Analysis of Miocene stratigraphy and sedimentology in the Ross Sea, Antarctica: a first order test of proxy based climate interpretations

• Main Author: Gray, Samuel
• Format: Text
• Language: unknown
• Published: LSU Scholarly Repository 2007
• Subjects: mms; mmco; Earth Sciences; Antarc*; Antarctica; Ice Sheet; Ross Sea; Whillans Ice Stream
• Online Access: https://repository.lsu.edu/gradschool_theses/395; https://doi.org/10.31390/gradschool_theses.395; https://repository.lsu.edu/context/gradschool_theses/article/1394/viewcontent/uc.pdf

During the Cenozoic, the climate progressed from global warmth into an icehouse world. This study investigates the links between the development of the climate and cryosphere using sediment flux and stratal geometries. The current polar conditions are characterized by dry basal conditions, which due to minimal melt water produce significantly less sediment than their temperate counterparts. Therefore, the transition from temperate to polar conditions should have resulted in marked decrease in sediment flux and change in stratal geometries in adjacent marine margins. Regional seismic stratigraphic evidence clearly suggests that ice has been intermittently grounded on the Ross Sea outer continental shelf since at least the early Miocene. Sedimentation rates and fluxes were calculated from the Ross Sea outer continental shelf and deepwater ODP/DSDP sites to deduce changing climate conditions. The compilation of sedimentation rates coupled with stratal evidence from the Ross Sea outer continental shelf, indicate a dynamic temperate ice sheet likely existed through most of the early and middle Miocene. Following the Middle Miocene Shift, most areas experienced a decrease in sediment accumulation, interpreted to represent the initial onset of polar conditions. The return to high accumulation rates in the early Pliocene most likely represents the return to temperate conditions. The final shift to the present polar conditions occurred during the late Pliocene, and is represented by a decrease in sediment accumulation rates. The low rates are similar to those estimated for the late Miocene and are consistent with low flux estimated for the modern Whillans ice stream in the Ross Sea.