Halocene Sphaerosiderites: Calibrating an Innovative Paleoclimate Proxy
Luis A. Gonzalez and Greg A. Ludvigson, Department of Geology, The University of Iowa

The University of Iowa Cretaceous Studies Group is pioneering the application of a new stable isotopic proxy, the meteoric sphaerosiderite line, to investigations of the mid-Cretaceous greenhouse world, a widely-acknowledged analogue for the greenhouse warming expected in the next few centuries. A current limitation of the technique, however, is the lack of any studies of modern examples to calibrate precise quantitative estimates of paleoclimatic and paleohydrologic variables that are encoded in ancient sphaerosiderites. An opportunity to perform these calibration experiments has been opened by: (1) the new discovery of modern sphaerosiderites in recent alluvial deposits of the Mississippi River, and (2) our successful recruitment of two highly capable and motivated graduate students to pursue team research on both the solid and fluid geochemistry of these sites. Funds are requested from CGRER to support part of this effort.