Datasets generated for O'Mara et al. (2025), Capturing vegetation gradients along the West African margin using terrestrial plant biomarkers in marine sediments. Geochemistry, Geophysics, Geosystems.

Organic and inorganic geochemical data from a transect of marine core top sediments spanning the Iberian through West African margins in the North/South Atlantic Ocean (39.9°N–33.9°S). Core samples were provided by the Lmaont-Doherty Core Repository of Columbia University. Core information can be found in Table S1 in this dataset. Geochemical measurements include plant wax n-alkane concentration, mass accumulation rates, and carbon isotope values; pentacyclic triterpene methyl ethers (PTME) concentration and mass accumulation rates; U/Th series isotope measurements and estimated 230Thxs-derived mass accumulation rates. Plant-wax concentrations were made via gas chromatography-mass spectrometry at the Lamont-Doherty Earth Observatory (LDEO) Organic Geochemistry Lab using an Agilent 7890A GC coupled to an Agilent 5975C MS, plant-wax isotope measurements were made at the LDEO Stable Isotope Lab using A Thermo Delta V Advantage isotope ratio mass spectrometer coupled to a Thermo Trace GC Ultra and Isolink through a ConFlo IV, U/Th measurements were made using a Thermo Scientific Element 2 ICP-MS. File descriptions:Table S1. Core top sample site information. References for age control: (Archer, 1996; Balsam & McCoy, 1987; Barrows & Juggins, 2005; Bollmann et al., 2002; Catubig et al., 1998; Cortese et al., 2013; Hesse et al., 2011; Kucera et al., 2005; Lynch-Stieglitz et al., 2006; Mix et al., 1999; U. Pflaumann et al., 2003; Uwe Pflaumann et al., 1996; Prell et al., 1999; Schmidt et al., 2004) Table S2. Parent triterpenol compounds and quantification ion mass/charge ratios for individual PTMEs Table S3. River basin assignments for core top sites Table S4. Uranium/Thorium isotope concentrations and derived bulk sediment fluxes Table S5. Sample biomarker concentrations (ng/g), n-alkane CPI24-36, and n-alkane ACL25-35 Table S6. Sample biomarker fluxes (ng/cm2/kyr) Table S7. Plant-wax n-alkane carbon isotopes (d13C ‰ VPDB) Table S8. Linear correlation coefficients R between d13C values of n-alkane homologs (* p