Deglaciation of the Champlain Valley New York and Vermont and its possible effects on North Atlantic climate change
- 出版日期：2004.
- 页数：1 v. :
- 第一责任说明：John Allen Rayburn.
- 分类号：a226.4 ; a133
- ISBN：0496736264(ebk.) :
MARC全文
02h0029397 20120613135828.0 cr un||||||||| 120612s2004 xx ||||f|||d||||||||eng | 3126340 0496736264(ebk.) : CNY371.35 NGL NGL NGL a226.4 ; a133 Rayburn, John Allen. Deglaciation of the Champlain Valley New York and Vermont and its possible effects on North Atlantic climate change [electronic resource] / John Allen Rayburn. 2004. 1 v. : digital, PDF file. Adviser: Knuepfer, Peter L. K. Thesis (Ph.D.)--State University of New York at Binghamton, 2004. Changes in the flux of fresh water directed into the North Atlantic may affect thermohaline ocean circulation, resulting in regional climate change. Thermohaline circulation may have been more sensitive to these meltwater flux changes during the last deglaciation when large volumes of fresh meltwater from proglacial lakes on the North American continent discharged into the North Atlantic. This study examines the proglacial lake record in the northern Champlain Valley to determine the chronology and magnitude of meltwater discharge through and from this region. Steady-state baseflow) meltwater flux is estimated to have been about 0.03--0.06 Sv 1 Sv ＝ 106 m 3/s), based on threshold morphology. Digital elevation paleo-bathymetric models of the proglacial lakes in the St. Lawrence Lowlands and Champlain Valley were created from mapped strandlines. These models determined that two short duration floods with discharges on the order of 0.1--0.2 Sv entered the Atlantic Ocean through the Hudson Valley. This was followed about 150--300 years later by a switch of steady-state flux from the Hudson Valley to the Gulf of St. Lawrence initiated by a 0.1--0.2 Sv short duration flood pulse to the Atlantic through the Gulf of St. Lawrence. These flood pulses and the switch of the steady-state discharge route may have had a significant impact on thermohaline ocean circulation. Terrestrial organic radiocarbon ages combined with the sedimentary record suggest that the switch in discharge route from the Hudson Valley to the Gulf of St. Lawrence, associated with the final draining of glacial Lake Vermont and the incursion of the Champlain Sea in the Champlain Valley, occurred at about 12,830 years B.P. This is about the same time as the onset of the Younger Dryas cold episode. Deglaciation of the Champlain Valley was emulated using a finite element computer model, paleo-bathymetric meltwater volumes, and simple assumptions about Earth rheology, to see how well a modified ICE-3G glacial model would predict observed isostatic deformation. Mapped strandlines indicate that 13,000 years of isostatic rebound in the Champlain Valley resulted in uplift with nearly linear slope uplift profile trending south to north at 0.8--0.9 m/km through the Champlain Valley. The model predicted an increasing slope uplift profile trending southeast to northwest at 0.4--0.5 m/km through the Champlain Valley. Climatic changes ; Ocean circulation North Atlantic Region. ; North Atlantic Region. Electronic dissertations. aeBook. aCN bNGL http://pqdt.bjzhongke.com.cn/Detail.aspx?pid=hy7GWVr2LZM%3d NGL Bs1476 rCNY371.35 ; h1 bs1204