The transition on North America from the warm humid Pliocene to the glaciated Quaternary traced by eolian dust deposition at a benchmark North Atlantic Ocean drill site

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doi: 10.1016/j.quascirev.2014.04.005
Author(s): Lang, David C.; Bailey, Ian; Wilson, Paul A.; Beer, Christopher J.; Bolton, Clara T.; Friedrich, Oliver; Newsam, Cherry; Spencer, Megan R.; Gutjahr, Marcus; Foster, Gavin L.; Cooper, Matthew J.; Milton, J. Andrew
Author Affiliation(s): Primary:
University of Southampton, National Oceanography Centre-Southampton, Southampton, United Kingdom
Volume Title: Quaternary Science Reviews
Source: Quaternary Science Reviews, Vol.93, p.125-141. Publisher: Elsevier, International. ISSN: 0277-3791
Note: In English. 150 refs.; illus., incl. sketch map
Summary: We present Plio-Pleistocene records of sediment color, %CaCO3, foraminifer fragmentation, benthic carbon isotopes (δ13C) and radiogenic isotopes (Sr, Nd, Pb) of the terrigenous component from IODP Site U1313, a reoccupation of benchmark subtropical North Atlantic Ocean DSDP Site 607. We show that (inter)glacial cycles in sediment color and %CaCO3 pre-date major northern hemisphere glaciation and are unambiguously and consistently correlated to benthic oxygen isotopes back to 3.3 million years ago (Ma) and intermittently so probably back to the Miocene/Pliocene boundary. We show these lithological cycles to be driven by enhanced glacial fluxes of terrigenous material (eolian dust), not carbonate dissolution (the classic interpretation). Our radiogenic isotope data indicate a North American source for this dust (∼3.3-2.4 Ma) in keeping with the interpreted source of terrestrial plant wax-derived biomarkers deposited at Site U1313. Yet our data indicate a mid latitude provenance regardless of (inter)glacial state, a finding that is inconsistent with the biomarker-inferred importance of glaciogenic mechanisms of dust production and transport. Moreover, we find that the relation between the biomarker and lithogenic components of dust accumulation is distinctly non-linear. Both records show a jump in glacial rates of accumulation from Marine Isotope Stage, MIS, G6 (2.72 Ma) onwards but the amplitude of this signal is about 3-8 times greater for biomarkers than for dust and particularly extreme during MIS 100 (2.52 Ma). We conclude that North America shifted abruptly to a distinctly more arid glacial regime from MIS G6, but major shifts in glacial North American vegetation biomes and regional wind fields (exacerbated by the growth of a large Laurentide Ice Sheet during MIS 100) likely explain amplification of this signal in the biomarker records. Our findings are consistent with wetter-than-modern reconstructions of North American continental climate under the warm high CO2 conditions of the Early Pliocene but contrast with most model predictions for the response of the hydrological cycle to anthropogenic warming over the coming 50 years (poleward expansion of the subtropical dry zones). Abstract Copyright (2014) Elsevier, B.V.
Year of Publication: 2014
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Alkaline earth metals; Atlantic Ocean; C-13/C-12; Calcium carbonate; Carbon; Cenozoic; Chemostratigraphy; Clastic sediments; Cores; Dust; Expedition 306; Expeditions 303/306; Foraminifera; IODP Site U1313; Integrated Ocean Drilling Program; Invertebrata; Isotope ratios; Isotopes; Lead; Lithostratigraphy; Marine sediments; Metals; Microfossils; Mid-Atlantic Ridge; Nd-144/Nd-143; Neodymium; Neogene; North America; North Atlantic; O-18/O-16; Oxygen; Paleoclimatology; Pb-206/Pb-204; Pb-207/Pb-204; Pb-208/Pb-204; Pliocene; Protista; Provenance; Quaternary; Radioactive isotopes; Rare earths; Sediments; Sr-87/Sr-86; Stable isotopes; Strontium; Terrigenous materials; Tertiary; Transport; Wind transport
Coordinates: N410000 N410000 W0325700 W0325700
Record ID: 2015118448
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands