Cargando…

Composition, Stratigraphy, and Geological History of the Noachian Basement Surrounding the Isidis Impact Basin

The western part of the Isidis basin structure hosts a well-characterized Early Noachian to Amazonian stratigraphy. The Noachian Basement comprises its oldest exposed rocks (Early to Mid-Noachian) and was previously considered a single low-Ca pyroxenes (LCP)- and Fe/Mg-smectite-bearing unit. Here, w...

Descripción completa

Detalles Bibliográficos
Autores principales: Scheller, Eva L., Ehlmann, Bethany L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8378244/
https://www.ncbi.nlm.nih.gov/pubmed/34422533
http://dx.doi.org/10.1029/2019je006190
_version_ 1783740800734068736
author Scheller, Eva L.
Ehlmann, Bethany L.
author_facet Scheller, Eva L.
Ehlmann, Bethany L.
author_sort Scheller, Eva L.
collection PubMed
description The western part of the Isidis basin structure hosts a well-characterized Early Noachian to Amazonian stratigraphy. The Noachian Basement comprises its oldest exposed rocks (Early to Mid-Noachian) and was previously considered a single low-Ca pyroxenes (LCP)- and Fe/Mg-smectite-bearing unit. Here, we divide the Noachian Basement Group into five distinct geological units (Stratified Basement Unit, Blue Fractured Unit, Mixed Lithology Plains Unit, LCP-bearing Plateaus Unit, and Fe/Mg-smectite-bearing Mounds Unit), two geomorphological features (megabreccia and ridges), and a mineral deposit (kaolinite-bearing bright materials), based on geomorphology, spectral characteristics, and stratigraphic relationships. Megabreccia contain four different pre-Isidis lithologies, possibly including deeper crust or mantle materials, formed through mass wasting associated with transient crater collapse during Isidis basin formation. The Fe/Mg-smectite-bearing Stratified Basement Unit and LCP-bearing Blue Fractured Unit likewise represent pre-Isidis units within the Noachian Basement Group. Multiple Fe/Mg-smectite-bearing geological units with different stratigraphic positions and younger kaolinite-bearing bright materials indicate several aqueous alteration episodes of different ages and styles. Units with slight changes in pyroxene spectral properties suggest a transition from low-Ca pyroxene-containing materials to those with higher proportions of pyroxenes higher in Ca and/or glass that could be related to different impact and/or igneous processes, or provenance. This long history of Noachian and potentially Pre-Noachian geological processes, including impact basin formation, aqueous alteration, and multiple igneous and sedimentary petrogeneses, records changing ancient Mars environmental conditions. All units defined by this study are available 20 km outside of Jezero crater for in situ analysis and sampling during a potential extended mission scenario for the Mars 2020 rover.
format Online
Article
Text
id pubmed-8378244
institution National Center for Biotechnology Information
language English
publishDate 2020
record_format MEDLINE/PubMed
spelling pubmed-83782442021-08-20 Composition, Stratigraphy, and Geological History of the Noachian Basement Surrounding the Isidis Impact Basin Scheller, Eva L. Ehlmann, Bethany L. J Geophys Res Planets Article The western part of the Isidis basin structure hosts a well-characterized Early Noachian to Amazonian stratigraphy. The Noachian Basement comprises its oldest exposed rocks (Early to Mid-Noachian) and was previously considered a single low-Ca pyroxenes (LCP)- and Fe/Mg-smectite-bearing unit. Here, we divide the Noachian Basement Group into five distinct geological units (Stratified Basement Unit, Blue Fractured Unit, Mixed Lithology Plains Unit, LCP-bearing Plateaus Unit, and Fe/Mg-smectite-bearing Mounds Unit), two geomorphological features (megabreccia and ridges), and a mineral deposit (kaolinite-bearing bright materials), based on geomorphology, spectral characteristics, and stratigraphic relationships. Megabreccia contain four different pre-Isidis lithologies, possibly including deeper crust or mantle materials, formed through mass wasting associated with transient crater collapse during Isidis basin formation. The Fe/Mg-smectite-bearing Stratified Basement Unit and LCP-bearing Blue Fractured Unit likewise represent pre-Isidis units within the Noachian Basement Group. Multiple Fe/Mg-smectite-bearing geological units with different stratigraphic positions and younger kaolinite-bearing bright materials indicate several aqueous alteration episodes of different ages and styles. Units with slight changes in pyroxene spectral properties suggest a transition from low-Ca pyroxene-containing materials to those with higher proportions of pyroxenes higher in Ca and/or glass that could be related to different impact and/or igneous processes, or provenance. This long history of Noachian and potentially Pre-Noachian geological processes, including impact basin formation, aqueous alteration, and multiple igneous and sedimentary petrogeneses, records changing ancient Mars environmental conditions. All units defined by this study are available 20 km outside of Jezero crater for in situ analysis and sampling during a potential extended mission scenario for the Mars 2020 rover. 2020-03-10 2020-07 /pmc/articles/PMC8378244/ /pubmed/34422533 http://dx.doi.org/10.1029/2019je006190 Text en https://creativecommons.org/licenses/by/4.0/This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Article
Scheller, Eva L.
Ehlmann, Bethany L.
Composition, Stratigraphy, and Geological History of the Noachian Basement Surrounding the Isidis Impact Basin
title Composition, Stratigraphy, and Geological History of the Noachian Basement Surrounding the Isidis Impact Basin
title_full Composition, Stratigraphy, and Geological History of the Noachian Basement Surrounding the Isidis Impact Basin
title_fullStr Composition, Stratigraphy, and Geological History of the Noachian Basement Surrounding the Isidis Impact Basin
title_full_unstemmed Composition, Stratigraphy, and Geological History of the Noachian Basement Surrounding the Isidis Impact Basin
title_short Composition, Stratigraphy, and Geological History of the Noachian Basement Surrounding the Isidis Impact Basin
title_sort composition, stratigraphy, and geological history of the noachian basement surrounding the isidis impact basin
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8378244/
https://www.ncbi.nlm.nih.gov/pubmed/34422533
http://dx.doi.org/10.1029/2019je006190
work_keys_str_mv AT schellereval compositionstratigraphyandgeologicalhistoryofthenoachianbasementsurroundingtheisidisimpactbasin
AT ehlmannbethanyl compositionstratigraphyandgeologicalhistoryofthenoachianbasementsurroundingtheisidisimpactbasin