Sources of Ice-Rafted Detritus and Iceberg Tracks in the Arctic Ocean

AOS_SR96_23
Page Navigation
95

ing the elemental composition of iron oxide grains and percentages of grain

types in Arctic Ocean deep-sea sediment cores to potential sources around the

Arctic Ocean. This "fingerprinting" technique required prior characterization

of source areas in the Arctic providing debris that could be rafted into the

central Arctic Ocean by icebergs or sea ice. Eleven statistically unique source

areas were defined by grain type percentages and microprobe chemical analy-

ses of thousands of individual iron oxide grains (Darby and Bischof 1996).

Erk Reimnitz col-

lecting sediment

from the ice.

For the first time the sources of ice-rafted grains in the Arctic Ocean were

traced with a high level of statistical probability. This allowed us to recon-

struct the ice drift tracks and the ocean surface currents in the past and to get

a better understanding of the nature and history of Arctic glaciations. Finally

the potential of pollutants being spread throughout the Arctic Ocean from

point sources on the Russian shelves can be assessed.

The major sources of detritus in 17 of the deep-sea cores thus far analyzed

(4 of 18 cores from the AOS-94 cruise and 13 from previous expeditions) are

the Banks and Victoria Island area and the Sverdrup Basin area around Ellef

Ringnes Island and northern Melville Island. The Mackenzie River basin con-

Dennis Darby and Jens Bischof are with the Department of Geological Sciences at Old Dominion University in

Norfolk, Virginia, U.S.A.