Evolution of a Lake Margin Recorded in the Sutton Island Member of the Murray Formation, Gale Crater, Mars

Abstract

This study uses data from the Mars Science Laboratory Curiosity rover to document the facies of the Sutton Island member of the Murray formation, interpret paleoenvironments, and establish key stratigraphic transitions at Gale crater. Two facies associations were identified: Facies Association 1 (FA1) and Facies Association 2 (FA2). Individual facies in FA1 include planar‐laminated mudstone with minor intervals of planar sandstone, ripple cross‐laminated sandstone, cross‐stratified sandstone, and alternating laminated sandstone and mudstone. Meter‐thick packages of planar‐laminated mudstone in FA1 are interpreted to represent deposition in low‐energy ponded environments along the lake margin. Straight‐ and curve‐crested ripple cross‐laminated facies are interpreted to represent current‐influenced deposition. Cross‐stratified sandstone facies consist of dm‐thick sets that represent deposition in distal channels. Intercalated mm‐scale mudstone and sandstone laminae represent waning flow conditions and possible channel abandonment. Facies in FA1 collectively represent deposition in a distal delta plain. FA2 is comprised of planar‐laminated mudstone with minor sandstone and is interpreted to represent deposition in a lacustrine‐basin setting by suspension settling linked to density flows. FA1 transitions upward into FA2, defining a rapid transgression substantial enough to facilitate the deposition of distal lake facies above delta plain facies. The abrupt transition from FA2 back to FA1 deltaic deposits is suggestive of forced regression. Facies in FA1 and FA2 are consistent with the prevalence of aqueous environments recorded in other Murray formation members and extend our understanding of the dynamic sedimentary processes that characterized ancient lacustrine systems at Gale crater.

Manganese‐Rich Sandstones as an Indicator of Ancient Oxic Lake Water Conditions in Gale Crater, Mars

“…However, this interpretation was based on the larger scale of the outcrops and the intervals of cross stratified sandstones in those outcrops that likely indicate a dune setting (Gwizd et al, 2022). Blocks in Sutton Island are more broken up than in continuous outcrops, making this interpretation more difficult; Gwizd et al (2023) showed that the changes in Sutton Island bedrock likely represent a change in lake water level. The higher portion of Sutton Island likely represents the channel outlet near the shore of the lake (Gwizd et al, 2023).…”

“…Gale's central mound, Aeolis Mons (informally "Mount Sharp"), rises 5 km above the crater floor, Aeolis Palus, and is largely comprised of sedimentary rocks (Fraeman et al, 2016;Malin & Edgett, 2000;Milliken et al, 2010). Gale is interpreted as having hosted a habitable redox-stratified lake or series of lakes in its past based on chemical, mineral, and stratigraphic evidence of hematite and phyllosilicate-bearing fluvial-deltaic deposits and lacustrine mudstones (Edgar et al, 2020;Grotzinger et al, 2014Grotzinger et al, , 2015Gwizd et al, 2022Gwizd et al, , 2023Hurowitz et al, 2017;Vaniman et al, 2014). The Gale lake produced 100s of meters of typically fine-grained thinly laminated lake sediment deposits, collectively named the Murray formation (Edgar et al, 2020;Rivera-Hernández et al, 2020).…”

“…This is interpreted by Edgar et al (2020) as a transition from a marginal lake or lake depositional setting (shallow water levels) to a suspension fall-out lacustrine (deeper, stable water levels) depositional setting. Sutton Island could represent a setting where fluvial channels transported water and sediments into a nearby lake, potentially via isolated pools connected by river channels, facilitating spatially and stratigraphically variable deposition of sand and mudstone (e.g., Gwizd et al, 2022Gwizd et al, , 2023Rapin et al, 2019). Evaporation of these lakes and pools causes the formation of desiccation cracks (Stein et al, 2018).…”

“…Such events produce sedimentary horizons of authigenic Mn oxides, such as in the Baltic Sea (Huckriede & Meischner, 1996). Although a river system is implicated by the delta model (Figure 4; Edgar et al, 2020;Gwizd et al, 2023;Rapin et al, 2019;Rivera-Hernández et al, 2020), and could be a source of freshwater, it is difficult to envision a selective mechanism by which only some sandstones would be sites of preferential Mn oxide precipitation related to periodic oxidation.…”

“…Here, we focus on the strata in the Murray formation below Vera Rubin ridge (VRR), where abundances of the major oxides in the bedrock, including FeO T and CaO, do not vary greatly over the stratigraphic section, but MnO and MgO do vary (Frydenvang et al, 2020). The first member encountered by the rover was Pahrump Hills, which is interpreted as mainly a fine-grained layered mudstone lacustrine deposit (Edgar et al, 2020;Fedo et al, 2017Fedo et al, , 2018Grotzinger et al, 2015;Gwizd et al, 2022Gwizd et al, , 2023Rivera-Hernández et al, 2019Stack et al, 2019). The Hartmann's Valley and Karasberg deposits are interpreted as a mix of lake and lake margins and potentially aeolian deposits (Gwizd et al, 2022).…”