Paleoceanographic records in the Chukchi Basin, western Arctic Ocean during the late Quaternary
- PDF / 1,216,456 Bytes
- 12 Pages / 595 x 842 pts (A4) Page_size
- 52 Downloads / 205 Views
Paleoceanographic records in the Chukchi Basin, western Arctic Ocean during the late Quaternary WANG Rujian1∗ , XIAO Wenshen1 , SHAO Lei1 , CHEN Jianfang2 , GAO Aiguo3 1 2 3
State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China Department of Oceanography, Xiamen University, Xiamen 361005, China
Received 17 December 2010; accepted 25 August 2011 ©The Chinese Society of Oceanography and Springer-Verlag Berlin Heidelberg 2012
Abstract The late Quaternary paleoceanographic changes in the western Arctic Ocean are revealed by quantitative studies of foraminiferal abundance, ice-rafted detritus (IRD) and its mineralogical and petrological compositions, planktonic Neogloboquadrina pachyderma (sin.) (Nps)-δ 18 O and -δ 13 C, biogenic and non-biogenic components in Core M03 token from the Chukchi Basin during the Second Chinese National Arctic Expedition cruise. Seven IRD events appeared at MIS 7, 5, 3 and 1. These IRD were carried in massive icebergs, which were exported to the Beaufort Sea through the M’Clure Strait Ice Stream, Canadian Arctic Archipelago, and then transported into the Chukchi Basin by the Beaufort Gyre. Low IRD deposition occurred during the glacial times when more extended ice cover and weakened Beaufort Gyre, while the open water condition and the intensified Beaufort Gyre during interglacial periods favored the IRD deposition. Therefore, the IRD events not only indicate the provenance of coarser detritus and ice export events, but also reflect the evolutionary histories of the Beaufort Gyre and North American ice sheet. Seven light Nps-δ 18 O and -δ 13 C excursions could respond to enhanced rates of sea ice formation resulting in the production and sinking of isotopically light brines, but was irrelevant to the warm Atlantic water and freshwater inputs. Whereas, the heavy Nps-δ 18 O and -δ 13 C values separately reflect the lessened Arctic freshwater and Pacific water, and well-ventilated surface water from the continental shelf and halocline water. Variations of CaCO3 content and planktonic foraminiferal abundance during the interglacial and glacial periods can demonstrate the incremental or diminishing input of the Atlantic water, while the total organic carbon (TOC) and opal contents increased and decreased during the glacial and interglacial periods, respectively, which could be related to the TOC degradation, opal dissolution and redox conditions of interface between the bottom water and sediments. Key words: IRD events, ice sheet, light Nps-δ 18 O and -δ 13 C excursions, surface productivity, late Quaternary, Arctic Ocean Chukchi Basin
nary times, thus incurring dramatic changes within and far beyond the Arctic Ocean (Darby et al., 2006). The Arctic Ocean during the Quaternary was affected immensely by repeated formation of large ice sheets in the Arctic and associated with sea-level fluctuations. This includes the exposure/inundation of shallow shelves, dramatic changes in water-excha
Data Loading...
