|
|
 |
|||||||||||||||||
|
|||||||||||||||||
 |
|||||||||||||||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
1 Institute of Geology, Mineralogy and Geophysics, Ruhr University, 44801 Bochum, Germany
2 Institute of Geology, Mineralogy and Geophysics, Ruhr University, 44801 Bochum, Germany, and Ottawa-Carleton Geoscience Centre, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
Sr concentrations in Phanerozoic biological calcite suggest a close link between fluctuations in the Sr/Ca ratio of seawater, aragonite versus calcite sedimentation, and the Mg/Ca ratio of seawater, the entire chain being driven by the rate of production and hydrothermal alteration of the oceanic crust. Model simulations suggest that variations in hydrothermal and continental weathering fluxes cannot be the sole reason for the observed Phanerozoic seawater Sr/Ca trend. Changing Sr burial in marine carbonates is likely the most important mechanism that can explain the experimental data. During episodes of high seawater Mg/Ca ratios, aragonite was preferentially deposited, resulting in low seawater Sr/Ca ratios. At low Mg/Ca ratios, calcite was the dominant carbonate sediment, and the Sr/Ca ratio of seawater was high. The evidence for changing chemistry of seawater also has implications for the application of the Sr/Ca and Mg/Ca paleothermometers, in particular for pre-Quaternary samples, and for the assessment of diagenetic alteration of fossil skeletal carbonates by using Sr/Ca ratios.
Key Words: seawater • strontium • calcite • geochemical models • Phanerozoic
This article has been cited by other articles:
|
|
 |
|
  L. Angiolini, F. Jadoul, M. J. Leng, M. H. Stephenson, J. Rushton, S. Chenery, and G. Crippa How cold were the Early Permian glacial tropics? Testing sea-surface temperature using the oxygen isotope composition of rigorously screened brachiopod shells Journal of the Geological Society, September 1, 2009; 166(5): 933 - 945. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Korte, S. P. Hesselbo, H. C. Jenkyns, R. E.M. Rickaby, and C. Spotl Palaeoenvironmental significance of carbon- and oxygen-isotope stratigraphy of marine Triassic-Jurassic boundary sections in SW Britain Journal of the Geological Society, May 1, 2009; 166(3): 431 - 445. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Copper and E. Edinger Distribution, geometry and palaeogeography of the Frasnian (Late Devonian) reef complexes of Banks Island, NWT, western arctic, Canada Geological Society, London, Special Publications, January 1, 2009; 314(1): 109 - 124. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. Ribeiro Da Costa, F. J.A.S. Barriga, and R. N. Taylor Late seafloor carbonate precipitation in serpentinites from the Rainbow and Saldanha sites (Mid-Atlantic Ridge) European Journal of Mineralogy, April 1, 2008; 20(2): 173 - 181. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Yan, A. Munnecke, T. Steuber, E. H. Carlson, and Y. Xiao Marine Sepiolite in Middle Permian Carbonates of South China: Implications for Secular Variation of Phanerozoic Seawater Chemistry Journal of Sedimentary Research, May 1, 2005; 75(3): 328 - 338. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. K. Lowenstein, L. A. Hardie, M. N. Timofeeff, and R. V. Demicco Secular variation in seawater chemistry and the origin of calcium chloride basinal brines Geology, October 1, 2003; 31(10): 857 - 860. [Abstract] [Full Text] [PDF]
|
|
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
