^1,2Jaramillo, E.A.,³Royle, S.H.,^4,5Claire, M.W.,^1,3Kounaves, S.P.,³Sephton, M.A.
Geophysical Research Letters 46, 3090-3098 Link to Article [DOI: 10.1029/2018GL081335]
¹Department of Chemistry, Tufts University, Medford, MA, United States
²Now at Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
³Department of Earth Science and Engineering, Imperial College London, London, United Kingdom
⁴School of Earth and Environmental Sciences and Centre for Exoplanet Science, University of St. Andrews, Saint Andrews, United Kingdom
⁵Blue Marble Space Institute of Science, Seattle, WA, United States

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

¹N. M. Curran,^1,2K. H. Joy,³J. F. Snape,¹J. F. Pernet‐Fisher,¹J. D. Gilmour,⁴A. A. Nemchin,³M. J. Whitehouse,¹R. Burgess
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13295]

¹School of Earth and Environmental Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL UK
²NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland, 20771 USA
³Department of Geosciences, Swedish Museum of Natural History, SE‐104 05 Stockholm, Sweden
⁴Department of Applied Geology, Curtin University, Perth, Western Australia, 6845 Australia
Published by arrangement with John Wiley & Sons

Miller Range (MIL) 13317 is a heterogeneous basalt‐bearing lunar regolith breccia that provides insights into the early magmatic history of the Moon. MIL 13317 is formed from a mixture of material with clasts having an affinity to Apollo ferroan anorthosites and basaltic volcanic rocks. Noble gas data indicate that MIL 13317 was consolidated into a breccia between 2610 ± 780 Ma and 1570 ± 470 Ma where it experienced a complex near‐surface irradiation history for ~835 ± 84 Myr, at an average depth of ~30 cm. The fusion crust has an intermediate composition (Al₂O₃ 15.9 wt%; FeO 12.3 wt%) with an added incompatible trace element (Th 5.4 ppm) chemical component. Taking the fusion crust to be indicative of the bulk sample composition, this implies that MIL 13317 originated from a regolith that is associated with a mare‐highland boundary that is KREEP‐rich (i.e., K, rare earth elements, and P). A comparison of bulk chemical data from MIL 13317 with remote sensing data from the Lunar Prospector orbiter suggests that MIL 13317 likely originated from the northwest region of Oceanus Procellarum, east of Mare Nubium, or at the eastern edge of Mare Frigoris. All these potential source areas are on the near side of the Moon, indicating a close association with the Procellarum KREEP Terrane. Basalt clasts in MIL 13317 are from a very low‐Ti to low‐Ti (between 0.14 and 0.32 wt%) source region. The similar mineral fractionation trends of the different basalt clasts in the sample suggest they are comagmatic in origin. Zircon‐bearing phases and Ca‐phosphate grains in basalt clasts and matrix grains yield ²⁰⁷Pb/²⁰⁶Pb ages between 4344 ± 4 and 4333 ± 5 Ma. These ancient ²⁰⁷Pb/²⁰⁶Pb ages indicate that the meteorite has sampled a range of Pre‐Nectarian volcanic rocks that are poorly represented in the Apollo, Luna, and lunar meteorite collections. As such, MIL 13317 adds to the growing evidence that basaltic volcanic activity on the Moon started as early as ~4340 Ma, before the main period of lunar mare basalt volcanism at ~3850 Ma.

¹Marcos Alberto Rodrigues Vasconcelos,¹Fernanda Farias Rocha,²Alvaro Penteado Crósta,^3,4Kai Wünnemann,³Nicole Güldemeister,²Emilson Pereira Leite,³Júlio César Ferreira,^3,5Wolf Uwe Reimold
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13298]
¹Department of Geophysics, Instituto de Geociências, Universidade Federal da Bahia, Salvador, Brazil
²Instituto de Geociências, Universidade Estadual de Campinas, R. Carlos Gomes 250, 13083‐855 Campinas, Sao Paulo, Brazil
³Museum für Naturkunde—Leibniz‐Institute for Evolution and Biodiversity Science, Invalidenstrasse 43, 10115 Berlin, Germany
⁴Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
⁵Laboratory of Geochronology, Instituto de Geociências, Universidade de Brasília, 10910‐900 Brasília, Federal District, Brazil
Published by arrangement with John Wiley & Sons

We present the outcomes of simulations of the formation of the Vista Alegre impact structure, Paraná Basin, Brazil. The target comprised a thick sequence of volcanic rocks of predominantly basaltic composition of the Serra Geral Formation that had been deposited on top of sedimentary rocks (sandstones) of the Pirambóia/Botucatu formations. The cratering process was modeled using the iSALE shock physics code. Our best‐fit model suggests that (1) the crater was originally ~10 km in size; (2) it was formed in ~115 s by a stony projectile of 1000 m in diameter, for an assumed impact velocity of 12 km s−1; (3) target rocks underwent a peak pressure of ~20 GPa, in agreement with previous petrographic investigations of shock deformation. Furthermore, the model points out that the sedimentary strata below the layer of volcanic rocks were raised by ~650 meters at the central part of the crater, which resulted in the current partial exposure of the sandstones at the surface. The outcomes of our modeling suggest that parameters like cohesion and strength of the target rocks, after shock compression, determined the final morphology of the crater, especially the absence of a topographically prominent central peak. Finally, the results of the numerical modeling are roughly in agreement with gravity data over the structure, in particular with respect to the presence of the uplifted sedimentary strata, which are responsible for a low gravity signature at the center of the structure.