Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

Geological Magazine

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by FRANK, T. D. Articles by LYONS, T. W. Search for Related Content GeoRef GeoRef Citation

Changes in organic matter production and accumulation as a mechanism for isotopic evolution in the Mesoproterozoic ocean

T. D. FRANK^*,*, L. C. KAH and T. W. LYONS

^* Department of Earth Sciences, University of Queensland, St Lucia QLD 4072, Australia
Department of Geological Sciences, University of Tennessee, Knoxville TN 37996, USA
Department of Geological Sciences, University of Missouri, Columbia MO 65211, USA

^* Author for correspondence: tfrank2{at}unl.edu; present address: Department of Geosciences, University of Nebraska, Lincoln, NE 68588-0340, USA.

Mesoproterozoic marine successions worldwide record a shift in average ues from 0 to +3.5 , with the latter value evident in successions younger than 1250 Ma. New carbon isotope data from the ~ 300 to 1270 Ma Dismal Lakes Group, Arctic Canada, provide further insight into this fundamental transition. Data reveal that the shift to higher ¹³C values was gradual and marked by occasional excursions to values less than 0 . When compared to records from older and younger marine successions, it is evident that the difference between isotopic minima and maxima increased with time, indicating that the marine system evolved to become isotopically more variable. We interpret these patterns to record an increase in the crustal inventory of organic carbon, reflecting eukaryotic diversification and a change in the locus of organic carbon burial to include anoxic deep marine sites where preservation potential was high. We speculate that the release of O₂ to Earth’s surface environments associated with increased organic carbon storage induced irreversible changes in the Mesoproterozoic biosphere, presaging the more extreme environmental and evolutionary developments of the Neoproterozoic.

Key Words: Mesoproterozoic • carbonate rocks • C-13/C-12 • chemostratigraphy • carbon cycle

This article has been cited by other articles:

				J. Farquhar and D. T. Johnston The Oxygen Cycle of the Terrestrial Planets: Insights into the Processing and History of Oxygen in Surface Environments Reviews in Mineralogy and Geochemistry, January 1, 2008; 68(1): 463 - 492. [Abstract] [Full Text] [PDF]

				D. T. Johnston, B. A. Wing, J. Farquhar, A. J. Kaufman, H. Strauss, T. W. Lyons, L. C. Kah, and D. E. Canfield Active Microbial Sulfur Disproportionation in the Mesoproterozoic Science, December 2, 2005; 310(5753): 1477 - 1479. [Abstract] [Full Text] [PDF]