Description: We present datasets associated with an approach to disentangle detrital and diagenetic influences on magnetic susceptibility in marine sediments in the Bay of Bengal. The goal of the approach is to identify zones in which titanomagnetite has been subject to dissolution and resulting in pyrite precipitation at paleo depths of the sulfate-methane transition zone (SMTZ) or paleo-seep activity. These data are from two sites with cores recovered during the Indian National Gas Hydrate Program Expedition 01 (NGHP-01). We characterize the upper 27 meters below seafloor (mbsf) at Hole NGHP-01-10D (15° 51.8609'N, 81° 50.0749' E, 1035 m water depth) and the upper 73 mbsf at Hole NGHP-01-16A (16° 35.5986' N, 082° 41.0070' E, 1252 m water depth). These sediments were collected using piston coring and extended core barrel coring during drilling on the JOIDES Resolution in June and July of 2006. We present high-resolution measurements of magnetic susceptibility (onboard Geotek multi-sensor core logging) and X-ray fluorescence (Cox Analytical core scanner at Woods Hole Oceanographic Institution, WHOI) for the elements Zr, Rb, Fe, Ti, Ca, and K. Discrete measurements of total organic carbon (TOC) and total sulfur (TS) were measured on powdered sediment samples using a Perkin Elmer CHNS/O 2400 Series II elemental analyzer at the University of New Hampshire (UNH). Grain size was measured using a Beckman Coulter LS 13320 Laser Diffraction Particle Size Analyzer at WHOI. We also present acquisition curves of isothermal remanent magnetization (IRM) from 0 to 1.1T and thermal demagnetization (20 to 580 degrees C) measured across three axes using an HSM2 SQUID spinner magnetometer at UNH. Authigenic carbonate nodules at Site 16 were pulverized and measured by X-ray diffraction at UNH to determine mineralogy. These carbonate powders at Site 16 were analyzed for oxygen and carbon isotopic signature using a Finnegan MAT 253 mass spectrometer with a Kiel IV carbonate preparation device (phosphoric acid at 77 °C) at the University of Michigan. Carbonate powders from Site 10 were analyzed by Finnegan MAT 252 mass spectrometer with a Kiel III carbonate preparation device (phosphoric acid at 70 °C) at Oregon State University (OSU) for oxygen and carbon isotopic signature. We picked mixed planktonic foraminifers (primarily Globigerinoides ruber and Globigerinoides sacculifer) from Site 16 sent them for radiocarbon analysis at National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility at WHOI. The radiocarbon ages were then calibrated using Calib 8.2 and the Marine20 calibration curve. We also picked benthic foraminifers from Site 16 (Hoeglundina elegans and Uvigerina peregrina) for analysis of oxygen and carbon isotopes at the University of Michigan.

Description: The dataset contains 500-2000 MHz brightness temperature measurements gathered by the Ultra-Wideband Software Defined Microwave Radiometer (UWBRAD) during the Ice Sheet and Sea Ice Airborne Microwave eXperiment (ISSIUMAX) in Terra Nova Bay, Antarctica. UWBRAD was operated from a DHC-6 Twin Otter during the XXXVIII Italian Antarctic Expedition. The campaign collected the first ultrawideband brightness temperature measurements in Antarctica over different targets including sea ice, ice sheets, glaciers, ice shelves, and land. The dataset was collected on 24-25 November 2018 in the coastal region surrounding Mario Zucchelli Station (-74.694807°, 164.113268°). The UWBRAD microwave radiometer measures nadiral circularly polarized brightness temperatures over the entire 500–2000 MHz range using multiple frequency channels. Since this frequency range is not a protected portion of the spectrum, the measurements can be affected by anthropogenic RFI. To address this issue, UWBRAD includes RFI detection and filtering methods to filter out artificial signals received by the radiometer. A full description of the instrument can be found in Andrews et al, 2022 (DOI: 10.1109/TGRS.2021.3090945). The published dataset is in ascii format and consists of geolocated nadiral brightness temperature measurements collected over 12 sub-bands whose central frequencies are 560, 660, 820, 900, 1180, 1240, 1370, 1500, 1630, 1740, 1860, and 1950 MHz. Only measurements with a viewing angle within 5 deg with respect to nadir are reported.

Description: Permeability, electrical resistivity, and thermal conductivity measurements were performed on samples from the Bent Hill area of the Middle Valley on the northern Juan de Fuca Ridge. Thermal conductivity measurements were also made on samples from the Trans-Atlantic Geotraverse (TAG) hydrothermal area in the Mid-Atlantic Ridge for direct comparison with previous studies and the Middle Valley results. Electrical resistivity and permeability measurements were made as a function of confining pressure on 15 samples comprising different lithologic compositions found in the Bent Hill area. The effect of pressure on electrical resistivity values is relatively small and the observed frequency dependence is highly controlled by the sulfide content in these rocks. Permeabilities are in the 10**-16 to 10**-20 m**2 (0.1-100 µD) range. Although permeability does not recover in samples that undergo significant permanent deformation, the elastic permeability dependence on confining pressure is relatively small. Permeability correlates with porosity. Permeability anisotropy correlates with the presence of oriented sulfide veins with increased flow parallel to the veins. Thermal conductivity measurements made on 41 samples from Middle Valley and 9 samples from the TAG area show systematic variations due to changes in composition and a weak relationship with porosity for sedimentary samples from Middle Valley. A comparison between the divided-bar and the half-space needle-probe methods of measuring thermal conductivity shows good agreement for the Leg 169 measurements unlike previous results from Legs 139 and 158. The discrepancies observed in earlier studies seem to be related to the long times used in the older measurements for the optimal T vs. ln(t) data interval. The apparatus used during Leg 169 was smaller, sampled a smaller volume of core, and in high conductivity material was not influenced by boundary effects.