パーセバランスに搭載されたスーパーカムにより、ジェゼロクレーターの岩石組成が解明された The SuperCam instrument onboard Perseverance helped researchers better understand rock composition of the Jezero Crater
2022-08-26 アメリカ・ロスアラモス国立研究所(LANL)
SuperCamは、レーザー誘起ブレークダウン分光法（LIBS）と呼ばれる技術で、集束した赤外線レーザービームを使って岩石の表面から塵や物質を除去する。5ナノ秒のパルスによるエネルギーバーストがフラッシュを作り、その光学スペクトル（特定の色）から、約25フィート離れたターゲットの元素の化学的性質が明らかになる。
＜関連情報＞
火星ジェゼロクレーターにおける組成・密度成層火成岩地形 Compositionally and density stratified igneous terrain in Jezero crater, Mars
Roger C. Wiens,Arya Udry ,Olivier Beyssac,Cathy Quantin-Nataf ,Nicolas Mangold ,Agnès Cousin ,Lucia Mandon ,Tanja Bosak ,Olivier Forni ,Scott M. McLennan,Violaine Sautter,Adrian Brown ,Karim Benzerara ,Jeffrey R. Johnson ,Lisa Mayhew ,Sylvestre Maurice ,Ryan B. Anderson,Samuel M. Clegg,Larry Crumpler ,Travis S. J. Gabriel ,Patrick Gasda,James Hall ,Briony H. N. Horgan ,Linda Kah,Carey LegettIV ,Juan Manuel Madariaga ,Pierre-Yves Meslin ,Ann M. Ollila ,Francois Poulet,Clement Royer ,Shiv K. Sharma ,Sandra Siljeström ,Justin I. Simon,Tayro E. Acosta-Maeda,Cesar Alvarez-Llamas,S. Michael Angel,Gorka Arana ,Pierre Beck ,Sylvain Bernard ,Tanguy Bertrand ,Bruno Bousquet,Kepa Castro ,Baptiste Chide ,Elise Clavé ,Ed Cloutis ,Stephanie Connell,Erwin Dehouck ,Gilles Dromart,Woodward Fischer ,Thierry Fouchet ,Raymond Francis ,Jens Frydenvang ,Olivier Gasnault,Erin Gibbons ,Sanjeev Gupta ,Elisabeth M. Hausrath ,Xavier Jacob ,Hemani Kalucha,Evan Kelly ,Elise Knutsen ,Nina Lanza ,Javier Laserna ,Jeremie Lasue ,Stéphane Le Mouélic ,Richard Leveille,Guillermo Lopez Reyes ,Ralph Lorenz ,Jose Antonio Manrique ,Jesus Martinez-Frias ,Tim McConnochie ,Noureddine Melikechi,David Mimoun ,Franck Montmessin,Javier Moros,Naomi Murdoch ,Paolo Pilleri ,Cedric Pilorget ,Patrick Pinet,William Rapin ,Fernando Rull ,Susanne Schröder ,David L. Shuster ,Rebecca J. Smith ,Alexander E. Stott ,Jesse Tarnas ,Nathalie Turenne ,Marco Veneranda ,David S. Vogt,Benjamin P. Weiss,Peter Willis ,Kathryn M. Stack ,Kenneth H. Williford,Kenneth A. Farley ,The SuperCam Team
Science Advances Published:25 Aug 2022
DOI: 10.1126/sciadv.abo3399
Abstract
Before Perseverance, Jezero crater’s floor was variably hypothesized to have a lacustrine, lava, volcanic airfall, or aeolian origin. SuperCam observations in the first 286 Mars days on Mars revealed a volcanic and intrusive terrain with compositional and density stratification. The dominant lithology along the traverse is basaltic, with plagioclase enrichment in stratigraphically higher locations. Stratigraphically lower, layered rocks are richer in normative pyroxene. The lowest observed unit has the highest inferred density and is olivine-rich with coarse (1.5 millimeters) euhedral, relatively unweathered grains, suggesting a cumulate origin. This is the first martian cumulate and shows similarities to martian meteorites, which also express olivine disequilibrium. Alteration materials including carbonates, sulfates, perchlorates, hydrated silicates, and iron oxides are pervasive but low in abundance, suggesting relatively brief lacustrine conditions. Orbital observations link the Jezero floor lithology to the broader Nili-Syrtis region, suggesting that density-driven compositional stratification is a regional characteristic.
