AAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
Lacustrine Microbialites in Great Salt Lake; Life in a Dead Lake
(1) Geography, University of Utah, North Salt Lake, UT.
(2) Scripps Institution of Oceanography, La Jolla, CA.
(3) BG Group, Reading, United Kingdom.
Digital bathymetric data obtained during recent surveys of Great Salt Lake, Utah revealed widespread small-scale variations in benthic rugosity, unexpected in a large intermontane continental basin. Examination of one of the areas of increased rugosity revealed widespread lacustrine microbialites. Sediment distribution maps of Great Salt Lake published in 1938 reported the occurrence of lacustrine microbialites along the shallow margins of the lake but did not provide any evidence for the occurrence of these forms in the deeper areas. To investigate the occurrence and distribution of lacustrine microbialite forms in Great Salt Lake, a series of systematic surveys were performed in those areas of the lake exhibiting increased benthic rugosity. Extensive areas of lacustrine microbialite forms were mapped using co-georegistered CHIRP sub-bottom and side scan sonar systems. These data provide detailed information on the occurrence, distribution, size, shape, and spacing of individual microbialite structures and larger morphologic forms. Integrated data from the sidescan sonar and CHIRP surveys reveal that the occurrence of the microbialite forms are frequently associated with fault-controlled microtopographic differences. By integrating this new data with information on the physical, chemical, and hydrologic characteristics of the lake, it is possible to devise a geospatial model for microbialite distribution in Great Salt Lake. Using this information, we can begin to set limits on controls for microbialite occurrence and distribution, and examine associated environmental conditions for lacustrine microbialite growth.