florida). Please note - blank cell denotes analysis not performed for the interval, and no data was generated.

Methods:

Sediment texture and composition analyses were conducted on extruded samples and included grain size, and calcium carbonate content (%CaCO3). Grain size was determined by wet sieving the sample through a 63µm screen. The fine-size (<63 µm) fraction was analyzed by pipette (Folk, 1965) to measure the relative percentage of silt (%silt) and clay (%clay). The sand-size (>63 µm) fraction was volumetrically too small to analyze further and is reported here as % sand. Carbonate content was determined by the acid leaching method according to Milliman (1974). Where there was not sufficient sediment from an interval for both sediment texture and composition, only sediment texture was performed.

Provenance and Historical References:

Folk, R. L., 1965. Petrology of Sedimentary Rocks, Hemphillis, Austin, Texas. Milliman, J. D., 1974. Marine Carbonates (2nd ed.): Berlin-Heidelberg New York (Springer-Verlag).

Individual Files: