Constraints on the Pleistocene chronology of sediments from the Lomonosov Ridge

Authors

Matthew O'Regan, University of Rhode Island
John King, University of Rhode Island
Jan Backman, Stockholms universitet
Martin Jakobsson, Stockholms universitet
Heiko Pälike, National Oceanography Centre Southampton
Kathryn Moran, University of Rhode Island
Clifford Heil, University of Rhode Island
Tatsuhiko Sakamoto, Japan Agency for Marine-Earth Science and Technology
Thomas M. Cronin, United States Geological Survey
Richard W. Jordan, Yamagata University

Document Type

Article

Date of Original Version

3-1-2008

Abstract

Despite its importance in the global climate system, age-calibrated marine geologic records reflecting the evolultion of glacial cycles through the Pleistocene are largely absent from the central Arctic Ocean. This is especially true for sediments older than 200 ka. Three sites cored during the Integrated Ocean Drilling Program's Expedition 302, the Arctic Coring Expedition (ACEX), provide a 27 m continuous sedimentary section from the Lomonosov Ridge in the central Arctic Ocean. Two key biostratigraphic datums and constraints from the magnetic inclination data are used to anchor the chronology of these sediments back to the base of the Cobb Mountain subchron (1215 ka). Beyond 1215 ka, two best fitting geomagnetic models are used to investigate the nature of cyclostratigraphic change. Within this chronology we show that bulk and mineral magnetic properties of the sediments vary on predicted Milankovitch frequencies. These cyclic variations record "glacial" and "interglacial" modes of sediment deposition on the Lomonosov Ridge as evident in studies of ice-rafted debris and stable isotopic and faunal assemblages for the last two glacial cycles and were used to tune the age model. Potential errors, which largely arise from uncertainties in the nature of downhole paleomagnetic variability, and the choice of a tuning target are handled by defining an error envelope that is based on the best fitting cyclostratigraphic and geomagnetic solutions. Copyright 2008 by the American Geophysical Union.

Publication Title, e.g., Journal

Paleoceanography

Volume

23

Issue

1

Citation/Publisher Attribution

O'Regan, Matthew, John King, Jan Backman, Martin Jakobsson, Heiko Pälike, Kathryn Moran, Clifford Heil, Tatsuhiko Sakamoto, Thomas M. Cronin, and Richard W. Jordan. "Constraints on the Pleistocene chronology of sediments from the Lomonosov Ridge." Paleoceanography 23, 1 (2008). doi: 10.1029/2007PA001551.