Salty Tales of Diagenesis in Antarctica

Explore the fascinating world of diagenesis in Antarctica through this 58-minute lecture. Delve into the occurrence of highly saline brine groundwater in the McMurdo Dry Valleys and Victoria Land Basin, and its role in precipitating calcite, dolomite, and aragonite cement in Cenozoic glaciomarine strata. Examine the relationship between depth, sediment age, and cement precipitation temperature, suggesting cement and brine formation during periods of cooling and ice sheet expansion. Investigate stratigraphy, sedimentology, petrography, and geochemistry of the Ross Sea and McMurdo Dry Valleys. Analyze lithofacies records and recurring stratigraphic motifs reflecting climatic conditions. Discover insights from the ANDRILL project, including pore water profiles and isotopic data indicating brine derived from seawater freezing. Learn about clumped isotope paleothermometry and its application in understanding cement precipitation. Explore potential sites of brine formation in the McMurdo region and the presence of mirabilite along coastlines. Consider the timing of brine formation and cement precipitation, possibly associated with the Middle Miocene Climate Transition.

Intro
Stratigraphy, sedimentology, petrography, and geochemi
Ross Sea WAIS
McMurdo Dry Valleys
Lithofacies record subglacial to open mari environments Ice contact
Recurring stratigraphic motifs reflect clima conditions
Origin of cement: isotopic insights
"Pristine" aragonitic shells are geochemically altered
Some answers from ANDRILL First drilling project to include routine pore water sampling
Pore water profiles (AND-2A)
Ratios of conservative elements indicate by derived from seawater
Brine exclusion during sea ice formatios
Evaporation and freezing produce distinct relationships among Na-S04-Br
Data indicate that the brine is a product of seawater freezing
Clumped isotope paleothermometry
Temperature calibration using synthetic carbonates
Did cement in AND-2A precipitate from brig
How extensive is the brine?
Potential sites of brine formation in the McMurdo region
Mirabilite is present along coastlines in SMA Contains inclusions of marine sediment Sulfate isotopes consistent with marine origin
Timing of brine formation, cement precipite
Brine formation associated with Middle Miocene Climate Transition?
Ongoing work