We present data used as part of an integrative early diagenesis study (submitted September 2022 to Marine Geology) focused on identifying zones of magnetite dissolution and pyrite precipitation in which magnetic susceptibility records are altered in gas-hydrate bearing sediments on the Cascadia Margin using archived cores from the Ocean Drilling Program (ODP) and Integrated Ocean Drilling Program (IODP). We analyzed the upper 85 to 100 m below seafloor (mbsf) from ODP Sites 1249 and 1252, and IODP Site U1325. ODP 1249 is at the summit of Hydrate Ridge in an area of active methane seepage and massive gas hydrate accumulations and ODP 1252 is in a nearby slope basin with little occurrence of hydrate. IODP Site U1325 is on the northern Cascadia Margin in a slope basin, with turbidite-hosted gas hydrate. We also include XRF data from the upper sections of ODP Site 1251, IODP U1327, and U1328. We measured X-ray fluorescence using an Avaatech core scanner at the IODP Gulf Coast Repository at Texas A&M University. We measured total carbon, total organic carbon (TOC), total nitrogen, and total sulfur using a Perkin Elmer 2400 Series CHNS/O Analyzer at the university of New Hampshire (ODP Site 1249 and 1252 only). A subset was analyzed for δ¹³C-TOC using a Costech ECS 4010 elemental analyzer interfaced with a Thermo Finnegan Delta Plus XP continuous flow isotope ratio mass spectrometer at Washington State University. Grain size was measured with a Malvern Mastersizer 2000 laser diffraction particle size analyzer and Hydro 2000G dispersal unit at the University of New Hampshire. Mass frequency-dependent magnetic susceptibility was measured using a Bartington MS2 Magnetic Susceptibility Meter and Bartington MS2B dual frequency sensor (Site U1325 only). Isothermal remanent magnetization and thermal demagnetization curves were measured using a HSM2 SQUID-based Spinner Magnetometer with an ASC Scientific IM-10-30 Impulse Magnetizer and ASC Scientific TD-48SC magnetically-shielded oven (Site U1325 only). Radiocarbon was measured on mixed planktic foraminifers at the Radiocarbon was measured at National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility at Woods Hole Oceanographic Institution (ODP Site 1252 and IODP Site U1325).. Radiocarbon ages were calibrated to calendar ages using CALIB 8.2 and the Marine20 calibration curve. For ODP Site 1252 we used a reservoir correction of 230 ± 50 years (Yaquina Bay, Oregon, USA) and for IODP Site U1325 we used a reservoir correction of 202 ± 50 years (Amphitrite Point, British Columbia, Canada). δ¹⁸O was measured on benthic foraminifer Uvigerina peregrina tests using a Finnegan MAT 252 isotope ratio mass spectrometer with Kiel III device at the Oregon State University Stable Isotope Laboratory (ODP 1252) and a Finnegan MAT 253 isotope ratio mass spectrometer with Kiel IV device at the University of Michigan Stable Isotope Laboratory (ODP Site 1249 and IODP Site U1325).

We present data used as part of an integrative early diagenesis study (submitted September 2022 to Marine Geology) focused on identifying zones of magnetite dissolution and pyrite precipitation in which magnetic susceptibility records are altered in gas-hydrate bearing sediments on the Cascadia Margin using archived cores from the Ocean Drilling Program (ODP) and Integrated Ocean Drilling Program (IODP). We analyzed the upper 85 to 100 m below seafloor (mbsf) from ODP Sites 1249 and 1252, and IODP Site U1325. ODP 1249 is at the summit of Hydrate Ridge in an area of active methane seepage and massive gas hydrate accumulations and ODP 1252 is in a nearby slope basin with little occurrence of hydrate. IODP Site U1325 is on the northern Cascadia Margin in a slope basin, with turbidite-hosted gas hydrate. We also include XRF data from the upper sections of ODP Site 1251, IODP U1327, and U1328. We measured X-ray fluorescence using an Avaatech core scanner at the IODP Gulf Coast Repository at Texas A&M University. We measured total carbon, total organic carbon (TOC), total nitrogen, and total sulfur using a Perkin Elmer 2400 Series CHNS/O Analyzer at the university of New Hampshire (ODP Site 1249 and 1252 only). A subset was analyzed for δ¹³C-TOC using a Costech ECS 4010 elemental analyzer interfaced with a Thermo Finnegan Delta Plus XP continuous flow isotope ratio mass spectrometer at Washington State University. Grain size was measured with a Malvern Mastersizer 2000 laser diffraction particle size analyzer and Hydro 2000G dispersal unit at the University of New Hampshire. Mass frequency-dependent magnetic susceptibility was measured using a Bartington MS2 Magnetic Susceptibility Meter and Bartington MS2B dual frequency sensor (Site U1325 only). Isothermal remanent magnetization and thermal demagnetization curves were measured using a HSM2 SQUID-based Spinner Magnetometer with an ASC Scientific IM-10-30 Impulse Magnetizer and ASC Scientific TD-48SC magnetically-shielded oven (Site U1325 only). Radiocarbon was measured on mixed planktic foraminifers at the Radiocarbon was measured at National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility at Woods Hole Oceanographic Institution (ODP Site 1252 and IODP Site U1325).. Radiocarbon ages were calibrated to calendar ages using CALIB 8.2 and the Marine20 calibration curve. For ODP Site 1252 we used a reservoir correction of 230 ± 50 years (Yaquina Bay, Oregon, USA) and for IODP Site U1325 we used a reservoir correction of 202 ± 50 years (Amphitrite Point, British Columbia, Canada). δ¹⁸O was measured on benthic foraminifer Uvigerina peregrina tests using a Finnegan MAT 252 isotope ratio mass spectrometer with Kiel III device at the Oregon State University Stable Isotope Laboratory (ODP 1252) and a Finnegan MAT 253 isotope ratio mass spectrometer with Kiel IV device at the University of Michigan Stable Isotope Laboratory (ODP Site 1249 and IODP Site U1325).

Affine and splice files created for stratigraphic correlation.

Affine and splice files created for stratigraphic correlation.

We report on geochemical data from anoxic sequences of the Nicobar Fan, recovered during International Ocean Discovery Program (IODP) expedition 362 to the Sumatra subduction zone. Analyses include strontium and carbon isotope composition of pore fluids, elemental and isotopic composition of carbonate concretions, and whole sediment analyses.

Data related to collaborative study of fluid rock interaction in the Nicobar Fan sampled at Sites 1480 and 1481 during IODP Expedition 362 off Sumatra

Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.

Logging data are measurements of physical properties of the formation surrounding a borehole, acquired in situ after completion of coring (wireline logging) or during drilling (Logging-While-Drilling, LWD). The range of data (resistivity, gamma radiation, velocity, density, borehole images,…) in any hole depends on the scientific objectives and operational constraints.

No description available

Gas composition in the headspace gas was measured by an Agilent 7890A gas chromatograph with flame ionization detector in the KIGAM. The carbon isotopic ratios of CH4 and carbon dioxide (CO2) in eadspace gases were analyzed using a compound-specific isotope ratio-monitoring gas chromatograph/mass spectrometer at Isotech Laboratories Inc., USA.