Eustasy and sea water Sr composition: application to high-resolution Sr-isotope stratigraphy of Miocene shallow-water carbonates

Year:

2007

Type of Publication:

Article

Keywords:

Chronostratigraphy, climate, Miocene, sequence stratigraphy, Sr-isotope ratios, stable isotopes

Authors:

Kroeger, K. F.; Reuter, M.; Forst, M. H.; Breisig, S.; Hartmann, G.; Brachert, T. C.

Journal:

Sedimentology

Volume:

54

Number:

3

Pages:

565-585

ISSN:

1365-3091

BibTex:

@article{SED:SED849, author = "K.F. Kroeger and M. Reuter and M.H. Forst and S. Breisig and G. Hartmann and T.C. Brachert", abstract = "Oceanic 87Sr/86Sr-isotope ratios are strongly influenced by rates of silicate weathering and therefore linked not only to glaciation but also to sea-level change. The present study combines analysis of sequence stratigraphy and basin architecture with Sr-isotope stratigraphy in Miocene shallow-water sediments in southern Portugal and Crete (Greece). The common method is to use smoothed global sea water Sr-isotope reference curves but here a different approach is chosen. Instead, measured Sr-isotope curves are correlated with unsmoothed reference curves by identification of similar fluctuations in the order of several 100 kyr. Transgressive intervals are characterized by increasing Sr-isotope ratios interpreted as corresponding to intensified silicate weathering as a consequence of deglaciation, while lowstand deposits have low Sr-isotope ratios. Comparison of Sr-isotope curves and sedimentary sequences in the studied basins with independent global δ18O data and data on global sea-level might suggest a general relationship, supporting a connection to global climate change. Because of these relationships, the method presented herein has a high potential for use in high-resolution age dating and is also applicable in shallow-water sediments.", doi = "10.1111/j.1365-3091.2006.00849.x", issn = "1365-3091", journal = "Sedimentology", keywords = "Chronostratigraphy, climate, Miocene, sequence stratigraphy, Sr-isotope ratios, stable isotopes", number = "3", pages = "565--585", publisher = "Blackwell Publishing Ltd", title = "{E}ustasy and sea water {S}r composition: application to high-resolution {S}r-isotope stratigraphy of {M}iocene shallow-water carbonates", url = "http://dx.doi.org/10.1111/j.1365-3091.2006.00849.x", volume = "54", year = "2007", }

Abstract:

Oceanic 87Sr/86Sr-isotope ratios are strongly influenced by rates of silicate weathering and therefore linked not only to glaciation but also to sea-level change. The present study combines analysis of sequence stratigraphy and basin architecture with Sr-isotope stratigraphy in Miocene shallow-water sediments in southern Portugal and Crete (Greece). The common method is to use smoothed global sea water Sr-isotope reference curves but here a different approach is chosen. Instead, measured Sr-isotope curves are correlated with unsmoothed reference curves by identification of similar fluctuations in the order of several 100 kyr. Transgressive intervals are characterized by increasing Sr-isotope ratios interpreted as corresponding to intensified silicate weathering as a consequence of deglaciation, while lowstand deposits have low Sr-isotope ratios. Comparison of Sr-isotope curves and sedimentary sequences in the studied basins with independent global δ18O data and data on global sea-level might suggest a general relationship, supporting a connection to global climate change. Because of these relationships, the method presented herein has a high potential for use in high-resolution age dating and is also applicable in shallow-water sediments.