Primary U distribution in scleractinian corals and its implications for U series dating
Robinson, Laura F.
Adkins, Jess F.
Fernandez, Diego P.
Burnett, Donald S.
Gagnon, Alexander C.
MetadataShow full item record
In this study we use microsampling techniques to explore diagenetic processes in carbonates. These processes are important as they can affect the accuracy of U series chronometry. Fission track maps of deep-sea scleractinian corals show a threefold difference between the minimum and maximum [U] in modern corals, which is reduced to a factor of 2 in fossil corals. We use micromilling and MC-ICP-MS to make detailed analyses of the [U] and δ234Uinitial distributions in corals from 218 ka to modern. Within each fossil coral we observe a large range of δ234Uinitial values, with high δ234Uinitial values typically associated with low [U]. A simple model shows that this observation is best explained by preferential movement of alpha-decay produced 234U atoms (alpha-recoil diffusion). Open-system addition of 234U may occur when alpha-recoil diffusion is coupled with a high [U] surface layer, such as organic material. This process can result in large, whole-coral δ234Uinitial elevations with little effect on the final age. The diagenetic pathways that we model are relevant to both shallow-water and deep-sea scleractinian corals since both exhibit primary [U] heterogeneity and may be subject to U addition.
Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 7 (2006): Q05022, doi:10.1029/2005GC001138.
Suggested CitationArticle: Robinson, Laura F., Adkins, Jess F., Fernandez, Diego P., Burnett, Donald S., Wang, S.-L., Gagnon, Alexander C., Krakauer, Nir, "Primary U distribution in scleractinian corals and its implications for U series dating", Geochemistry Geophysics Geosystems 7 (2006): Q05022, DOI:10.1029/2005GC001138, https://hdl.handle.net/1912/1046
Showing items related by title, author, creator and subject.
Coral biomineralization, climate proxies and the sensitivity of coral reefs to CO2-driven climate change DeCarlo, Thomas M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2017-02)Scleractinian corals extract calcium (Ca2+) and carbonate (CO2−3) ions from seawater to construct their calcium carbonate (CaCO3) skeletons. Key to the coral biomineralization process is the active elevation of the CO2−3 ...
The origin and role of organic matrix in coral calcification: insights from comparing coral skeleton and abiogenic aragonite DeCarlo, Thomas M.; Ren, Haojia; Farfan, Gabriela A. (Frontiers Media, 2018-05-15)Understanding the mechanisms of coral calcification is critical for accurately projecting coral reef futures under ocean acidification and warming. Recent suggestions that calcification is primarily controlled by organic ...
Wienberg, Claudia; Titschack, Jürgen; Freiwald, Andre; Frank, Norbert; Lundälv, Tomas; Taviani, Marco; Beuck, Lydia; Schröder-Ritzrau, Andrea; Krengel, Thomas; Hebbeln, Dierk (Elsevier, 2018-02-20)The largest coherent cold-water coral (CWC) mound province in the Atlantic Ocean exists along the Mauritanian margin, where up to 100 m high mounds extend over a distance of ∼400 km, arranged in two slope-parallel chains ...