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Long-term accumulation of carbonate shells reflects a 100-fold drop in loss rate

2014; Geological Society of America; Volume: 42; Issue: 9 Linguagem: Inglês

10.1130/g35694.1

1943-2682

Adam Tomášových, Susan M. Kidwell, Rina Foygel Barber, Darrell S. Kaufman,

Geology and Paleoclimatology Research

Research Article| September 01, 2014 Long-term accumulation of carbonate shells reflects a 100-fold drop in loss rate Adam Tomašových; Adam Tomašových * 1Geological Institute, Slovak Academy of Sciences, Dubravska cesta 9, 84005 Bratislava, Slovakia *E-mail: geoltoma@savba.sk. Search for other works by this author on: GSW Google Scholar Susan M. Kidwell; Susan M. Kidwell 2Department of Geophysical Sciences, University of Chicago, 5734 S. Ellis Avenue, Chicago, Illinois 60637, USA Search for other works by this author on: GSW Google Scholar Rina Foygel Barber; Rina Foygel Barber 3Department of Statistics, University of Chicago, 5734 S. University Avenue, Chicago, Illinois 60637, USA Search for other works by this author on: GSW Google Scholar Darrell S. Kaufman Darrell S. Kaufman 4School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Campus Box 4099, Flagstaff, Arizona 86011, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Adam Tomašových * 1Geological Institute, Slovak Academy of Sciences, Dubravska cesta 9, 84005 Bratislava, Slovakia Susan M. Kidwell 2Department of Geophysical Sciences, University of Chicago, 5734 S. Ellis Avenue, Chicago, Illinois 60637, USA Rina Foygel Barber 3Department of Statistics, University of Chicago, 5734 S. University Avenue, Chicago, Illinois 60637, USA Darrell S. Kaufman 4School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Campus Box 4099, Flagstaff, Arizona 86011, USA *E-mail: geoltoma@savba.sk. Publisher: Geological Society of America Received: 20 Mar 2014 Revision Received: 24 Jun 2014 Accepted: 25 Jun 2014 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2014 Geological Society of America Geology (2014) 42 (9): 819–822. https://doi.org/10.1130/G35694.1 Article history Received: 20 Mar 2014 Revision Received: 24 Jun 2014 Accepted: 25 Jun 2014 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Adam Tomašových, Susan M. Kidwell, Rina Foygel Barber, Darrell S. Kaufman; Long-term accumulation of carbonate shells reflects a 100-fold drop in loss rate. Geology 2014;; 42 (9): 819–822. doi: https://doi.org/10.1130/G35694.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Shells in modern seabeds can be thousands of years old, far older than would be extrapolated from the rapid rates of shell loss detected in short-term experiments. An extensive shell-dating program on the Southern California (USA) shelf permits rigorous modeling of the dynamics of shell loss in the mixed layer, discriminating the key rates of carbonate disintegration and sequestration for the first time. We find that bivalve shells experience an initially high disintegration rate λ1 (∼ decadal half-lives) but shift abruptly, within the first ∼500 yr postmortem, to a 100-fold lower disintegration rate λ2 (∼ millennial half-lives) at sequestration rate τ (burial and/or diagenetic stabilization). This drop permits accrual of a long tail of very old shells even when sequestration is very slow, and allows only a minority (<1%) of all shells to survive the first phase. These high rates of disintegration and low rates of sequestration are consistent with independent measures of high carbonate loss and slow sedimentation on this shelf. Our two-phase model thus reveals significant spatial and temporal partitioning of carbonate loss rates within the mixed layer, and shows how shell age-frequency distributions can yield rigorous and realistic estimates of carbonate recycling on geological time scales. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.