干旱区生态环境知识资源中心(Arid): Multiple mineral horizons in layered outcrops at Mawrth Vallis, Mars, signify changing geochemical environments on early Mars

Arid

DOI	10.1016/j.icarus.2020.113634
	Multiple mineral horizons in layered outcrops at Mawrth Vallis, Mars, signify changing geochemical environments on early Mars
	Bishop, Janice L.1,2; Gross, Christoph 2; Danielsen, Jacob 1,3; Parente, Mario 4; Murchie, Scott L.5; Horgan, Briony 6; Wray, James J.7; Viviano, Christina 5; Seelos, Frank P.5
通讯作者	Bishop, Janice L.
来源期刊	ICARUS
ISSN	0019-1035
EISSN	1090-2643
出版年	2020
卷号	341
英文摘要	Refined calibrations of CRISM images are enabling identification of smaller deposits of unique aqueous materials on Mars that reveal changing environmental conditions at the region surrounding Mawrth Vallis. Through characterization of these clay-sulfate assemblages and their association with the layered, phyllosilicate units of this region, more details of the aqueous geochemical history can be gleaned. A stratigraphy including five distinct mineral horizons is mapped using compositional data from CRISM over CTX and HRSC imagery across 100s of km and from CRISM over HiRISE imagery across 100s of meters. Transitions in mineralogic units were characterized using visible/near-infrared (VNIR) spectral properties and surface morphology. We identified and characterized complex doublet type spectral signatures with two bands between 2.2 and 2.3 mu m at one stratigraphic horizon. Based on comparisons with terrestrial sites, the spectral doublet unit described here may reflect the remnants of a salty, evaporative period that existed on Mars during the transition from formation of Fe-rich phyllosilicates to Al-rich phyllosilicates. Layered outcrops observed at Mawrth Vallis are thicker than in other altered regions of Mars, but may represent processes that were more widespread in wet regions of the planet during its early history. The aqueous geochemical environments supporting the outcrops observed here include: (i) the formation of Fe3+-rich smectites in a warm and wet environment, (ii) overlain by a thin ferrousbearing clay unit that could be associated with heating or reducing conditions, (iii) followed by a transition to salty and/or acidic alteration phases and sulfates (characterized by the spectral doublet shape) in an evaporative setting, (iv) formation of Al-rich phyllosilicates through pedogenesis or acid leaching, and (v) finally persistence of poorly crystalline aluminosilicates marking the end of the warm climate on early Mars. The doublet type units described here are likely composed of clay-sulfate assemblages formed in saline, acidic evaporative environments similar to those found in Western Australia and the Atacama desert. Despite the chemically extreme and variable waters present at these terrestrial, saline lake environments, active ecosystems are present; thus, these doublet type units may mark exciting areas for continued exploration important to astrobiology on Mars.
英文关键词	Mars Mineralogy Spectroscopy Aqueous processes Salt Climate
类型	Article
语种	英语
国家	USA ; Germany
开放获取类型	Green Accepted, hybrid
收录类别	SCI-E
WOS记录号	WOS:000519150100006
WOS关键词	DIOCTAHEDRAL SMECTITES ; EMISSION-SPECTROSCOPY ; MICROBIAL REDUCTION ; SPECTRAL PROPERTIES ; CLAY-MINERALS ; SALINE LAKES ; ACID ; REGION ; SURFACE ; FE
WOS类目	Astronomy & Astrophysics
WOS研究方向	Astronomy & Astrophysics
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/314703
作者单位	1.SETI Inst, Mountain View, CA 94043 USA; 2.Free Univ Berlin, Berlin, Germany; 3.San Jose State Univ, San Jose, CA 95192 USA; 4.Univ Massachusetts, Amherst, MA 01003 USA; 5.Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA; 6.Purdue Univ, W Lafayette, IN 47907 USA; 7.Georgia Inst Technol, Atlanta, GA 30332 USA
推荐引用方式 GB/T 7714	Bishop, Janice L.,Gross, Christoph,Danielsen, Jacob,et al. Multiple mineral horizons in layered outcrops at Mawrth Vallis, Mars, signify changing geochemical environments on early Mars[J],2020,341.
APA	Bishop, Janice L..,Gross, Christoph.,Danielsen, Jacob.,Parente, Mario.,Murchie, Scott L..,...&Seelos, Frank P..(2020).Multiple mineral horizons in layered outcrops at Mawrth Vallis, Mars, signify changing geochemical environments on early Mars.ICARUS,341.
MLA	Bishop, Janice L.,et al."Multiple mineral horizons in layered outcrops at Mawrth Vallis, Mars, signify changing geochemical environments on early Mars".ICARUS 341(2020).