¹BruceFegleyJr,¹Katharina Lodders,²Nathan S.Jacobson
Geochemistry [Chemie der Erde] (in Press) Link to Article [https://doi.org/10.1016/j.chemer.2019.125594]
¹Planetary Chemistry Laboratory, Dept. of Earth & Planetary Sciences and McDonnell Center for the Space Sciences, Washington University, St. Louis, MO 63130, USA
²Materials Division, NASA Glenn Research Center, MS106-1, 21000 Brookpark Road, Cleveland, OH 44135, USA
Copyright Elsevier

We review some issues relevant to volatile element chemistry during accretion of the Earth with an emphasis on historical development of ideas during the past century and on issues we think are important. These ideas and issues include the following: (1) whether or not the Earth accreted hot and the geochemical evidence for high temperatures during its formation, (2) some chemical consequences of the Earth’s formation before dissipation of solar nebular gas, (3) the building blocks of the Earth, (4) the composition of the Earth and its lithophile volatility trend, (5) chemistry of silicate vapor and steam atmospheres during Earth’s formation, (6) vapor – melt partitioning and possible loss of volatile elements, (7) insights from hot rocky extrasolar planets. We include tabulated chemical kinetic data for high-temperature elementary reactions in silicate vapor and steam atmospheres. We finish with a summary of the known and unknown issues along with suggestions for future work.

^1,2M.Martinot,³J.Flahaut,⁴S.Besse,²C.Quantin-Nataf,³W.van Westrenen
Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2020.113747]
¹Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
²Université Lyon 1, ENS-Lyon, CNRS, UMR 5276 LGL-TPE, F-69622, Villeurbanne, France
³Centre de Recherches Pétrographiques et Géochimiques, CNRS/Université de Lorraine F-54500, Vandoeuvre-lès-Nancy, France
⁴European Space Astronomy Centre, P.O. Box 78, 28691 Villanueva de la Canada, Madrid, Spain
Copyright Elsevier

Spectroscopic data from the Moon Mineralogy Mapper (M3) instrument are used to study the mineralogy of the central peak or peak ring of 75 craters located in the lunar anorthositic Feldspathic Highlands Terrane (FHT-a), as defined by Jolliff et al. (2000). The thickness of South-Pole Aitken (SPA) ejecta at the location of the selected craters is estimated. Crustal thickness models are used with empirical cratering equations to estimate the depth of origin of the material excavated in the studied central peaks, and its distance to the crust-mantle interface. The goal of this survey is to study the composition of the FHT-a crust, and the extent of its potential lateral and vertical heterogeneities. High-Calcium Pyroxene (HCP) and featureless spectra are mostly detected throughout the entire FHT-a, whereas the number of pure plagioclase detections is small. No relationship between the central peak composition and the distance to SPA or the depth within the SPA ejecta is observed. The SPA ejecta material cannot be spectrally distinguished from crustal material. We interpret the paucity of plagioclase spectra in the FHT-a, which contrasts with more frequent plagioclase detections in the central peaks of craters sampling the crust in younger lunar terranes using identical spectroscopic techniques Martinot et al. (2018b), as a possible effect of terrane maturation, or of mixing with mafic components that mask their signature in the visible near-infrared. Overall, the FHT-a appears homogeneous laterally. However, data hint at a pyroxene compositional change with increasing depth, from high-calcium content in the upper crust towards less calcic compositions with increasing depth, which is consistent with prior studies of the architecture of the lunar crust.

^1,3Matthew J.Genge,²Matthias Van Ginneken,³Martin D.Suttle
Planetary and Space Science (in Press) Link to Article [https://doi.org/10.1016/j.pss.2020.104900]
¹Department of Earth Science and Engineering, Imperial College London, Exhibition Road, London, SW7 2AZ, UK
²Department of Physics, University of Kent, Canterbury, Kent, UK
³Department of Earth Sciences, The Natural History Museum, Cromwell Road, London, SW7 2BD, UK

We currently do not have a copyright agreement with this publisher and cannot display the abstract here