Juvenile Chemical Sediments and the Long Term Persistence of Water at the Surface of Mars

By N. Tosca, Andrew H. Knoll. 2009

148 citations recorded by the source corpus.

Abstract Chemical sediments and the aqueous alteration products of volcanic rocks clearly indicate the presence of water, at least episodically, at the Martian surface. Compared to similar materials formed on the early Earth, however, Martian deposits are juvenile, or diagenetically under-developed. Here we examine the role of water in facilitating various diagenetic reactions and evaluate the predicted effects of time and temperature for aqueous diagenesis on Mars. Using kinetic formulations based on terrestrial sedimentary geology, we quantify the integrated effects of time and temperature for a range of possible burial and thermal histories of precipitated minerals on Mars. From this, we estimate thresholds beyond which these precipitates should have been converted to the point of non-detection in the presence of water. Surface water has been shown to be at least episodically present in recent times. Nonetheless, the integrated duration of aqueous activity recorded over geologically long intervals by hydrated amorphous silica, smectite clays and Fe-sulfate minerals suggests that where these minerals occur water did not persist much beyond their initial deposition. This geochemical conclusion converges with geomorphologic studies that suggest water limitation during the late Noachian–Hesperian peak of valley formation and a still more limited footprint of water since that time. In addition to documenting the presence of water and its chemical properties, a complete assessment of potentially habitable environments on Mars should address the timescales on which liquid water has persisted and the timing of aqueous episodes relative to major planetary events.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/2ea6503e0ec6e0009e5ba71f942d2a55d6529603

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In Astronomy and Astrophysics

Citations in the corpus

The Sample Analysis at Mars Investigation and Instrument Suite (2012, background): “Diagenesis may gradually convert smectites into mixed-layer clays and ultimately chlorite, so the preservation of smectites over billions of years may strongly constrain the persistence of aqueous fluids (Tosca and Knoll 2009).”
Geologic Constraints on Early Mars Climate (2018, background): “…silica – shows that postNoachian aqueous alteration on Mars could not have been both global and long-lasting (e.g. Osterloo et al. 2010, Stopar et al. 2006, Tosca & Knoll 2009, Elwood-Madden et al. 2009, Ruff & Hamilton 2017, Tosca et al. 2008, Olsen & Rimstidt 2007, McLennan et al. 2019).”
The Climate of Early Mars (2016, background): “Indeed, global analysis of aqueous alteration products on the Martian surface suggests a predominance of juvenile or weakly modified minerals (Tosca & Knoll 2009).”
Heterogeneous distribution of H2O in the Martian interior: Implications for the abundance of H2O in depleted and enriched mantle sources (2016, background): “…hydrologic cycle is still open to debate (Greeley 1987; Karlsson et al. 1992; Squyres and Kasting 1994; Phillips et al. 2001; Craddock and Howard 2002; Treiman 2003; Borg and Drake 2005; Paige 2005; Hurowitz and McLennan 2007; Tosca et al. 2008; Tosca and Knoll 2009; Di Achille and Hynek 2010).”
3D modelling of the early Martian Climate under a denser CO2 atmosphere: Temperatures and CO2 ice clouds. (2012, methodology): “…alteration minerals can still be observed today, although they formed several billion years ago and are easily transformed into othermaterials by, e.g., diagenesis, suggests that water has been very limited on the martian surface from soon after their formation until today (Tosca and Knoll, 2009)).”
Subsurface water and clay mineral formation during the early history of Mars (2011, background): “, and juvenile-clay mineralogy, that is, the persistence of smectite clays, even at great depths rather than their total diagenetic conversion to illite or chlorite phase”