Thirumalai, Kaustubh; Richey, Julie N; Quinn, Terrence Michael (2021): Northwestern Gulf of Mexico Holocene G. ruber geochemistry from 2010-GB2-GC1 [dataset bundled publication]. PANGAEA, https://doi.org/10.1594/PANGAEA.935987

This dataset contains stable oxygen isotope, radiocarbon, and magnesium-to-calcium ratios measured in G. ruber (white) from a core in the northwestern Gulf of Mexico (Garrison Basin). The dataset also contains the inverted temperature, δ¹⁸O-sw (ice-volume corrected), and salinity values using the PSU Solver Algorithm. A Holocene composite of these parameters is provided for the Garrison Basin with higher-resolution (and previously published) late Holocene records from multi-cores. Here is the abstract from the paper: The Gulf of Mexico (GoM) is an integral component of oceanic circulation in the North Atlantic and helps facilitate poleward heat transport in the Western Hemisphere. Regionally, it serves as a key source of moisture for much of North America. Modern patterns of sea-surface temperature (SST) and salinity in the GoM are influenced by the Loop Current, its eddy-shedding dynamics, and the ensuing interplay with coastal processes. Here we present sub-centennial-scale records of SST and the stable oxygen isotope composition of seawater (δ¹⁸Osw; a proxy for changes in salinity) over the past 11,700 years using planktic foraminiferal geochemistry in sediments from the Garrison Basin, northwestern GoM. We measured δ¹⁸O and magnesium-to-calcium ratios in tests of Globigerinoides ruber (white variety) to generate quantitative estimates of past sea-surface conditions. Our results replicate and extend late Holocene reconstructions from the Garrison Basin, which we then use to create Holocene composites of SST and δ¹⁸Osw. We find considerable centennial and millennial-scale variability in both SST and δ¹⁸Osw, although their evolution over the Holocene is distinct. Whereas mean-annual SSTs display pronounced millennial-scale variability, δ¹⁸Osw exhibits a secular trend spanning multiple millennia and indicates increasing sea-surface salinity in the northwestern GoM since the early Holocene. We then synthesize available Holocene records from across the GoM, and alongside the Garrison Basin composite, uncover substantial, yet regionally consistent, spatiotemporal variability. Finally, we discuss the role of the Loop Current and coastal influx of freshwater in imposing these heterogeneities and conclude that dynamic and variable surface-ocean changes occurred across the GoM over the Holocene.