HR: 11:20h
AN: PP41D-05    [PDF]
TI: Cold Water Coral Mounds and Early Holocene Climate Change
AU: Readman, P W
EM: pr@cp.dias.ie
AF: Dublin Institute for Advanced Studies, 5 Merrion Square, Dublin, 2 Ireland
AU: * O'Reilly, B M
EM: bor@cp.dias.ie
AF: Dublin Institute for Advanced Studies, 5 Merrion Square, Dublin, 2 Ireland
AU: Shannon, P M
EM: p.shannon@ucd.ie
AF: Department of Geology, University College Dublin, Dublin, 4 Ireland
AB: Cold-water coral mounds occur in discrete clustered populations over a broad region from the glaciated Norwegian continental margins to the non-glaciated margins of Iberia and northwest Africa. They are potentially sensitive indicators of change in oceanic circulation, coupled to past climate change. Here we report on an interesting correlation between the Holocene growth of a mound population west of Ireland and early Holocene palaeoclimatic variations in the North Atlantic region, notably the well documented 8.2 kyr cold event. An accurate age structure for the mound population is calculated using recent growth rate estimates for the main coral framework constructor {\it L. pertusa} and a previously formulated population growth model. The calculated curve for the Holocene period fits the observed population data well, except for a pronounced and significant deflection in the data trend beginning at about 8500 calendar years (cal. yr) ago in the early Holocene. This date corresponds to the time ($~$8470 cal. yr) that the glacial lakes Agassiz and Ojibway, which were once dammed by a remnant of the Laurentide ice sheet, drained catastrophically into the Labrador sea releasing $>$10$^{14}$ m$^{3}$ of fresh water. The 8.2 kyr event had as much a global effect on the large-scale structure of deep-water aphotic ecosystems as it did on continental shelf and terrestrial ecosystems.
DE: 3344 Paleoclimatology
DE: 4800 OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting