M. R. Lee

M. R. Lee
University of Glasgow | UofG · School of Geographical and Earth Sciences

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303
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Publications

Publications (303)
Article
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The Martian nakhlite meteorites, which represent multiple events that belong to a single magma source region represent a key opportunity to study the evolution of Martian petrogenesis. Here 16 of the 26 identified nakhlite specimens are studied using coupled electron backscatter diffraction (EBSD) and emplacement end-member calculations. EBSD was u...
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Deformation is a near ubiquitous process that is observed within nearly all naturally forming rocks. Electron backscatter diffraction (EBSD) is a technique that enables slip-systems (a form of plastic deformation) to be inferred from intra-crystalline misorientations at a comparable scale to representative CPO analysis (≥300 crystals for the nakhli...
Conference Paper
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Recent studies such as [1] suggest that some Al-rich chondrules could have formed from the melting of Ameboid Olivine Aggregates (AOA) and types B and C Calcium-Aluminium-rich Inclusion (CAI) precursors. Al-rich chondrules have intermediate compositions between ferromagnesian chondrules and plagioclase-rich CAIs [2]. It is within Al-rich chondrules...
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The isotopic composition of water in Earth’s oceans is challenging to recreate using a plausible mixture of known extraterrestrial sources such as asteroids—an additional isotopically light reservoir is required. The Sun’s solar wind could provide an answer to balance Earth’s water budget. We used atom probe tomography to directly observe an averag...
Conference Paper
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Compound-chondrule CAIs (CCCAIs) are rare occurrences within carbonaceous chondrites, having only been reported sporadically within most major groups (CO [1], CV [2], and CH [3]) and only once reported within another CM chondrite, Paris (CM2.7) [4]. These rare objects have been described as CAIs enclosing chondrules [5] [4] or as chondrules enclosi...
Conference Paper
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Chondrule size variation between the different chondrite classes and within different chondrite groups has long been recognized, with chondrule sizes used as a key criterion for class and group level classification [1,2]. Despite this, chondrules can differ in size within individual chondrite groups including the CMs, whose chondrules are commonly...
Article
Understanding the quantity and isotopic composition of water that has been delivered to Earth over its history is crucial for models our planet’s evolution, and predicting habitability across the solar system. Here we have used stepwise pyrolysis to measure the hydrogen inventory of CM carbonaceous chondrites, which are likely to have been a major...
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Both the Chicxulub and Boltysh impact events are associated with the K-Pg boundary. While Chicxulub is firmly linked to the end-Cretaceous mass extinction, the temporal relationship of the ~24-km-diameter Boltysh impact to these events is uncertain, although it is thought to have occurred 2 to 5 ka before the mass extinction. Here, we conduct the f...
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Hydrous phyllosilicate minerals, including the serpentine subgroup, are likely to be major constituents of material that will be bought back to Earth by missions to Mars and to primitive asteroids Ryugu and Bennu. Small quantities (< 60 g) of micrometre sized, internally heterogeneous material will be available for study, requiring minimally destru...
Conference Paper
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With the successful return of the JAXA Hayabusa2 sample collection from the Ryugu asteroid, the study of extra-terrestrial carbonaceous samples is now, more than ever, relevant in answering one of planetary science’s most prominent question: the origin of Earth’s water [1, 2]. Carbonaceous chon-drites have a relatively high water content (~ 9 wt%;...
Conference Paper
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Introduction: Carbonates are ubiquitous in the CM carbonaceous chondrites and are believed to have formed from low temperature aqueous alteration on the CM parent body in the first 5 Myr after solar system formation [1-2]. The presence and mineralogy of carbonates is included by [3] in their classification scheme describing the extent of aqueous al...
Conference Paper
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The CM carbonaceous chondrites represent the most pristine solar system material available for study and therefore, provide an excellent opportunity to improve our understanding of the evolution of solids in the Solar System. Chondrules and the fine-grained rims (FGR’s) which surround them represent ~20 vol%. of the CM chondrites [1] and can provid...
Article
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The CM carbonaceous chondrites provide unique insights into the composition of the protoplanetary disk, and the accretion and geological history of their parent C‐complex asteroid(s). Of the hundreds of CMs that are available for study, the majority are finds and so may have been compromised by terrestrial weathering. Nineteen falls have been recov...
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The practical limitations inherent to human and robotic planetary exploration necessitate the development of specific protocols and methods. This non-standard approach requires testing and validation phases in order to optimize instrumental setups and improve data interpretation; this can occur prior to, during, or even after a mission. Flight inst...
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The upcoming Mars Sample Return (MSR) mission aims to deliver small quantities of Martian rocks to the Earth. Investigating these precious samples requires the development and application of techniques that can extract the greatest amount of high quality data from the minimum sample volume, thereby maximising science return from MSR. Atom probe tom...
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The CM carbonaceous chondrites have all been aqueously altered, and some of them were subsequently heated in a parent body environment. Here we have sought to understand the impact of short duration heating on a highly aqueously altered CM through laboratory experiments on Allan Hills (ALH) 83100. Unheated ALH 83100 contains 83 volume per cent serp...
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The Tissint Martian meteorite is an unusual depleted olivine‐phyric shergottite, reportedly sourced from a mantle‐derived melt within a deep magma chamber. Here, we report major and trace element data for Tissint olivine and pyroxene, and use these data to provide new insights into the dynamics of the Tissint magma chamber. The presence of irregula...
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Plagioclase feldspar is one of the most common rock‐forming minerals on the surfaces of the Earth and other terrestrial planetary bodies, where it has been exposed to the ubiquitous process of hypervelocity impact. However, the response of plagioclase to shock metamorphism remains poorly understood. In particular, constraining the initiation and pr...
Article
San Salvador (Bahamas) is a carbonate island with dozens of flank margin caves formed in the phreatic zone by fresh seawater mixing within the freshwater lens. These caves have no direct connection with the sea, and form at or close to the tidally influenced fluctuating water table. After sea-level fall, in their subaerial parts caves are enlarged...
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The age of the Gow Lake impact structure (Saskatchewan, Canada) is poorly constrained, with previous estimates ranging from 100 to 250 Ma. Using a combination of step-heating and UV laser in situ ⁴⁰Ar/³⁹Ar analyses we have sought to understand the ⁴⁰Ar/³⁹Ar systematics of this small impact crater and obtain a more precise and accurate age. This str...
Conference Paper
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The origin of Earth's water is one of the most prominent questions of planetary science. Ambitious projects such as the JAXA Hayabusa2 and the NASA OSIRIS-REx sample collection missions aim to help provide answers to this question. The targeted asteroids, Ryugu and Bennu, respectively, are thought to be of similar compositions to carbonaceous chond...
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Meteorite Hills (MET) 01075 is unique among the CM carbonaceous chondrites in containing the feldspathoid mineral sodalite, and hence it may provide valuable evidence for a nebular or parent body process that has not been previously recorded by this meteorite group. MET 01075 is composed of aqueously altered chondrules and calcium‐ and aluminum‐ric...
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Recent dynamical models of Solar System evolution and isotope studies of rock-forming elements in meteorites have suggested that volatile-rich asteroids formed in the outer Solar System beyond Jupiter’s orbit, despite being currently located in the main asteroid belt1–4. The ambient temperature under which asteroids formed is a crucial diagnostic t...
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Nakhlite meteorites are ~1.4 to 1.3 Ga old igneous rocks, aqueously altered on Mars ~630 Ma ago. We test the theory that water-rock interaction was impact driven. Electron backscatter diffraction demonstrates that the meteorites Miller Range 03346 and Lafayette were heterogeneously deformed, leading to localized regions of brecciation, plastic defo...
Conference Paper
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This is an overview of the results of our ongoing research aiming at better understanding of the formation and survival of impact coesite - a debated issue in impact cratering and shock metamorphism studies.
Article
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Coesite, a high-pressure silica polymorph, is a diagnostic indicator of impact cratering in quartz-bearing target rocks. The formation mechanism of coesite during hypervelocity impacts has been debated since its discovery in impact rocks in the 1960s. Electron diffraction analysis coupled with scanning electron microscopy and Raman spectroscopy of...
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A carbon‐rich melt fragment from the Gardnos impact structure has been studied for a better understanding of the preservation and structural form(s) of carbon that have been processed by impact melting. The carbon was analyzed in situ in its original petrographic context within the melt fragment, using high‐resolution techniques including focused i...
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Lewis Cliff (LEW) 85311 is classified as a Mighei-like (CM) carbonaceous chondrite, yet it has some unusual properties that highlight an unrealised diversity within the CMs, and also questions how many parent bodies are sampled by the group. This meteorite is composed of rimmed chondrules, chondrule fragments and refractory inclusions that are set...
Conference Paper
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Volatile abundances in amphibole and apatite can be used to estimate the volatile content of their parental melts and mantle source regions in Martian meteorites. It has been suggested that the Martian parental melts which produce the shergottites had water/chlorine and water/fluorine ratios of ~0.418, similar to terrestrial MORB ratios. Amphibole...
Preprint
Recent dynamical models of Solar System evolution and isotope studies of rock-forming elements in meteorites have suggested that volatile-rich asteroids formed in the outer Solar System beyond Jupiter's orbit, despite being currently located in the main asteroid belt. The ambient temperature under which asteroids formed is a crucial diagnostic to p...
Article
In order to validate calculated ages of the Martian crust we require precise radiometric dates from igneous rocks where their provenance on the Martian surface is known. Martian meteorites have been dated precisely and quantitatively, but the launch sites are currently unknown. Inferring the formation environment of a correlated suite of Martian me...
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https://doi.org/10.1016/j.gca.2019.05.025 Martian lava flows likely acquired S-rich material from the regolith during their emplacement on the planet’s surface. We investigated five of the twenty known nakhlites (Nakhla, Lafayette, Miller Range (MIL) 090032, Yamato 000593, and Yamato 000749) to determine whether these lavas show evidence of regoli...
Article
We report the discovery of a partially altered microchondrule within a fine-grained micrometeorite. This object is circular, <10μm in diameter, and has a cryptocrystalline texture, internal zonation, and a thin S-bearing rim. These features imply a period of postaccretion parent body aqueous alteration, in which the former glassy igneous texture wa...
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Protoplanetary disks are dust-rich structures around young stars. The crystalline and amorphous materials contained within these disks are variably thermally processed and accreted to make bodies of a wide range of sizes and compositions, depending on the heliocentric distance of formation. The chondritic meteorites are fragments of relatively smal...
Conference Paper
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Drill core petrography from the Rochechouart impact structure.
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Conference Paper
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Scanning and transmission electron microscopy observations on shocked silica mineral grains from the Australasian tektite/microtektite strewn field suggest that coesite crystals form directly in contact with quartz grains through a subsolidus reconstructive transformation. This finding is in contrast with the current mainstream view, which consider...
Conference Paper
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The objective of the H2020-funded EURO-CARES project (grant agreement n° 640190) was to create a roadmap for the implementation of a European Extraterrestrial Sample Curation Facility (ESCF) that would be suitable for the curation of samples from all possible return missions likely over the next few decades, i.e. from the Moon, asteroids and Mars....
Conference Paper
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The sulphur isotopic characteristics of Martian meteorites, including mass independent fractiona-tion, suggest that magmatic assimilation of sulphur occurred throughout the planet's geological history. Sulphur isotope ratios can be fractionated by three main processes: hydrothermal, photochemical, and biological. Large isotopic fractionations of δ...
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The nakhlite meteorites characteristically contain iddingsite, a hydrous iron–magnesium silicate that formed by aqueous alteration on Mars. Iddingsite is most abundant in Northwest Africa (NWA) 817, and alteration products in this meteorite also have the lowest deuterium/hydrogen ratio of any nakhlite. Taken together, these distinctive properties c...
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Martian meteorite Northwest Africa (NWA) 7034 and its paired stones are the only brecciated regolith samples from Mars with compositions that are representative of the average martian crust. These samples therefore provide a unique opportunity to constrain the processes of metamorphism and alteration in the martian crust, which we have investigated...
Conference Paper
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First results from the Rochechouart impact crater drilling campaign.
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The oxygen isotope composition of well-preserved trilobite eye calcite, retaining its original optical properties, represents a possible source of information on Paleozoic sea temperatures. Species of the epipelagic telephinid genera Carolinites and Opipeuterella from strata of Early to Middle Ordovician age in Spitsbergen and Australia were analyz...
Conference Paper
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Geochemical and geophysical data suggest that the martian mantle retained heat from Mars formation, and that it could still be actively convecting [e.g., 1]. Here we try to infer thermodynamical information related to martian mantle activity via mineralogical data acquired from olivine and pyroxene in the Tissint martian meteorite, with a crystalli...
Conference Paper
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Introduction: Geochemical and geophysical data suggest that the martian mantle retained heat from Mars formation, and that it could still be actively convecting [e.g., 1]. Here we try to infer thermodynamical information related to martian mantle activity via mineralogical data acquired from olivine and pyroxene in the Tissint martian meteorite. Ti...
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The shergottites are the largest group of Martian meteorites, and the only group that has not been found to contain definitive evidence of Martian aqueous alteration. Given recent reports of current liquid water at the surface of Mars, this study aimed to investigate in detail the possibility of Martian phyllosilicate within shergottite Dhofar 019....
Conference Paper
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Introduction: The Rochechouart impact structure [1], dated at ~203 Ma (recalc.) [2], is among the most accessible large impact sites on Earth [3-4]. Only the center of the crater is still preserved [1, 3-4]. The initial diameter estimated between 30-50 km, remains undetermined [3-4]. The full sequence of crater deposits, including fine grained impa...
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Mars hosts the solar system’s largest volcanoes. Although their size and impact crater density indicate continued activity over billions of years, their formation rates are poorly understood. Here we quantify the growth rate of a Martian volcano by ⁴⁰Ar/³⁹Ar and cosmogenic exposure dating of six nakhlites, meteorites that were ejected from Mars by...