Ocean Drilling Program, United States

Leg 182 will drill a transect of 10 sites from the shelf-edge (200 m) to the middle continental rise (4465 m) in the western Great Australian Bight. The primary drilling objective is a more detailed understanding of global environmental change in high- to mid-latitude settings. Cores from different facies deposited in various water depths during a range of geologic periods will yield the detailed anatomy of a Cenozoic cool-water carbonate margin. The response of this depositional system to sea-level fluctuations will be compared to records from warm-water, rimmed, and unrimmed carbonate platforms to test and refine the global sea-level curve and, most importantly, to describe the reaction of cool-water carbonate depositional systems to different phases of the sea level cycle. Biological and chemical paleoenvironmental proxies will be used to decipher a detailed paleoceanographic record to more precisely describe the timing and paleoceanographic effects of the opening of the Tasman Gateway and the influence of the Leeuwin Current on paleoproductivity over time. The shelf-to-basin transect will also provide high-resolution data on the tempo and pattern of biotic evolution in oceanic and neritic environments. Secondary objectives are directed toward understanding the hydrology of a carbonate platform adjacent to a vast inland karst with sluggish water circulation, and the nature of early burial diagenesis (lithification and dolomitization) in a cold, seawater-dominated system.