About
89
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Introduction
I take a stand for diversity and anti-racism in academia, in the field of earth sciences in particular, where inclusive behaviors and policies have remained mostly inexistent.
I work on the origin and dynamic of volatiles in Earth.
Over the past decade, i've contributed to chemical geodynamics, core formation, and cosmochemistry. I'm also interested in hydrothermalism and i dabble in the arts of clumped isotopes.
Skills and Expertise
Additional affiliations
February 2019 - present
June 2017 - May 2019
Position
- PostDoc Position
Description
- I was the panorama postdoc - Worked there on methane and nitrogen isotopologues in hydrothermal systems
November 2015 - April 2017
Position
- PostDoc Position
Description
- I contributed to the developement of the high-precision Se isotope systematic for chondrites and basalts
Publications
Publications (89)
Methane clumped isotope signatures of abiogenesis may be diagnostic of the origin of methane on Earth and other planetary bodies. We performed synthesis of abiogenic methane in hydrothermal conditions between 130 and 300°C and determined δ¹³C, δD, Δ¹³CH3D, and Δ¹²CH2D2. The experiments were performed by heating water in the presence of Fe⁰ powder a...
Subduction redistributes elements between Earth's principal geochemical reservoirs, modifying the chemical composition of Earth's mantle, crust, atmosphere, and hydrosphere, and consequently having an impact on the evolution of life itself. Subduction of surface material that has been geochemically modified by low-temperature processes leads to min...
Identification of methane origins remains a challenging work as current diagnostic signals are often not sufficient to resolve individual formation and post‐formation processes. To address such a knowledge gap in a tectonically active and fragmented terrain, samples from mud volcanoes, gas seeps, and springs distributed along structural features on...
Background: Editorial board members of academic journals are often considered gatekeepers of knowledge and role models for the community. Editorial boards should have sufficiently diverse backgrounds to facilitate the publication of manuscripts with a wide range of research paradigms, methods, and cultural perspectives.
Objectives: This study crit...
Background: Members of editorial boards of academic journals are often considered gatekeepers of knowledge and role models for the academic community. Editorial boards should be sufficiently diverse in the background of their members to facilitate publishing manuscripts representing a wide range of research paradigms, methods, and cultural perspect...
Microbial methane oxidation - or methanotrophy - is a key control of the global methane budget on Earth, and perhaps in other planetary systems. Here, we explore the potential role of mass-18 isotopologues of methane, expressed as Δ¹³CH3D and Δ¹²CH2D2 values, in tracking both aerobic and anaerobic methanotrophy in nature. We examine two well docume...
The composition the atmosphere of Venus results from the integration of many processes entering into play over the entire geological history of the planet. Determining the elemental abundances and isotopic ratios of noble gases (He, Ne, Ar, Kr, Xe) and stable isotopes (H, C, N, O, S) in the Venus atmosphere is a high priority scientific target sinc...
Under modern oxidising Earth surface conditions, dehydrated subducted slabs show Mo isotope compositions as low as δ 98/95 Mo = −1.5 ‰, compared to the depleted mantle δ 98/95 Mo = −0.2 ‰. Such light Mo isotope compositions reflect the redox-dependent aqueous mobility of isotopically heavy Mo associated with slab dehydration. Here we analysed basal...
The composition the atmosphere of Venus results from the integration of many processes entering into play over the entire geological history of the planet. Determining the elemental abundances and isotopic ratios of noble gases (He, Ne, Ar, Kr, Xe) and stable isotopes (H, C, N, O, S) in the Venus atmosphere is a high priority scientific target sinc...
Background: Editorial board members of academic journals are often considered gatekeepers of knowledge and role models for the community. Editorial boards should have sufficiently diverse backgrounds to facilitate the publication of manuscripts with a wide range of research paradigms, methods, and cultural perspectives.Objectives: This study critic...
Volcanic rocks erupted among Pitcairn seamounts sample a mantle plume that exhibits an extreme Enriched Mantle-1 signature. The origin of this peculiar mantle endmember remains contentious, and could involve the recycling of marine sediments of Archean or Proterozoic ages, delaminated units from the lower continental crust, or metasomatized peridot...
Plate tectonics is thought to be a major driver of volatile redistribution on Earth. The budget of nitrogen in Earth's mantle has been suggested to be almost entirely surface-derived. Recycling would contribute nitrogen with relatively heavy ¹⁵N/¹⁴N isotope ratios to Earth's mantle. This could explain why the Earth's mantle ¹⁵N/¹⁴N isotope ratio is...
The development of high-resolution gas source mass spectrometry has permitted entirely new types of measurements of multiply-substituted isotopologues in gas species of geochemical significance. Here, we present recent advances afforded by measurements of ¹⁵N¹⁵N in natural samples, together with ¹⁴N¹⁴N and ¹⁵N¹⁴N. We show that the abundance of the...
This paper explores the unusual sulphide–graphite association of a selection of Beni Bousera garnet clinopyroxenites that initially equilibrated within the diamond stability field. Compared with common graphite-free garnet pyroxenites analysed so far, these rocks display tenfold S enrichment with concentrations up to 5550 μg g–1. Fe–Ni–Cu sulphides...
In hyperalkaline (pH>10) fluids that have participated in low‐temperature (<150°C) serpentinization reactions, the dominant form of C is often methane (CH4), but the origin of this CH4 is uncertain. To assess CH4 origin in serpentinite aquifers within the Samail Ophiolite, Oman, we determined fluid chemical compositions, analyzed taxonomic profiles...
How much nitrogen and light noble gases are recycled in modern subduction zones is unclear. Fumaroles act as a means for passive degassing in arcs. They receive variable contributions of volatiles from arc magmas, themselves sourced from the mantle wedge. The gas compositions reflect the extent of volatile enrichment in sub-arc mantle sources and c...
In addition to high concentrations of CH4 and H2, abundant dissolved N2 is found in subsurface fracture fluids in Precambrian cratons around the world. These fracture fluids have hydrogeological isolation times on order of thousands to millions and even billions of years. Assessing the sources and sinks of N2 and related (bio)geochemical processes...
Supplementary Fig. S1. Selenium cycle in marine environment.
Talk is available here -> https://www.youtube.com/watch?v=2e2sf7-dzcY
Basalts from the Samoan volcanoes sample contributions from all of the classical mantle endmembers, including extreme EM II and high ³He/⁴He components, as well as dilute contributions from the HIMU, EM I, and DM components. Here, we present multiple sulfur isotope data on sulfide extracted from subaerial and submarine whole rocks (N = 16) associat...
Volatile elements (water, carbon, nitrogen, sulfur, halogens, and noble gases) played an essential role in the secular evolution of the solid Earth and emergence of life. Here we provide an overview of Earth's volatile inventories and describe the mechanisms by which volatiles are conveyed between Earth's surface and mantle reservoirs, via subducti...
“Knowledge belongs to humanity, and is the torch which illuminates the world.” – Louis Pasteur
Find here - https://2021.goldschmidt.info/goldschmidt/2021/meetingapp.cgi/Paper/7356
The measurement of methane clumped isotopologues (Δ13CH3D and Δ12CH2D2) allows exploring isotope bond ordering within methane molecules, and may reveal equilibrium temperatures. Whether such temperature reflects the formation or re-equilibration temperature of the methane is not well understood, but would have critical implications for the use of m...
In the current era of rapid climate change, accurate characterization of climate-relevant gas dynamics – namely production, consumption, and net emissions – is required for all biomes, especially those ecosystems most susceptible to the impact of change. Marine environments include regions that act as net sources or sinks for numerous climate-activ...
Mangaia, an ocean island in the Cook‐Austral volcanic chain, is the type locality for the HIMU mantle reservoir and has also been shown to exhibit evidence for recycled sulfur with anomalous δ³⁴S and Δ³³S that has been attributed an Archean origin. Here we report bulk S‐isotope data from sulfide inclusions in olivine and pyroxene phenocrysts from o...
Oxygenation of Earth's oceans and atmosphere through time has consequences for subducted surface signatures that are now stored in the mantle. Here, we report significant mass-dependent selenium isotope variations in modern hot spot-influenced oceanic lavas. These variations are correlated with tracers of mantle source enrichment, which can only be...
The sulfur isotope budget of Martian regolith breccia (NWA 7533) has been addressed from conventional fluorination bulk rock analyses and ion microprobe in situ analyses. The bulk rock analyses yield 865 ± 50 ppm S in agreement with LA‐ICP‐MS analyses. These new data support previous estimates of 80% S loss resulting from terrestrial weathering of...
Deep-sea hydrothermal fluids are often enriched in carbon dioxide, methane, and hydrogen. Methane effuses from metal-rich black smokers such as the Rainbow hydrothermal field, at temperatures higher than 200 °C. At the Lost City field, CH4 emanates from alkaline fluids at < 100 °C. The abundance of the rare, mass-18 CH4 isotopologues, ¹³CH3D and ¹²...
Methane generated by microorganisms is most often depleted in the doubly substituted isotopologue ¹²CH2D2 relative to the stochastic reference distribution. To constrain the controls on depleted Δ¹²CH2D2 values, we experimentally isolated the root cause with microorganisms that produce methane from methylphosphonate via the C-P lyase pathway. This...
Nitrogen is the main constituent of the Earth’s atmosphere, but its provenance in the Earth’s mantle remains uncertain. The relative contribution of primordial nitrogen inherited during the Earth’s accretion versus that subducted from the Earth’s surface is unclear1–6. Here we show that the mantle may have retained remnants of such primordial nitro...
Understanding present-day mantle heterogeneity is key to understanding the geochemical evolution of our planet. The Samoan islands are the type locality for the Enriched Mantle (II) reservoir that is thought to be produced from the subduction and recycling of marine sediment from upper continental crust. In addition to hosting extreme radiogenic is...
Silicon and Mg in differentiated rocky bodies exhibit heavy isotope enrichments that have been attributed to evaporation of partially or entirely molten planetesimals. We evaluate the mechanisms of planetesimal evaporation in the early solar system and the conditions that controlled attendant isotope fractionations. Energy balance at the surface of...
Anaerobic oxidation of methane (AOM) is a significant but poorly constrained biological sink in the global carbon cycle. While several studies estimate AOM is responsible for consuming ~80-90% produced in marine sediments, its role in curbing the CH4 atmospheric flux in terrestrial freshwater systems, particularly the deep continental biosphere, is...
Silicon and Mg in differentiated rocky bodies exhibit heavy isotope enrichments that have been attributed to evaporation of partially or entirely molten planetesimals. We evaluate the mechanisms of planetesimal evaporation in the early solar system and the conditions that controlled attendant isotope fractionations.
Energy balance at the surface of...
The selenium stable isotope system emerges as a new potential tracer of volatile origin and evolution of the terrestrial planets. Accurate determination of the mantle Se isotope composition requires an assessment of Se isotopic behavior in magmatic processes and potential variations across all mantle reservoirs. Here we report the first high-precis...
The assimilation of sulfate by Martian melts could explain the highly oxidized state of some Martian nakhlite meteorites, such as those paired with MIL 03346 (MIL 090030, MIL 090032, and MIL 090136). Here, a combination of new sulfur isotope data, mineral composition and abundance data, and consideration of mineral textures is used to link assimila...
This study reports the quadruple sulfur isotope composition of troilite nodules from Main Group Pallasites. Values range from −0.23‰ to 0.34‰ (average = 0.03 ± 0.17‰ S.D.) in δ³⁴S and 0.008‰ to 0.025‰ (average = 0.018 ± 0.006‰ S.D.) in Δ³³S and −0.38 to −0.01 (average = −0.17 ± 0.11‰ S.D.) in Δ³⁶S. The variance of these analyses is comparable to es...
The redox-sensitive, chalcophile and volatile Se stable isotope system offers new perspectives to investigate the origin and evolution of terrestrial volatiles and the roles of magmatic and recycling processes in the development of the redox contrast between Earth's reservoirs. Selenium isotope systematics become more robust in a well-constrained p...
Element transfer from the solar nebular gas to solids occurred either through direct condensation or via heterogeneous reactions between gaseous molecules and previously condensed solid matter. The precursors of altered sulfides observed in chondrites are for example attributed to reactions between gaseous hydrogen sulfide and metallic iron grains....
The use of chlorine stable isotopes (³⁵Cl and ³⁷Cl) can help to constrain natural processes that involve chlorine species with different oxidation states. Theoretical studies based on thermodynamic and quantum mechanical approaches predict large isotope fractionation during redox reactions but to date, these reactions have not been studied experime...
The isotopic signature of the chalcophile, redox-sensitive and moderately volatile element Se in geological materials may offer valuable new insights into the origin and evolution of volatiles in planetary systems. Here, we report a new method for Se isotope determination of low Se containing samples relevant to the Earth's mantle reservoir. We pre...
We have investigated the quadruple sulfur isotopic composition of inorganic sulfur-bearing phases from 13 carbonaceous chondrites of CM type. Our samples include 4 falls and 9 Antarctic finds. We extracted sulfur from sulfides, sulfates, and elemental sulfur (S⁰) from all samples. On average, we recover a bulk sulfur (S) content of 2.11±0.39 wt.% S...
Seismic tomography models reveal two large low shear velocity provinces (LLSVPs) that identify large-scale variations in temperature and composition in the deep mantle. Other characteristics include elevated density, elevated bulk sound speed, and sharp boundaries. We show that properties of LLSVPs can be explained by the presence of small quantiti...
http://www.hou.usra.edu/meetings/lpsc2016/pdf/2344.pdf
The Earth’s mantle displays a subchondritic 34S/32S ratio. Sulfur is a moderately siderophile element (i.e. iron-loving), and its partitioning into the Earth’s core may have left such a distinctive isotope composition on the terrestrial mantle. In order to constrain the sulfur isotope fractionation occurring during core–mantle differentiation, high...
Significance
This investigation focuses on the sulfur isotopic compositions of magmatically differentiated meteorites, the oldest igneous rocks in our solar system. We present evidence of anomalous ³³ S depletions in a group of differentiated iron meteorites, along with ³³ S enrichments in several other groups. The complementary positive and negati...
