Entries by Rajdeep Dasgupta

JGR Planets: The solidus and melt productivity of nominally anhydrous Martian mantle constrained by new high pressure-temperature experiments – Implications for crustal production and mantle source evolution

Shuo Ding, Rajdeep Dasgupta, Kyusei Tsuno   Abstract: We constrained the solidus of a model Martian composition with low bulk Mg# (molar MgO/(MgO + FeOT) × 100 ~75) and high total alkali (Na2O + K2O = 1.09 wt.%) concentration at 2 to 5 GPa by experiments. Based on the new solidus brackets, we provide a […]

AGU Monograph: The effect of variable Na/K on CO2 solubility in slab-derived rhyolitic melts

The effect of variable Na/K on CO2 solubility in slab-derived rhyolitic melts   Michelle Muth, Megan S. Duncan, Rajdeep Dasgupta   Abstract: We conducted high pressure, high temperature experiments to investigate the effect of variable alkali ratio on the CO2‐rich fluid solubility in hydrous rhyolitic melts at sub‐arc depths. Experiments were performed at 3.0 and […]

Nature Geoscience: Great Oxidation and Lomagundi events linked by deep cycling and enhanced degassing of carbon

Great Oxidation and Lomagundi events linked by deep cycling and enhanced degassing of carbon James Eguchi, Johnny Seales, and Rajdeep Dasgupta Abstract For approximately the first 2 billion years of the Earth’s history, atmospheric oxygen levels were extremely low. It was not until at least half a billion years after the evolution of oxygenic photosynthesis, perhaps […]

AJS: The contribution to exogenic CO2 by contact metamorphism at continental arcs: A coupled model of fluid flux and metamorphic decarbonation

The contribution to exogenic CO2 by contact metamorphism at continental arcs: A coupled model of fluid flux and metamorphic decarbonation Xu Chu, Cin-Ty A. Lee, Rajdeep Dasgupta, & Wenrong Cao ABSTRACT. Recent work has suggested a possible temporal coincidence between greenhouse intervals and enhanced arc volcanism, motivating the hypothesis that magmatic and metamorphic CO2 emissions […]

JGR Solid Earth: Phase relations of a depleted peridotite fluxed by a CO2-H2O fluid – Implications for the stability of partial melts versus volatile-bearing mineral phases in the cratonic mantle

Phase relations of a depleted peridotite fluxed by a CO2-H2O fluid – Implications for the stability of partial melts versus volatile-bearing mineral phases in the cratonic mantle Sriparna Saha and Rajdeep Dasgupta Abstract We present phase‐equilibria experiments of a K‐bearing, depleted peridotite (Mg# 92) fluxed with a mixed CO2‐H2O fluid (0.5 wt.% CO2 and 0.94 […]

Cambridge University Press: A framework for understanding whole Earth carbon cycling

A Framework for Understanding Whole-Earth Carbon Cycling Summary This chapter explores how the cycling of carbon in subduction zones and orogenic belts varies with supercontinent cycles and mountain building. It discusses the processes that link short-term and long-term carbon cycling and the timescales of these processes, such as the response times of weathering and atmospheric […]

EPSL: The influence of plate tectonic style on melt production and CO2 outgassing flux at mid-ocean ridges

The influence of plate tectonic style on melt production and CO2 outgassing flux at mid-ocean ridges Jocelyn J. Fuentes, John W. Crowly, Rajdeep Dasgupta, and Jerry X. Mitrovica Ocean ridges are one of the primary connections between Earth’s mantle and surface. Therefore, understanding the evolution of ocean ridge processes through Earth history is important for […]

GRL: Nitrogen in the Earth’s outer core

Nitrogen in the Earth’s outer core Bajgain, S. K., Mookherjee, M., Dasgupta, R., Ghosh, D. & Karki, B. B. Using first principles molecular dynamic simulations, we explore the effects of nitrogen (N) on the density and sound velocity of liquid iron and evaluate its potential as a light element in the Earth’s outer core. Our […]

JPet: Sulfur inventory of ocean island basalt source regions constrained by modeling the fate of sulfide during decompression melting of a heterogeneous mantle

Ding, S. and Dasgupta, R. Abstract: The sulfur (S) and copper (Cu) contents of primitive mid-ocean ridge basalts (MORB) and ocean island basalts (OIB) are similar, although the latter are thought to be derived from hotter mantle. To reconcile the sulfur and chalcophile element budgets of OIB, we developed a model to describe the behavior […]

AJS: Volatile-bearing partial melts beneath oceans and continents – Where, how much, and of what compositions?

Volatile-bearing partial melts beneath oceans and continents – Where, how much, and of what compositions? Abstract: Besides depth and temperature, CO2 and H2O, are the two most important variables in stabilizing partial melts in the Earth’s mantle. However, despite decades of experimental studies on the roles of these two volatile species in affecting mantle melting, […]