SEDIMENTARY GEOCHEMISTRY OF THE MESOPROTEROZOIC BLUE BILLY FORMATION, WESTERN AUSTRALIA, AND IMPLICATIONS FOR GLOBAL OCEAN REDOX DURING THE MESOPROTEROZOIC

The Mesoproterozoic represents an important transition in Earth history because the era sits in between clear environmental perturbations in the early Paleoproterozoic and the rise of early animals in the Neoproterozoic. To better understand the relationship between environmental change and biotic evolution we investigated the sedimentary geochemistry of the Blue Billy Formation located in Western Australia. The Blue Billy Formation was deposited in a relatively deep, flooded intracratonic basin deposited at the beginning of the Calymmian (~1600Ma). Previously generated major and trace element data have indicated relatively high molybdenum (to 112 ppm) and phosphorus (to 0.97 weight percent) concentrations relative to other studied Mesoproterozoic shale units. To complement the elemental data, we analyzed iron speciation and total organic carbon concentrations. Our results will be used to track bottom-water redox conditions in this basin and to compare to similar data from other published studies. Finally, these new data will be compiled with sedimentary geochemical data in the Sedimentary Geochemistry and Paleoenvironments Project Phase 2 data release to track global bottom water redox changes from the Paleoproterozoic and Mesoproterozoic through the Paleozoic.