This dataset contains the gas composition and isotope data from void, hydrate dissociation, and quantitative degassing samples. Void gases were extracted using a stainless-steel puncture sampler that was pushed through the core liner shortly after the core was collected onboard the Helix Q4000. Where solid hydrate or hydrate-bearing sediment was encountered in cryogenically frozen and depressurized samples, dissociated gas was then transferred to a Cali-5 Bond gas bag. Syringes and gas bag samples were collected from the top of the bubbling chamber of the quantitative degassing apparatus. Samples were analyzed for gas composition (C1-C5 hydrocarbons, CO2, O2, and N2) and methane δ13C isotopes at the U.S. Geological Survey Woods Hole Coastal and Marine Science Center using the Automated Sample Introduction Module (Auto-SIM) Gas Chromatography/Cavity Ring-Down Spectroscopy System (Auto-SIM GC/CRDS). See Expedition UT-GOM2-2 Methods: Gas Geochemistry (Flemings et al., 2025a, 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: The sample depths can be found in the curation dataset (http://doi.org/10.5281/zenodo.14926309). Download the file UT-GOM2-2 CORE LOG depths – sortable.xlsx. See tab “Sample-measurement log” sample code “VG” for void gas samples. See tab “Section-piece log” core processing code “QD” for quantitative degassing gas samples (also see the quantitative degassing dataset: https://doi.org/10.5281/zenodo.14775236). See tab “Section-piece log” sample code “CRYO, HYD” for dissociated gas from hydrate samples. Gas composition of headspace gas samples can be found in the Headspace Gas Geochemistry dataset (https://doi.org/10.5281/zenodo.14518633). Gas composition of additional void samples using an Inficon Fusion MicroGC chromatograph can be found in the void gas geochemistry dataset (https://doi.org/10.5281/zenodo.16689630).