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The shocking state of apatite and merrillite in shergottite Northwest Africa 5298 and extreme nanoscale chlorine isotope variability revealed by atom probe tomography

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The shocking state of apatite and merrillite in shergottite Northwest Africa 5298 and extreme nanoscale chlorine isotope variability revealed by atom probe tomography. / Darling, James; White, Lee; Kizovski, Tanya; Černok, Ana; Moser, Desmond E.; Tait, Kimberly; Dunlop, Joseph Nicholas; Langelier, Brian; Douglas, James; Zhao, Xuchao; Franchi, Ian; Anand, Mahesh.

In: Geochimica et Cosmochimica Acta, 17.11.2020.

Research output: Contribution to journalArticlepeer-review

Harvard

Darling, J, White, L, Kizovski, T, Černok, A, Moser, DE, Tait, K, Dunlop, JN, Langelier, B, Douglas, J, Zhao, X, Franchi, I & Anand, M 2020, 'The shocking state of apatite and merrillite in shergottite Northwest Africa 5298 and extreme nanoscale chlorine isotope variability revealed by atom probe tomography', Geochimica et Cosmochimica Acta. https://doi.org/10.1016/j.gca.2020.11.007

APA

Darling, J., White, L., Kizovski, T., Černok, A., Moser, D. E., Tait, K., Dunlop, J. N., Langelier, B., Douglas, J., Zhao, X., Franchi, I., & Anand, M. (2020). The shocking state of apatite and merrillite in shergottite Northwest Africa 5298 and extreme nanoscale chlorine isotope variability revealed by atom probe tomography. Geochimica et Cosmochimica Acta. https://doi.org/10.1016/j.gca.2020.11.007

Vancouver

Author

Darling, James ; White, Lee ; Kizovski, Tanya ; Černok, Ana ; Moser, Desmond E. ; Tait, Kimberly ; Dunlop, Joseph Nicholas ; Langelier, Brian ; Douglas, James ; Zhao, Xuchao ; Franchi, Ian ; Anand, Mahesh. / The shocking state of apatite and merrillite in shergottite Northwest Africa 5298 and extreme nanoscale chlorine isotope variability revealed by atom probe tomography. In: Geochimica et Cosmochimica Acta. 2020.

Bibtex

@article{664e147a1307423aa424f5103fef2ceb,
title = "The shocking state of apatite and merrillite in shergottite Northwest Africa 5298 and extreme nanoscale chlorine isotope variability revealed by atom probe tomography",
abstract = "The elemental and chlorine isotope compositions of calcium-phosphate minerals are key recorders of the volatile inventory of Mars, as well as the planet{\textquoteright}s endogenous magmatic and hydrothermal history. Most martian meteorites have clear evidence for exogenous impact-generated deformation and metamorphism, yet the effects of these shock metamorphic processes on chlorine isotopic records contained within calcium phosphates have not been evaluated. Here we test the effects of a single shock metamorphic cycle on chlorine isotope systematics in apatite from the highly shocked, enriched shergottite Northwest Africa (NWA) 5298. Detailed nanostructural (EBSD, Raman and TEM) data reveals a wide range of distributed shock features. These are principally the result of intensive plastic deformation, recrystallization and/or impact melting. These shock features are directly linked with chemical heterogeneities, including crosscutting microscale chlorine-enriched features that are associated with shock melt and iron-rich veins. NanoSIMS chlorine isotope measurements of NWA 5298 apatite reveal a range of δ37Cl values (-3 to 1 ‰; 2σ uncertainties <0.9 ‰) that is almost as large as all previous measurements of basaltic shergottites, and the measured δ37Cl values can be readily linked with different nanostructural states of targeted apatite. High spatial resolution atom probe tomography (APT) data reveal that chlorine-enriched and defect-rich nanoscale boundaries have highly negative δ37Cl values (mean of -15 ± 8 ‰). Our results show that shock metamorphism can have significant effects on chemical and chlorine isotopic records in calcium phosphates, principally as a result of chlorine mobilization during shock melting and recrystallization. Despite this, low-strain apatite domains have been identified by EBSD, and yield a mean δ37Cl value of -0.3 ± 0.6 ‰ that is taken as the best estimate of the primary chlorine isotopic composition of NWA 5298. The combined nanostructural, microscale-chemical and nanoscale APT isotopic approach gives the ability to better isolate and identify endogenous volatile-element records of magmatic and near-surface processes as well as exogenous, shock-related effects.",
keywords = "Meteorite, Mars, Geology, Geochemistry, isotope geochemistry, Apatite, Merrillite, Atom probe tomography, NanoSIMS, EBSD, Scanning electron microscopy, Microstructure, RCUK, STFC, ST/S000291/1, ST/T002239/1, ST/P000657/1, EPSRC, EP/M022803/1, APC-PAID",
author = "James Darling and Lee White and Tanya Kizovski and Ana {\v C}ernok and Moser, {Desmond E.} and Kimberly Tait and Dunlop, {Joseph Nicholas} and Brian Langelier and James Douglas and Xuchao Zhao and Ian Franchi and Mahesh Anand",
note = "12 months embargo. Elsevier.",
year = "2020",
month = nov,
day = "17",
doi = "10.1016/j.gca.2020.11.007",
language = "English",
journal = "Geochimica et Cosmochimica Acta",
issn = "0016-7037",
publisher = "Elsevier Limited",

}

RIS

TY - JOUR

T1 - The shocking state of apatite and merrillite in shergottite Northwest Africa 5298 and extreme nanoscale chlorine isotope variability revealed by atom probe tomography

AU - Darling, James

AU - White, Lee

AU - Kizovski, Tanya

AU - Černok, Ana

AU - Moser, Desmond E.

AU - Tait, Kimberly

AU - Dunlop, Joseph Nicholas

AU - Langelier, Brian

AU - Douglas, James

AU - Zhao, Xuchao

AU - Franchi, Ian

AU - Anand, Mahesh

N1 - 12 months embargo. Elsevier.

PY - 2020/11/17

Y1 - 2020/11/17

N2 - The elemental and chlorine isotope compositions of calcium-phosphate minerals are key recorders of the volatile inventory of Mars, as well as the planet’s endogenous magmatic and hydrothermal history. Most martian meteorites have clear evidence for exogenous impact-generated deformation and metamorphism, yet the effects of these shock metamorphic processes on chlorine isotopic records contained within calcium phosphates have not been evaluated. Here we test the effects of a single shock metamorphic cycle on chlorine isotope systematics in apatite from the highly shocked, enriched shergottite Northwest Africa (NWA) 5298. Detailed nanostructural (EBSD, Raman and TEM) data reveals a wide range of distributed shock features. These are principally the result of intensive plastic deformation, recrystallization and/or impact melting. These shock features are directly linked with chemical heterogeneities, including crosscutting microscale chlorine-enriched features that are associated with shock melt and iron-rich veins. NanoSIMS chlorine isotope measurements of NWA 5298 apatite reveal a range of δ37Cl values (-3 to 1 ‰; 2σ uncertainties <0.9 ‰) that is almost as large as all previous measurements of basaltic shergottites, and the measured δ37Cl values can be readily linked with different nanostructural states of targeted apatite. High spatial resolution atom probe tomography (APT) data reveal that chlorine-enriched and defect-rich nanoscale boundaries have highly negative δ37Cl values (mean of -15 ± 8 ‰). Our results show that shock metamorphism can have significant effects on chemical and chlorine isotopic records in calcium phosphates, principally as a result of chlorine mobilization during shock melting and recrystallization. Despite this, low-strain apatite domains have been identified by EBSD, and yield a mean δ37Cl value of -0.3 ± 0.6 ‰ that is taken as the best estimate of the primary chlorine isotopic composition of NWA 5298. The combined nanostructural, microscale-chemical and nanoscale APT isotopic approach gives the ability to better isolate and identify endogenous volatile-element records of magmatic and near-surface processes as well as exogenous, shock-related effects.

AB - The elemental and chlorine isotope compositions of calcium-phosphate minerals are key recorders of the volatile inventory of Mars, as well as the planet’s endogenous magmatic and hydrothermal history. Most martian meteorites have clear evidence for exogenous impact-generated deformation and metamorphism, yet the effects of these shock metamorphic processes on chlorine isotopic records contained within calcium phosphates have not been evaluated. Here we test the effects of a single shock metamorphic cycle on chlorine isotope systematics in apatite from the highly shocked, enriched shergottite Northwest Africa (NWA) 5298. Detailed nanostructural (EBSD, Raman and TEM) data reveals a wide range of distributed shock features. These are principally the result of intensive plastic deformation, recrystallization and/or impact melting. These shock features are directly linked with chemical heterogeneities, including crosscutting microscale chlorine-enriched features that are associated with shock melt and iron-rich veins. NanoSIMS chlorine isotope measurements of NWA 5298 apatite reveal a range of δ37Cl values (-3 to 1 ‰; 2σ uncertainties <0.9 ‰) that is almost as large as all previous measurements of basaltic shergottites, and the measured δ37Cl values can be readily linked with different nanostructural states of targeted apatite. High spatial resolution atom probe tomography (APT) data reveal that chlorine-enriched and defect-rich nanoscale boundaries have highly negative δ37Cl values (mean of -15 ± 8 ‰). Our results show that shock metamorphism can have significant effects on chemical and chlorine isotopic records in calcium phosphates, principally as a result of chlorine mobilization during shock melting and recrystallization. Despite this, low-strain apatite domains have been identified by EBSD, and yield a mean δ37Cl value of -0.3 ± 0.6 ‰ that is taken as the best estimate of the primary chlorine isotopic composition of NWA 5298. The combined nanostructural, microscale-chemical and nanoscale APT isotopic approach gives the ability to better isolate and identify endogenous volatile-element records of magmatic and near-surface processes as well as exogenous, shock-related effects.

KW - Meteorite

KW - Mars

KW - Geology

KW - Geochemistry

KW - isotope geochemistry

KW - Apatite

KW - Merrillite

KW - Atom probe tomography

KW - NanoSIMS

KW - EBSD

KW - Scanning electron microscopy

KW - Microstructure

KW - RCUK

KW - STFC

KW - ST/S000291/1

KW - ST/T002239/1

KW - ST/P000657/1

KW - EPSRC

KW - EP/M022803/1

KW - APC-PAID

U2 - 10.1016/j.gca.2020.11.007

DO - 10.1016/j.gca.2020.11.007

M3 - Article

JO - Geochimica et Cosmochimica Acta

JF - Geochimica et Cosmochimica Acta

SN - 0016-7037

ER -

ID: 23363912