Climatic Forcing of Cyclic Carbonate Sedimentation During the Last 5.4 Million Years Along the West Florida Continental Margin

Late Pleistocene Emergence of Crystalline Canadian Shield Sources in Sediments of the Northern Gulf of Mexico

“…Sixty-eight samples were selected for sedimentological and geochemical analyses from ODP Leg 100 Site 625 Hole B (28°49.9'N, 87°09.6'W; 889 m water depth), located on the West Florida Slope in the Gulf of Mexico from three isolated intervals defined as the EP, MP, and LP. Details of stratigraphy, lithology, and composition of the sediments, as well as previous paleoceanographic proxy interpretations of ODP Site 625 have been described previously (Rabinowitz et al, 1985;Roof et al, 1991). The age model was developed by correlating the ODP Site 625 Globigerinoides ruber planktic oxygen isotope (δ 18 O) records from Whitaker (2008) and Joyce et al (1990) from 0-131.22 m below the sea floor (mbsf) to the LR04 stack (Lisiecki & Raymo, 2005) using an inverse mapping procedure developed by Martinson et al (1982) All analyses to evaluate weathering characteristics and provenance of samples were performed on the finegrained siliciclastic clay fraction (i.e., carbonate and organic matter removed; <2 µm grain size), which were extracted by gravitational settling (Stokes' Law) after treatment with acetic acid (20% CH 3 COOH) and hydrogen peroxide (20% H 2 O 2 ).…”

“…Samples were chosen based on the planktonic δ 18 O stratigraphies of Joyce et al (1993), Whitaker (2008) and Shakun et al (2016) (Figure 2a), with light δ 18 O anomalies in the planktonic foraminifera that extend back as far as 2.5 Ma interpreted as meltwater anomalies from the LIS. Detrital material from this site contains fine terrigenous sediment derived from the Mississippi, Apalachicola, and Mobile drainages (Mitchum, 1978;Roof et al, 1991). Samples were selected from glacial, interglacial, and transitional intervals as well as previously identified melt-water pulses, from the middle to late Pleistocene (0-440 ka; referred herein as late Pleistocene; LP), mid-Pleistocene (800-1045 ka during the MPT; MP), and early Pleistocene (2245-2810 ka; EP).…”