Datasets generated for O'Mara et al. (2024), Constraining Plio-Pleistocene shifts in Northwest African hydroclimate, ecosystem distributions, and marine productivity: new paleo-records across the Mid-Pleistocene Transition. <i>Paleoceanography and Paleoclimatology</i>.

Organic and inorganic geochemical paleo-proxy measurements from marine sediment core MD03-2705 taken from the Northwest African margin. New samples dating to the Mid-Pleistocene Transition (1.1 – 1.0 Ma) are presented here. Data include plant-wax hydrogen (dD) and carbon (d13C) isotopes; plant-wax concentrations; and constant flux (extraterrestrial 3He) normalized estimates of mass accumulation rates of bulk sediment, dust, opal, and calcium carbonate. 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, helium isotope measurements were made in the LDEO Noble Gas Lab using a MAP-215 mass spectrometer, and carbonate and opal fractions were measured at the LDEO Noble Gas Lab and the Bradtmiller Lab at Macalester College using coulometry and alkaline extraction and molybdate blue spectrophotometry respectively. File descriptions: inorg_table.xlsx includes the inorganic geochemical measurements of helium isotopes, and mass accumulation rates of multiple sedimentary components of each sample. org_iso_table.xlsx includes the isotope measurements of plant-wax n-alkane carbon and hydrogen isotopes (including ice-volume corrections for hydrogen), calculated landscape fraction C4 plants, and precipitation hydrogen isotopes estimated from the C31 n-alkane. alk_conc_table.xlsx includes the concentration of C25-C35 odd chain length n-alkanes in micrograms per gram of dry sediment. All data tables have core depth (cm) and associated age estimates for each sample. event_metadata.xlsx includes the core metadata. meas_metadata.xlsx includes units for each variable across the three data tables.