Gruetzner, J. and Higgins, S. M. (2010): Threshold behavior of millennial scale variability in deep water hydrography inferred from a 1.1 Ma long record of sediment provenance at the southern Gardar Drift
Leg/Site/Hole:
Related Expeditions:
IODP 306 ODP 162 IODP 306 U1314 ODP 162 983
Identifier:
ID:
2013-034377
Type:
georefid
ID:
10.1029/2009PA001873
Type:
doi
Creator:
Name:
Gruetzner, J.
Affiliation:
Bremen University, Center for Marine Environmental Sciences, Bremen, Germany
Role:
author
Name:
Higgins, S. M.
Affiliation:
Lamont-Doherty Earth Observatory, United States
Role:
author
Identification:
Title:
Threshold behavior of millennial scale variability in deep water hydrography inferred from a 1.1 Ma long record of sediment provenance at the southern Gardar Drift
Year:
2010
Source:
Paleoceanography
Publisher:
American Geophysical Union, Washington, DC, United States
Volume:
25
Issue:
4
Pages:
Abstract:
Integrated Ocean Drilling Program (IODP) Site U1314 of the North Atlantic is a critical sedimentary archive record of subpolar deep water from the southern Gardar Drift for which we derived an age model of orbital resolution for the last 1.8 Ma. This chronology combined with high-resolution (cm scale) X-ray fluorescence core scanning measurements of major elements allows tracking changes in terrigenous provenance during the last 1.1 Ma. Low Potassium to Titanium (K/Ti) ratios reflect enhanced transport of basalt-derived titanomagnetites during warm climate intervals, while high K/Ti ratios indicate a dominance of acidic sediment sources typical for glacial and stadial events. Changes in K/Ti and magnetic concentration at Site 1314 are coeval with fluctuations in smectite content and grain size data from nearby piston cores, suggesting that the provenance changes are mainly controlled by variable flow of the Iceland-Scotland Overflow Water, an important branch of North Atlantic Deep Water. Furthermore, K/Ti variations on orbital time scales show a striking similarity to the deep sea delta (super 13) C record from ODP Site 607. Pervasive features of the K/Ti time series during and after the Mid-Pleistocene Transition are suborbital changes similar to Dansgaard/Oeschger and Bond oscillations that appear to be strongly amplified during ice growth phases when global benthic delta (super 18) O was within the range of approximately 4.1-4.6 per mil. The strong increase in variability of sediment provenance and subsequently deep hydrography at benthic delta (super 18) O values below approximately 4.1 suggests that the extent of glaciations and, therefore, sea level corresponding to this value constitutes an important physical threshold that was persistent at least for the last 1.1 Ma.
Language:
English
Genre:
Serial
Rights:
URL:
Coverage: Geographic coordinates: North:60.2412 West:-27.5300 East:
-23.3826 South:56.2200
Keywords: Quaternary geology; Atlantic Ocean; Cenozoic; chemostratigraphy; chronostratigraphy; concentration; Expedition 306; Expeditions 303/306; Gardar Drift; Integrated Ocean Drilling Program; IODP Site U1314; isotope ratios; isotopes; Leg 162; magnetic properties; magnetic susceptibility; magnetostratigraphy; major elements; marine sediments; North Atlantic; Northeast Atlantic; O-18/O-16; Ocean Drilling Program; ODP Site 983; oxygen; paleo-oceanography; paleoclimatology; paleomagnetism; provenance; Quaternary; Reykjanes Ridge; sediments; stable isotopes; trace elements;
.