HR: 1330h
AN: PP42A-0860    [PDF]
TI: Depths and Ages of Deep-Sea Corals From the Medusa Expedition
AU: Fernandez, D
EM: diego@gps.caltech.edu
AF: Caltech, MS 100-23 1200 E. California Blvd., Pasadena, CA 91125 United States
AU: * Adkins, J F
EM: jess@gps.caltech.edu
AF: Caltech, MS 100-23 1200 E. California Blvd., Pasadena, CA 91125 United States
AU: Robinson, L F
EM: laurar@gps.caltech.edu
AF: Caltech, MS 100-23 1200 E. California Blvd., Pasadena, CA 91125 United States
AU: Scheirer, D
EM: Daniel_Scheirer@brown.edu
AF: USGS, Mail Stop 989 345 Middlefield Rd, Menlo Park, CA 94025 United States
AU: Shank, T
EM: tshank@whoi.edu
AF: WHOI, MS 33 2-14 Redfield, Woods Hole, MA 02543 United States
AB: From May-June 2003 we used the DSV Alvin and the RSV Atlantis to collect modern and fossil deep-sea corals from the New England and Muir Seamounts. Our goal was to collect depth transects of corals from a variety of ages to measure paleo chemical profiles in the North Atlantic. Because deep-sea corals can be dated with both U-series and radiocarbon methods, we are especially interested in measuring past D14C profiles to constrain the paleo overturning rate of the deep ocean. We collected over 3,300 fossil {\it Desmophyllum cristagalli} individuals, 10s of kgs of {\it Solenosmillia sp.} and numerous {\it Enallopsamia rostrata} and {\it Caryophilia sp.} These samples spanned a depth range from 1,150-2,500 meters and refute the notion that deep-sea corals are too sparsely distributed to be useful for paleoclimate reconstructions. Despite widespread evidence for mass wasting on the seamounts, fossil corals were almost always found in growth position. This observation alleviates some of the concern associated with dredge samples where down-slope transport of samples can not be characterized. Fossil scleractinia were often found to have recruited onto other carbonate skeletons, including large branching gorgonians. The U-series age distribution of these recruitment patterns will constrain how much paleoclimatic time a particular "patch" can represent. In addition, U-series ages, combined with the observed differences in species distribution, will begin to inform our understanding of deep-sea coral biogeography. A lack of modern {\it D. cristagalli} on Muir seamount, but an abundance of fossil samples at this site, is the most striking example of changes in oceanic conditions playing a role in where deep-sea corals grow.
DE: 4267 Paleoceanography
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting