DOI: 10.5281/zenodo.14775362
title: Rock magnetic measurements of sediment from the Terrebonne Basin, Gulf of America (Gulf of Mexico), Walker Ridge Block 313, Site H, Expedition UT-GOM2-2

description: These data include magnetic susceptibility measured at high and low frequency, along with calculations of the frequency dependence of magnetic susceptibility, on discrete sediment samples collected from the Terrebonne Basin at UT-GOM2-2 Site H Holes H003 and H002. Magnetic susceptibility values can be a first order indicator of ferrimagnetic iron oxides and/or sulfides that can be used for interpreting the paleoenvironmental and diagenetic history of the sediments in sedimentary basins (Liu et al., 2012; Roberts, 2015; Verosub and Roberts, 1995). Magnetic susceptibility values can be a first order indicator of ferrimagnetic iron oxides and/or sulfides in the sediment.

The samples were collected from cores recovered during the UT-GOM2-2 expedition in August 2023 (Flemings et al., 2025a, https://doi.org/10.5281/zenodo.13970849). All samples were collected from split cores and whole round porewater squeeze cake sediments during post-expedition sampling operations in September 2023. Cores were collected on the D/V Q4000 using conventional (advanced piston coring and extended core barrel coring) and pressure coring (Pressure Coring Tool with Ball Valve). Conventional and depressurized pressure cores were then stored refrigerated until they were split and sampled in September 2023.

Samples for dual-frequency magnetic susceptibility measurements were collected in 8cm3 (2 x 2 x 2 cm) plastic paleomagnetic cubes (ASC Scientific) following IODP procedures (Richter et al., 2007). Samples were sampled immediately after core splitting and weighed in tared paleomagnetic cubes.  Each sample was measured that same day using a Bartington MS3 Magnetic Susceptibility Meter with a Bartington MS2B Dual-Frequency Magnetic Susceptibility Sensor following the steps set forth in the operating manual (Bartingon Instruments, 2022). Each sample was measured for low frequency (LF) magnetic susceptibility at 465 Hz with an air blank before and after the measurement. Each sample was measured for high frequency (HF) magnetic susceptibility at 4650 Hz with an air blank before and after the measurement. The LF and HF  values were normalized on a mass-basis using the instrument software. Frequency dependence of magnetic susceptibility was calculated in the instrument software using the formula of Dearing et al. (1996). After the magnetic susceptibility measurements, samples were stored frozen and vacuum-sealed for later additional rock magnetic analyses.  For a more detailed description of the methods see Expedition UT-GOM2-2 Methods: Rock Magnetism (Flemings et al., 2025b, https://doi.org/10.5281/zenodo.13971228).

Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

The attached readme file, previewed below, describes the data file in this dataset and its contents. The readme file also contains links to where the data is presented in the expedition proceedings.

Additional data you might expect to find in this dataset can instead be found at the following locations:

There are additional core logging measurements of magnetic susceptibility provided by Geotek, Inc. including MSCL-S measurements on whole round cores in College Station, TX; Magnetic susceptibility measurements on whole round cores in Salt Lake City, Utah; and MSCL-XZ measurements on the archival half of split cores in Salt Lake City, Utah. These data can be found in the MSCL-S Conventional Core Logs Data set https://doi.org/10.5281/zenodo.14518382, the MSCL-S Conventionalized Pressure Core Logs Date set http://doi.org/10.5281/zenodo.14518437, and the MSCL-XZ Split Core Logs Data set http://doi.org/10.5281/zenodo.14277995.

For additional information on sample collection, the UT-GOM2-2 Expedition sample log can be found in the Curation dataset (http://doi.org/10.5281/zenodo.14926309). Download file UT-GOM2-2 CORE LOG depths – sortable, see tab “Sample-measurement log” sample code “RMG” for background magnetic susceptibility and “ARM” for anomalies of magnetic susceptibility collected from split cores. See “IWO” and “IWR” for samples collected from pore water squeeze cake sediment.