[Eoas-seminar] Reminder TODAY: EOAS Colloquium speaker this Friday at 3:30 in CAR 101

[eoas-seminar at lists.fsu.edu]

Please join us for our last EOAS colloquium speaker of this semester, TODAY at 3:30 in CAR 101:

Dr. Raj Dasgupta from Rice University  will present:

Origin and Early Differentiation of Life-essential Volatile Elements on Earth

Inventory of volatile elements such as carbon, hydrogen, nitrogen, and sulfur in the rocky reservoirs of inner Solar System objects is critical for their possible evolution towards establishing habitable surface conditions. However, the undifferentiated feedstock materials can undergo early differentiation in a number of different ways that lead to significantly different budgets of C, H, N, S in the early silicate reservoirs of various planets, planetary embryos, and planetesimals.
In this talk, I will use laboratory experimental constraints on the fate of C, H, N, S during accretion and differentiation (e.g., core formation, atmospheric loss, early mantle melting) of rocky bodies, guided by compositions sampled in our own Solar System. The key parameters we will use are partition coefficients of C, N, S, and H between core forming alloy/sulfide melts and silicate melts, solubility constants of volatile gas species in silicate melts (magma oceans), and P-T-dependent solubility of C and N in core forming alloy melt. I will show how with difference in the conditions of core-mantle fractionation (such as depth, temperature, composition, and redox state of alloy-silicate equilibration) and styles of differentiation such as internal differentiation versus magma ocean, low-temperature sulfide segregation, different planetary silicate reservoirs acquire different inventories of C, H, N, S. I will also evaluate how the volatile abundance pattern involving core-mantle equilibration that may be expected for planets’ gradual growth via accretion of undifferentiated planetesimals may differ from those where rocky planets experience punctuated and protracted growth via near-disequilibrium merger of differentiated planetary embryo(s). I will show that Earth's major volatile abundance pattern may be best explained by merger of the proto Earth with a Mars sized body with a sulfur-rich core.


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