Marine biogeochemistries of Be and Al: A study based on cosmogenic10Be, Be and Al in marine calcite, aragonite, and opal |
| |
Authors: | Weiquan Dong Devendra Lal Barbara Ransom Wolfgang Berger Marc W Caffee |
| |
Institution: | (1) Geosciences Research Division, Scripps Institution of Oceanography, 92093 La Jolla, CA;(2) Lawrence Livermore National Laboratory, Center for Accelerator Mass Spectrometry, 94551 Livermore, CA;(3) Present address: Geosciences Department, University of Nevada, 4505 Maryland Parkway, Box 454010, 89154-4010 Las Vegas, NV |
| |
Abstract: | The geochemical behaviors of Be and Al in ocean waters have been successfully studied in recent years using natural, cosmogenic,
radioactive10Be and26Al as tracers. The present day dissolved concentrations and distribution of the stable and radioactive isotopes of Be and
Al in ocean waters have revealed their short residence times and appreciable effects of exchange fluxes at the coastal and
ocean-sediment interfaces. It follows that concentrations of these particle-active elements must have varied in the past with
temporal changes in climate, biological productivity and aeolian flux of continental detritus to the oceans. We therefore
investigated the feasibility of extending the measurements of Be and Al isotope concentrations in marine systems to the 103–106 y BP time scale. We report here the discovery of significant amounts of intrinsic Be and Al in marine foraminiferal calcite
and coral aragonite, and of Al in opal (radiolarians) and aragonite (coral), which makes it possible to determine10Be/Be and26Al/Al in oceans in the past. We also report measured10Be/9Be in foraminiferal calcite in Pacific Ocean cores, which reveal that the concentrations and ratios of the stable and cosmogenic
isotopes of Be and Al have varied significantly in the past 30 ky. The implications of these results are discussed. |
| |
Keywords: | Cosmogenic10Be Be Al marine geochemistry aeolian Be Al |
本文献已被 SpringerLink 等数据库收录! |
|