Arnold, T Elliott (2026): Hydrogen isotopes of n-alkane biomarkers and brGDGT temperatures from Lake Tulane, Florida, USA [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.989435

This dataset includes temperatures derived from branched glycerol dialkyl glycerol tetraethers (brGDGTs) and regional hydrology changes reconstructed from hydrogen isotope ratios (δ2H) of n-alkanes extracted from a lacustrine sediment core from Lake Tulane, Florida, USA. In 1994, 8 cores from 6 locations (2 complete overlaps) were acquired from a transect along the north basin of Lake Tulane. Cores were taken with a 7.5-cm diameter Wright square-rod piston corer from an anchored raft. Separately, a single surface-water interface core was acquired from the north basin of Lake Tulane in 2010. brGDGTs and n-alkanes were extracted from archived core sections at 8-10 cm intervals in August of 2018 and from the surface-water interface core at 5 cm intervals in August of 2019. The archived core interval spanned Heinrich Stadials 4-2 (41,000-17,000 BP) and the surface-water interface core spanned 78-0 BP. brGDGT distributions from both cores were measured via atmospheric pressure chemical ionization high-performance liquid chromatography-mass spectrometry (APCI/HPLC–MS), and hydrogen isotope ratios of n-alkanes were measured on a Thermo Trace GC Ultra coupled to a Thermo Electron Delta V Advantage IRMS with an Isolink combustion furnace. The brGDGT data was converted to degrees Celsius (°C) following the open-sourced code provided in O'Beirne et al. (2023, doi:10.1016/j.gca.2023.08.019). Hydrogen isotope results are given in the conventional δ-notation. A proxy for seasonal precipitation and aridity (ε(C29-C23)) was created, which reflects the difference between the δ2H values of aquatic n-alkanes (δ2HC23) and terrestrial leaf wax δ2H values (δ2HC29) using the following equations: (1) α = (1000 + 𝛿2HC29)/(1000 + 𝛿2HC23), and (2) ε(C29-C23) = (α -1) x 1000.