The Distribution of Clay Minerals and Their Impact on Diagenesis in Glen Torridon, Gale Crater, Mars

The Glen Torridon stratigraphic sequence marks the transition from the low energy lacustrine-dominated Murray formation (Mf) (Jura member: Jm) to the more diverse Carolyn Shoemaker formation (CSf) (Knockfarril Hill member: Knockfarril Hill; Glasgow member: Glasgow). This transition defines a change in depositional setting. Alpha Particle X-ray Spectrometer (APXS) results and statistical analysis reveal that the bulk primary geochemistry of Mf targets are broadly in family with CSf targets, but with subtle compositional and diagenetic trends with increasing elevation. APXS results reveal significant compositional differences between Jura_GT and the stratigraphically equivalent Jura on Vera Rubin ridge (Jura_ VRR). The data define two geochemical facies (high-K or high-Mg), with a strong bimodal grain distribution in Jura_GT and Knockfarril Hill. The contact between Knockfarril Hill and Glasgow is marked by abrupt sedimentological changes but a similar composition for both. Away from the contact, the Knockfarril Hill and Glasgow plot discretely, suggesting a zone of common alteration at the transition and/or a gradual transition in provenance with increasing elevation in the Glasgow member. APXS results point to a complex history of diagenesis within Glen Torridon, with increasing diagenesis close to the Basal Siccar Point unconformity on the Greenheugh pediment, and with proximity to the beginning of the clay sulfate transition. Elemental mobility is evident in localized enrichments or depletions in Ca, S, Mn, P, Zn, Ni. The highly altered Hutton interval, in contact with the unconformity on Tower butte, is also identified on Western Butte, indicating that the "interval" was once laterally extensive.

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“…This is in agreement with Rudolph et al. (2022), who identify spectral signatures associated with clay minerals across all three members.…”

Section: Discussionsupporting

confidence: 93%

Statistical Analysis of APXS‐Derived Chemistry of the Clay‐Bearing Glen Torridon Region and Mount Sharp Group, Gale Crater, Mars

et al. 2022

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“…However, bedrock color variations in Sutton Island are less widespread and light toned bedrock does not exhibit the same spectral characteristics as it does on VRR and in Glen Torridon. In addition, in these other areas where hematite dissolution has been proposed, the fluids are thought to have destroyed clay minerals as well (Rampe et al., 2020; Rudolph et al., 2022), which is inconsistent with their apparent persistence in Sutton Island in Mastcam data, and suggests that those fluids never penetrated into Sutton Island bedrock. Finally, as discussed below, the morphology and distribution of diagenetic features of Sutton Island is more consistent with limited flow of late diagenetic fluids, making it less likely that late diagenesis preferentially removed hematite in Sutton Island compared to surrounding intervals.…”

Section: Discussionmentioning

confidence: 99%

“…Alternatively, fine grained crystalline hematite could be absent in much of Sutton Island because it formed initially and was later removed, for example, by diagenetic fluids that remobilized and removed the hematite in parts of Sutton Island. Dissolution of fine‐grained red hematite by reducing or acidic diagenetic fluids has been proposed to have created bleached zones on VRR and in Glen Torridon (Horgan et al., 2020; Rudolph et al., 2022). However, bedrock color variations in Sutton Island are less widespread and light toned bedrock does not exhibit the same spectral characteristics as it does on VRR and in Glen Torridon.…”

Section: Discussionmentioning

confidence: 99%

Mineralogy of a Possible Ancient Lakeshore in the Sutton Island Member of Mt. Sharp, Gale Crater, Mars, From Mastcam Multispectral Images

et al. 2022

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The Curiosity rover on the Mars Science Laboratory mission has found extensive evidence that Gale crater once hosted a habitable lacustrine environment; however, there are remaining questions about the chemistry and duration of the lake and the nature of the climate at the time. In this study, we use Mastcam multispectral data to investigate the mineralogy of the Sutton Island member of the Murray formation, a part of the basal layers of Mt. Sharp, which consists of heterolithic mudstone and sandstone that are distinct from the finely laminated mudstones that dominate much of the Murray. Sutton Island includes at least one instance of desiccation cracks, indicative of subaerial exposure, and uniquely irregular diagenetic features that may be related to local bedrock permeability. These features suggest that Sutton Island experienced a complex history of deposition and diagenesis which may be crucial for understanding changing water‐rock interactions within Gale. We find that most Mastcam bedrock spectra in this region lack the absorptions associated with hematite found throughout the Murray, and instead show deeper absorptions shifted toward longer wavelengths that are more consistent with Fe‐smectites such as nontronite. Elemental chemistry from ChemCam supports this interpretation, as SiO, MgO, Li, and the chemical index of alteration are elevated in this region. Combined with observations of bedrock sedimentology, this suggests that Sutton Island was deposited in a nearshore or low stand environment, and we hypothesize that the clay minerals were produced in this region due to sub‐aerial exposure and weathering in a semi‐arid climate.

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“…The A shift towards stronger S7584 but still shallow BD535 occurs around sol 2750-2800, at an area referred to as the Hutton interval. This interval occurs in the Glasgow member below the Siccar Point unconformity, and it is also associated with a color change in Mastcam color images, as well as a unique chemistry and mineralogy (Dehouck et al, 2022;Rudolph et al, 2022;Thompson et al, 2022;Thorpe et al, 2022). Specifically, the Hutton interval in the Glasgow member is characterized by a decrease in chemical index of alteration (CIA) values, localized enrichments and depletions in mobile elements, and significant amount of cristobalite and opal-CT (Dehouck et al, 2022;O'Connell-Cooper et al, 2022;Thorpe et al, 2022).…”

Section: Glamentioning

confidence: 99%

Compositional Variations in Sedimentary Deposits in Gale Crater as Observed by ChemCam Passive and Active Spectra

Manelski

Sheppard

Fraeman

et al. 2022

Preprint

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During the first 2934 sols of the Curiosity rover’s mission 33,468 passive visible/near-infrared reflectance spectra were taken of the surface by the mast-mounted ChemCam instrument on a range of target types. ChemCam spectra of bedrock targets from the Murray and Carolyn Shoemaker formations on Mt. Sharp were investigated using principal component analysis (PCA) and various spectral parameters including the band depth at 535 nm and the slope between 840 nm and 750 nm. Four endmember spectra were identified. Passive spectra were compared to Laser Induced Breakdown Spectroscopy (LIBS) data to search for correlations between spectral properties and elemental abundances. The correlation coefficient between FeOT reported by LIBS and BD535 from passive spectra was used to search for regions where iron may have been added to the bedrock through oxidation of ferrous-bearing fluids, but no correlations were found. Rocks in the Blunts Point-Sutton Island transition that have unique spectral properties compared to surrounding rocks, that is flat near-infrared (NIR) slopes and weak 535 nm absorptions, are associated with higher Mn and Mg in the LIBS spectra of bedrock. Additionally, calcium-sulfate cements, previously identified by Ca and S enrichments in the LIBS spectra of bedrock, were also shown to be associated with spectral trends seen in Blunts Point. A shift towards steeper near-infrared slope is seen in the Hutton interval, indicative of changing depositional conditions or increased diagenesis.

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The Distribution of Clay Minerals and Their Impact on Diagenesis in Glen Torridon, Gale Crater, Mars

Cited by 14 publications

References 109 publications

Statistical Analysis of APXS‐Derived Chemistry of the Clay‐Bearing Glen Torridon Region and Mount Sharp Group, Gale Crater, Mars

Statistical Analysis of APXS‐Derived Chemistry of the Clay‐Bearing Glen Torridon Region and Mount Sharp Group, Gale Crater, Mars

Mineralogy of a Possible Ancient Lakeshore in the Sutton Island Member of Mt. Sharp, Gale Crater, Mars, From Mastcam Multispectral Images

Compositional Variations in Sedimentary Deposits in Gale Crater as Observed by ChemCam Passive and Active Spectra

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