Entries by Rajdeep Dasgupta

The Astrophysical Journal: The effect of a strong pressure bump in the Sun’s natal disk: Terrestrial planet formation via planetesimal accretion rather than pebble accretion

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The effect of a strong pressure bump in the Sun’s natal disk: Terrestrial planet formation via planetesimal accretion rather than pebble accretion André Izidoro, Bertram Bitsch, Rajdeep Dasgupta Abstract Mass-independent isotopic anomalies of carbonaceous and noncarbonaceous meteorites show a clear dichotomy suggesting an efficient separation of the inner and outer solar system. Observations show that […]

EPSL: Assessing the presence of volatile-bearing mineral phases in the cratonic mantle as a possible cause of mid-lithospheric discontinuities

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Authors: Sriparna Saha, Ye Peng, Rajdeep Dasgupta, Mainak Mookherjee, Karen M. Fischer Abstract: A number of possible hypotheses have been proposed to explain the origin of mid-lithospheric discontinuities (MLDs), typically characterized by ∼2-6% reductions in seismic shear wave velocity (Vs) at depths of 60 km to ∼150 km in the cratonic sub-continental lithospheric mantle (SCLM). […]

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

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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

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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

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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

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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

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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

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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

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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

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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 […]