About

Marc Hirschmann is a professor in the Department of Earth and Environmental Sciences at the University of Minnesota. His research employs high pressure and high temperature experiments, along with analytical and theoretical tools, to understand melting, mass transfer, and differentiation in planetary interiors. His areas of focus include the role of lithologic heterogeneity in basalt source regions, cycling and storage of volatiles such as hydrogen, carbon, nitrogen, and sulfur in planetary interiors, and the delivery and loss processes of these volatiles during the early accretion and differentiation of terrestrial planets. He also investigates redox processes in both modern and early planetary environments. His recent and current research projects include studies of the acquisition and loss of volatiles during planetary formation, interactions between volatiles and redox processes in magma oceans, Fe3+ partitioning during basalt formation, redox processes in Martian magmatism, and the incorporation of hydrogen in lunar materials. His work employs experimental devices and analytical tools such as electron microprobe, FTIR, SIMS, XANES, Mossbauer spectroscopy, EBSD, and LA-ICP-MS. Hirschmann is also involved in undergraduate research opportunities in planetary science.

Research topics

• Astrobiology
• Geology
• Physics
• Computer Security
• Chemistry
• Astronomy
• Computer Science
• Sociology
• Social Science
• Psychoanalysis
• Physical chemistry
• Composite material
• Psychology
• Geochemistry
• Biology
• Mineralogy
• Materials science
• Earth science
• Data science

Selected publications

• Carbon from Interstellar Clouds to Habitable Worlds

  ArXiv.org · 2026-02-10

  articleOpen access

  Carbon is an essential element for a habitable world. Inner (r < 3 au) disk planetary carbon compositions are strongly influenced by supply and survival of carbonaceous solids. Here we trace the journey of carbon from the interstellar medium to the processes leading to planet formation. The review highlights the following central aspects: -Organics forming in evolved star envelopes are supplemented by aromatic molecules forming in the dense ISM to represent the seeds of (hydro)carbon supply through pervasive pebble drift to rocky planets and sub-Neptune cores. -Within the protoplanetary disk the sharp gradient in the C/Si content of Solar System bodies and mineral geochemistry outlines a tale of carbon loss from pebbles to within planetesimals and planets, and from planetary atmospheres. -Within two planet formation paradigms (pebble and planetesimal accretion) a range of planetary carbon content is possible that is strongly influenced by early (< 0.5 Myr) formation of a pressure bump that titrates drift. Overall, it is unlikely that the carbon architecture of our Solar System applies to all systems. In the absence of giant planets, carbon-rich rocky worlds and sub-Neptunes may be common. We outline observations that support their presence and discuss habitability of terrestrial worlds.

  PublisherOA PDF

• Soot Planets Instead of Water Worlds

  The Astrophysical Journal Letters · 2026-01-20 · 5 citations

  preprintOpen access

  Abstract Some low-density exoplanets are thought to be water-rich worlds that formed beyond the snow line of their protoplanetary disk, possibly accreting coequal portions of rock and water. However, the compositions of bodies within the solar system and the stability of volatile-rich solids in accretionary disks suggest that a planet rich in water should also acquire as much as 40% refractory organic carbon (“soot”). This would reduce the water mass fraction well below 50%, making the composition of these planets similar to those of solar system comets. Here we show that soot-rich planets, with or without water, can account for the low average densities of exoplanets that were previously attributed to a binary combination of rock and water. Formed in locations beyond the soot and/or snow lines in disks, these planets are likely common in our galaxy and already observed by JWST. The surfaces and interiors of soot-rich planets will be influenced by the chemical and physical properties of carbonaceous phases, and the atmospheres of such planets may contain plentiful methane and other hydrocarbons, with implications for photochemical haze generation and habitability.

  PublisherDOI

• Ferric iron stabilization at deep magma ocean conditions

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-30

  otherOpen access

  Fe2O3 produced in a deep magma ocean in equilibrium with core-destined alloy sets the early redox budget and atmospheric composition of terrestrial planets. Previous experiments (≤28 GPa) and first-principles calculations indicate that a deep terrestrial magma ocean produces appreciable Fe3+, but predict Fe3+/ΣFe that conflict by an order of magnitude. We present Fe3+/ΣFe of glasses quenched from melts equilibrated with Fe-alloy at 38-71 GPa, 3600-4400 K, analyzed by synchrotron Mössbauer spectroscopy. These indicate Fe3+/ΣFe of 0.056-0.112 in a terrestrial magma ocean with mean alloy-silicate equilibration pressures of 28-53 GPa, producing sufficient Fe2O3 to account for the modern bulk silicate Earth redox budget and surficial conditions near or more oxidizing than the iron-wüstite buffer, which would stabilize a primitive CO- and H2O- rich atmosphere.

  PublisherDOI

• Ferric iron stabilization at deep magma ocean conditions

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-30

  otherOpen access

  Fe2O3 produced in a deep magma ocean in equilibrium with core-destined alloy sets the early redox budget and atmospheric composition of terrestrial planets. Previous experiments (≤28 GPa) and first-principles calculations indicate that a deep terrestrial magma ocean produces appreciable Fe3+, but predict Fe3+/ΣFe that conflict by an order of magnitude. We present Fe3+/ΣFe of glasses quenched from melts equilibrated with Fe-alloy at 38-71 GPa, 3600-4400 K, analyzed by synchrotron Mössbauer spectroscopy. These indicate Fe3+/ΣFe of 0.056-0.112 in a terrestrial magma ocean with mean alloy-silicate equilibration pressures of 28-53 GPa, producing sufficient Fe2O3 to account for the modern bulk silicate Earth redox budget and surficial conditions near or more oxidizing than the iron-wüstite buffer, which would stabilize a primitive CO- and H2O- rich atmosphere.

  PublisherDOI

• Carbon from Interstellar Clouds to Habitable Worlds

  Open MIND · 2026-02-10

  preprint

  Carbon is an essential element for a habitable world. Inner (r &lt; 3 au) disk planetary carbon compositions are strongly influenced by supply and survival of carbonaceous solids. Here we trace the journey of carbon from the interstellar medium to the processes leading to planet formation. The review highlights the following central aspects: -Organics forming in evolved star envelopes are supplemented by aromatic molecules forming in the dense ISM to represent the seeds of (hydro)carbon supply through pervasive pebble drift to rocky planets and sub-Neptune cores. -Within the protoplanetary disk the sharp gradient in the C/Si content of Solar System bodies and mineral geochemistry outlines a tale of carbon loss from pebbles to within planetesimals and planets, and from planetary atmospheres. -Within two planet formation paradigms (pebble and planetesimal accretion) a range of planetary carbon content is possible that is strongly influenced by early (&lt; 0.5 Myr) formation of a pressure bump that titrates drift. Overall, it is unlikely that the carbon architecture of our Solar System applies to all systems. In the absence of giant planets, carbon-rich rocky worlds and sub-Neptunes may be common. We outline observations that support their presence and discuss habitability of terrestrial worlds.

  DOI

• Ferric iron stabilization at deep magma ocean conditions

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-30

  otherOpen access

  Fe2O3 produced in a deep magma ocean in equilibrium with core-destined alloy sets the early redox budget and atmospheric composition of terrestrial planets. Previous experiments (≤28 GPa) and first-principles calculations indicate that a deep terrestrial magma ocean produces appreciable Fe3+, but predict Fe3+/ΣFe that conflict by an order of magnitude. We present Fe3+/ΣFe of glasses quenched from melts equilibrated with Fe-alloy at 38-71 GPa, 3600-4400 K, analyzed by synchrotron Mössbauer spectroscopy. These indicate Fe3+/ΣFe of 0.056-0.112 in a terrestrial magma ocean with mean alloy-silicate equilibration pressures of 28-53 GPa, producing sufficient Fe2O3 to account for the modern bulk silicate Earth redox budget and surficial conditions near or more oxidizing than the iron-wüstite buffer, which would stabilize a primitive CO- and H2O- rich atmosphere.

  PublisherDOI

• Ferric iron stabilization at deep magma ocean conditions

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-30

  otherOpen access

  Fe2O3 produced in a deep magma ocean in equilibrium with core-destined alloy sets the early redox budget and atmospheric composition of terrestrial planets. Previous experiments (≤28 GPa) and first-principles calculations indicate that a deep terrestrial magma ocean produces appreciable Fe3+, but predict Fe3+/ΣFe that conflict by an order of magnitude. We present Fe3+/ΣFe of glasses quenched from melts equilibrated with Fe-alloy at 38-71 GPa, 3600-4400 K, analyzed by synchrotron Mössbauer spectroscopy. These indicate Fe3+/ΣFe of 0.056-0.112 in a terrestrial magma ocean with mean alloy-silicate equilibration pressures of 28-53 GPa, producing sufficient Fe2O3 to account for the modern bulk silicate Earth redox budget and surficial conditions near or more oxidizing than the iron-wüstite buffer, which would stabilize a primitive CO- and H2O- rich atmosphere.

  PublisherDOI

• Controls on Iron-Redox State in Martian Magmas Quantified by Mössbauer Spectroscopy, Colorimetric Wet Chemistry, and XANES Spectroscopy

  2025-04-25 · 1 citations

  preprintOpen accessSenior author

  To elucidate the relationship between oxygen fugacities (fO2) recorded in martian basalts and redox processes in the martian interior, superliquidus 100-kPa furnace experiments on a composition similar to Humphrey (Adirondack basalt) were conducted at variable fO2 and temperature. Quenched glasses were analyzed by EPMA, Mössbauer spectroscopy, colorimetric wet chemistry, and microbeam X-ray absorption near edge structure (XANES) spectroscopy. The experiments reveal Mössbauer and wet chemical determinations of silicate glass Fe3+/FeT agreeing within uncertainty, supporting the accuracy of extended-Voigt-based fitting of Mössbauer spectra when recoil-free fraction is considered. Fe3+/FeT ratios determined from Mössbauer spectroscopy from Humphrey and previously studied martian-relevant glass compositions are combined to calibrate models that characterize the relationship between Fe3+/FeT, fO2, temperature, and composition in martian silicate liquids. The models demonstrate, similar to previously investigated silicate liquids, that the correlation between and logfO2 in martian magmas has a slope less than the value (0.25) expected if ferric and ferrous iron oxide mixed ideally. Martian magma Fe3+/FeT ratios are more temperature-sensitive compared to non-martian compositions, suggesting that temperature variations may contribute to comparatively large fO2 variations in martian basalt. The models are applied to demonstrate that the Fe3+/FeT increases required to explain multiple-log unit changes in fO2 in shergottite magma would not increase terrestrial magma fO2 as effectively. To aid in future investigation of martian magma redox, a XANES technique that allows for non-destructive, microanalytical characterization of Fe3+/FeT in natural martian materials and martian-relevant experiments is introduced.

  PublisherOA PDFDOI

• Ferric iron stabilization at deep magma ocean conditions

  DRYAD · 2024-09-12

  datasetOpen access

  Fe2O3 produced in a deep magma ocean in equilibrium with core-destined alloy sets the early redox budget and atmospheric composition of terrestrial planets. Previous experiments (≤28 GPa) and first-principles calculations indicate that a deep terrestrial magma ocean produces appreciable Fe3+, but predict Fe3+/ΣFe that conflict by an order of magnitude. We present Fe3+/ΣFe of glasses quenched from melts equilibrated with Fe-alloy at 38-71 GPa, 3600-4400 K, analyzed by synchrotron Mössbauer spectroscopy. These indicate Fe3+/ΣFe of 0.056-0.112 in a terrestrial magma ocean with mean alloy-silicate equilibration pressures of 28-53 GPa, producing sufficient Fe2O3 to account for the modern bulk silicate Earth redox budget and surficial conditions near or more oxidizing than the iron-wüstite buffer, which would stabilize a primitive CO- and H2O- rich atmosphere.

  PublisherDOI

• Ferric iron stabilization at deep magma ocean conditions

  Science Advances · 2024-10-16 · 14 citations

  articleOpen access

  Fe 2 O 3 produced in a deep magma ocean in equilibrium with core-destined alloy sets the early redox budget and atmospheric composition of terrestrial planets. Previous experiments (≤28 gigapascals) and first-principles calculations indicate that a deep terrestrial magma ocean produces appreciable Fe 3+ but predict Fe 3+ /ΣFe ratios that conflict by an order of magnitude. We present Fe 3+ /ΣFe of glasses quenched from melts equilibrated with Fe alloy at 38 to 71 gigapascals, 3600 to 4400 kelvin, analyzed by synchrotron Mössbauer spectroscopy. These indicate Fe 3+ /ΣFe of 0.056 to 0.112 in a terrestrial magma ocean with mean alloy-silicate equilibration pressures of 28 to 53 gigapascals, producing sufficient Fe 2 O 3 to account for the modern bulk silicate Earth redox budget and surficial conditions near or more oxidizing than the iron-wüstite buffer, which would stabilize a primitive CO- and H 2 O-rich atmosphere.

  PublisherDOI

Recent grants

• CSEDI: Integrated Study of H2O in the mantle

  NSF · $760k · 2012–2017

• CSEDI:Collaborative Research: Experimental and SIMS investigation of H2O storage capacity of the mantle

  NSF · $211k · 2005–2007

• REU Site: Fluids in the Earth from Surface to Core

  NSF · $296k · 2003–2007

• ABR: Studies of Partial Melting of the Mantle and Deep Earth Volatile Cycles

  NSF · $355k · 2014–2019

• Near Solidus Partial Melting of Garnet Peridotite and the Origin of Alkali Olivine Basalt

  NSF · $417k · 2010–2014

Frequent coauthors

• A. C. Withers

  University of Bayreuth

  58 shared

• Rajdeep Dasgupta

  Rice University

  31 shared

• Tetsu Kogiso

  Kyoto University

  18 shared

• Cyril Aubaud

  Université Paris Cité

  17 shared

• Edward M. Stolper

  16 shared

• M. S. Ghiorso

  OFM Research (United States)

  16 shared

• J. L. Mosenfelder

  Planetary Science Institute

  13 shared

• Avishek Rudra

  University of Minnesota

  13 shared