silica rich waters from the

• Main Authors: Lloyd D. Keigwin, Edward A. Boyle
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: PA1101; doi; 10.1029/2007PA001500; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.537.2388; http://boyle.mit.edu/~ed/PDFs/Keigwin(2008)Paleoc23.pdf

[1] Models indicate that a complete shutdown of deep and intermediate water production is a possible consequence of extreme climate conditions in the northern North Atlantic, and the high ratio of 231Pa to 230Th on Bermuda Rise is evidence that this might have happened 17 ka during Heinrich event 1 (H1). However, new radiocarbon data from bivalves that lived at 4.6 km on the Bermuda Rise during H1 lead to a different conclusion. The bivalve data do indeed indicate ventilation of the deep western North Atlantic was suppressed during H1 but not as much as it was during the last glacial maximum. We propose that high diatom flux to the Bermuda Rise during H1 is at least in part responsible for increased 231Pa/230Th at that time. Although we cannot say for sure why opal production was so high in a gyre center location at that time, increased leakage of