Chemistry of fracture-filling raised ridges in Yellowknife Bay, Gale Crater: Window into past aqueous activity and habitability on Mars

被引：66

作者：

Leveille, Richard J. ^{[1
,2
]}

Bridges, John ^{[3
]}

Wiens, Roger C. ^{[4
]}

Mangold, Nicolas ^{[5
]}

Cousin, Agnes ^{[4
]}

Lanza, Nina ^{[4
]}

Forni, Olivier ^{[6
,7
]}

Ollila, Ann ^{[8
]}

Grotzinger, John ^{[9
]}

Clegg, Samuel ^{[4
]}

Siebach, Kirsten ^{[9
]}

Berger, Gilles ^{[6
,7
]}

Clark, Ben ^{[10
]}

Fabre, Cecile ^{[11
]}

Anderson, Ryan ^{[12
]}

Gasnault, Olivier ^{[6
,7
]}

Blaney, Diana ^{[13
]}

Deflores, Lauren ^{[13
]}

Leshin, Laurie ^{[14
]}

Maurice, Sylvestre ^{[6
,7
]}

Newsom, Horton ^{[8
]}

机构：

[1] Canadian Space Agcy, St Hubert, PQ, Canada

[2] McGill Univ, Dept Nat Resource Sci, Montreal, PQ, Canada

[3] Univ Leicester, Dept Phys & Astron, Space Res Ctr, Leicester LE1 7RH, Leics, England

[4] Los Alamos Natl Lab, Los Alamos, NM USA

[5] Univ Nantes, Lab Planetol & Geodynam Nantes, Nantes, France

[6] Univ Toulouse, UPS OMP, IRAP, Toulouse, France

[7] CNRS, IRAP, Toulouse, France

[8] Univ New Mexico, Inst Meteorit, Albuquerque, NM 87131 USA

[9] CALTECH, Lab Planetol & Geodynam Nantes, Pasadena, CA 91125 USA

[10] Space Sci Inst, Boulder, CO USA

[11] Univ Lorraine, GeoRessources UMR CNRS, Nancy, France

[12] US Geol Survey, Flagstaff, AZ 86001 USA

[13] CALTECH, Jet Prop Lab, Pasadena, CA USA

[14] Rensselaer Polytech Inst, Troy, NY USA

来源：

JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS | 2014年 / 119卷 / 11期

关键词：

Mars; diagenesis; mudstone; smectite; magnesium; LIBS; INDUCED BREAKDOWN SPECTROSCOPY; DEPTH-PROFILE ANALYSIS; CLAY MINERAL FORMATION; CEMENT STRATIGRAPHY; MERIDIANI-PLANUM; SAPONITE; CHEMCAM; HISTORY; TARGETS; DIAGENESIS;

D O I：

10.1002/2014JE004620

中图分类号：

P3 [地球物理学]; P59 [地球化学];

学科分类号：

0708 ; 070902 ;

摘要：

The ChemCam instrument package on the Curiosity rover was used to characterize distinctive raised ridges in the Sheepbed mudstone, Yellowknife Bay formation, Gale Crater. The multilayered, fracture-filling ridges are more resistant to erosion than the Sheepbed mudstone rock in which they occur. The bulk average composition of the raised ridges is enriched in MgO by 1.2-1.7 times (average of 8.3-11.4 wt %; single-shot maximum of 17.0 wt %) over that of the mudstone. Al2O3 is anticorrelated with MgO, while Li is somewhat enriched where MgO is highest. Some ridges show a variation in composition with different layers on a submillimeter scale. In particular, the McGrath target shows similar high-MgO resistant outer layers and a low-MgO, less resistant inner layer. This is consistent with the interpretation that the raised ridges are isopachous fracture-filling cements with a stratigraphy that likely reveals changes in fluid composition or depositional conditions over time. Overall, the average composition of the raised ridges is close to that of a Mg- and Fe-rich smectite, or saponite, which may also be the main clay mineral constituent of the host mudstone. These analyses provide evidence of diagenesis and aqueous activity in the early postdepositional history of the Yellowknife Bay formation, consistent with a low salinity to brackish fluid at near-neutral or slightly alkaline pH. The fluids that circulated through the fractures likely interacted with the Sheepbed mudstone and (or) other stratigraphically adjacent rock units of basaltic composition and leached Mg from them preferentially.

引用

页码：2398 / 2415

页数：18