CGRG Bibliography of Canadian Geomorphology
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Author : Flower, B.P.; and Bond, R.L.
Date : 2009.
Title : Solar forcing of ice-rafting in the North Atlantic during the Late Holocene?
Publication : 2009 American Geophysical Union Fall Meeting. December 14-18, 2009. San Francisco, California, USA.
Issue :
Page(s) :
Abstract
In a very influential and controversial paper published in 2001, Gerard Bond and others presented evidence from North Atlantic sediments that ice-rafting closely tracked inferred solar variability during the Holocene (Bond et al., 2001). The evidence came from hematite-stained grains (HSG) from Paleozoic red beds that outcrop in northeastern Greenland and Svalbard, Icelandic volcanic glass, and detrital carbonate from lower Paleozoic rocks in eastern Canada including the Hudson Bay area. Downcore variations were documented in three regions: Feni Drift off Ireland, off eastern Greenland near Denmark Strait, and offshore Newfoundland. In particular, ice-rafted debris (IRD) records from Feni Drift cores KN158-4-MC52 and V29-191 showed changes during the past 3600 years that coincided with 14C production rate changes, as well as the Little Ice Age and the Medieval Warm Period. We have launched a new investigation of HSG and other IRD in North Atlantic cores, in order to (a) verify that the counting techniques can be replicated, (b) examine other cores to investigate the regional coherence of ice-rafting history, (c) conduct robust statistical comparison to improved 14C and 10Be records of solar activity, and (d) assess the climatic linkages between solar activity and ice-rafting. Our preliminary results from Feni Drift cores MC52 and V29-191 replicate published data from the 0-1100 years BP, including maximum percent HSG during the Little Ice Age. Values during the Medieval Warm Period are similar to core-top values. Continuing work on nearby core KN158-4-GGC53 will assess the reproducibility of IRD records in the Feni Drift area, and extend through the late Holocene. These records will be compared to recent reconstructions of solar activity based on 14C and 10Be. Existing data support the suggestion that solar irradiance was an important driver for centennial- to millennial-scale climate change, with strong feedbacks in the North Atlantic region.
Bibliography of Canadian Geomorphology