Class

Article

Presentation Type

Poster Presentation

Abstract

Stromatolites are accretionary structures that form mainly from bacteria colonization in subaqueous environments and comprise mostly calcium carbonate (CaCO3). They can be found throughout the rock record (Archean-present day) and modern stromatolites are now restricted to areas that have few or no grazing animals. The hypersaline Great Salt Lake in Utah is host to numerous modern stromatolites, which are currently exposed to the air because of low lake levels. Here, we present C and O isotopic data and radiocarbon dates from a transect of a stromatolite dome (SD-1-01). Carbon and oxygen isotopic values covary strongly along the transect and range from 0.97 ‰ to 6.64 ‰ PDB for D13C and -4.33 ‰ to -1.19 ‰ PDB for D18O. These data agree well with prior work performed on lake core sediments and are strongly indicative of a hydrologically-closed basin. Additionally, the pronounced fluctuations in D13C and D18O throughout the transect are likely the result of changes in water chemistry and/or climate. Radiocarbon dates along the transect allow us to constrain when these changes occurred and correspond them to known climactic events.

Start Date

4-14-2016 9:00 AM

End Date

4-14-2016 10:15 AM

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Geology Commons

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Apr 14th, 9:00 AM Apr 14th, 10:15 AM

Stable isotope and radiocarbon analysis of modern lacustrine stromatolites near Great Salt Lake, Utah

Stromatolites are accretionary structures that form mainly from bacteria colonization in subaqueous environments and comprise mostly calcium carbonate (CaCO3). They can be found throughout the rock record (Archean-present day) and modern stromatolites are now restricted to areas that have few or no grazing animals. The hypersaline Great Salt Lake in Utah is host to numerous modern stromatolites, which are currently exposed to the air because of low lake levels. Here, we present C and O isotopic data and radiocarbon dates from a transect of a stromatolite dome (SD-1-01). Carbon and oxygen isotopic values covary strongly along the transect and range from 0.97 ‰ to 6.64 ‰ PDB for D13C and -4.33 ‰ to -1.19 ‰ PDB for D18O. These data agree well with prior work performed on lake core sediments and are strongly indicative of a hydrologically-closed basin. Additionally, the pronounced fluctuations in D13C and D18O throughout the transect are likely the result of changes in water chemistry and/or climate. Radiocarbon dates along the transect allow us to constrain when these changes occurred and correspond them to known climactic events.