Pleistocene climatic history reflected in planktonic foraminifera from ODP Site 1073 (Leg 174A), New Jersey margin, NW Atlantic Ocean

• Published in: Marine micropaleontology 2004-06, Vol.51 (3), p.213-238
• Main Authors: Olson, Hilary Clement, Smart, Christopher W
• Format: Article
• Language: English
• Subjects: Emiliania huxleyi; Globigerina bulloides; Globigerinita glutinata; Globorotalia inflata; Leg 174A; Marine; Neogloboquadrina pachyderma; New Jersey margin; Ocean Drilling Program; paleoclimatology; planktonic foraminifera; Pleistocene; Pseudoemiliania lacunosa; Site 1073; Turborotalita quinqueloba
• ISSN: 0377-8398; 1872-6186
• DOI: 10.1016/j.marmicro.2003.11.002

Abundance records of planktonic foraminifera (>150 μm) from the upper 520 m of ODP Site 1073 (Hole 1073A, Leg 174A, 639 m water depth) have been integrated with SPECMAP-derived isotope stratigraphy, percentage of calcium carbonate, and coarse sediment fraction data in order to investigate the Pleistocene climatic history of the New Jersey margin. Six planktonic taxonomic groups dominate the foraminiferal assemblage at Site 1073: Neogloboquadrina pachyderma (d) (mean 33.8%), Turborotalita quinqueloba (18.5%), N. pachyderma (s) (18.4%), Globigerina bulloides group (11.4%), Globorotalia inflata group (9.4%), and Globigerinita glutinata (4.1%). Based on the distributions of these six foraminiferal groups, the Pleistocene section can be divided into three paleoclimatic intervals: Interval I (intermediate) corresponds to the Quaternary sediments from sequence boundary pp1 to the seafloor (79.5–0 mbsf; Emiliania huxleyi acme [85 ka] at 72 mbsf); Interval II (warm) occurs between sequence boundaries pp3 and pp1 (325–79.5 mbsf; last occurrence of Pseudoemiliania lacunosa [460 ka] at 330 mbsf); and Interval III (coldest) occurs between sequence boundaries pp4 and pp3 (520–325 mbsf; Calcareous nannofossils and dinocysts in proximity to pp4 indicate that the sedimentary record for 0.9–1.7 Ma is either missing altogether or highly condensed within the basal few meters of the section). Neogloboquadrina pachyderma (d) displays eight peaks of abundance which correlate, for the most part, with depleted δ 18O values, increases in calcium carbonate percentages, low coarse fraction percentages, increased planktonic fragmentation (greater dissolution), and low N. pachyderma (s) abundances. These intervals are interpreted as representing warmer/interglacial conditions. Neogloboquadrina pachyderma (s) displays seven peaks of abundance which correlate, for the most part, with δ 18O increases, decreases in calcium carbonate percentages, increases in coarse fraction percentages, and low N. pachyderma (d) abundances. These intervals are interpreted as representing cooler/glacial conditions. In Interval III, a faunal response to relative changes in sea-surface temperature is reflected by abundance peaks in Neogloboquadrina pachyderma (d), followed by Turborotalita quinqueloba and then N. pachyderma (s) (proceeding from warmest to coolest, respectively). This tripartite response is consistent with the oxygen isotope record and, although not as clear, also occurs in Intervals I and II.