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A Burial History of the Sedimentary Succession Preserved in Aeolis Mons, as Recorded by Fracture Networks at Maria Gordon Notch, Gale Crater, Mars.

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Title: A Burial History of the Sedimentary Succession Preserved in Aeolis Mons, as Recorded by Fracture Networks at Maria Gordon Notch, Gale Crater, Mars.
Authors: Banham, Steven G.1 (AUTHOR) s.banham@imperial.ac.uk, Cosgrove, John W.1 (AUTHOR), Paar, Gerhard2 (AUTHOR), Gupta, Sanjeev1 (AUTHOR), Hughes, Madison N.3 (AUTHOR), Grant, John A.4 (AUTHOR), Mondro, Claire A.5 (AUTHOR), Barnes, Rob1 (AUTHOR), Fraeman, Abigail A.6 (AUTHOR)
Source: Journal of Geophysical Research. Planets. Jul2025, Vol. 130 Issue 7, p1-39. 39p.
Subject Terms: *Hydraulic fracturing, Burial (Geology), Gale Crater (Mars), Diagenesis, Rock deformation, Sequence stratigraphy, Mars (Planet)
Abstract: Fractures in sedimentary rocks preserved within Gale crater record the deformational and burial history of the sediment infill. Fracture geometries and morphology can be used to time other geologic events, such as: compaction, diagenesis, fluid migration, geochemistry, and broader tectonic stresses within a basin. The rover Curiosity acquired images to construct 3D digital outcrop models used for characterization of fracture sets exposed in aeolian strata of the Mirador formation at Maria Gordon notch, identifying four distinct fracture sets. Three fracture sets formed during burial, and one during exhumation. The first group (Sets 1 and 2) consisted of bedding‐parallel and bedding‐bounded vertical fractures associated with early lithification and hydraulic fracturing of the rock as water escaped from isolated pores. Fracture Set 3—Vertical sulfate‐filled fractures—formed after a second episode of diagenesis, as water escaped from deeper within the sedimentary succession. The final fracture set is barren and associated with exhumation of the crater fill. Modeling burial stress suggests that Sets 1 and 2 would form at depths greater than 1 km. The tensile strength of the rocks is generally higher than anticipated due to the absence of shear fractures (faults). Fracture Sets 1–3 demonstrate dewatering of the strata during burial, which continued up until maximum burial at ∼4.7 km. This water was driven toward the surface, providing water for diagenesis and alteration reactions and could have reasonably extended the habitability window within Gale crater. Plain Language Summary: Gale crater contains a mound of sediment that accumulated under a mixture of wet, and then increasingly dry conditions. As lake sediments were buried and lithified, water became trapped in the pore spaces. With increasing burial depth, the pore water pressure increased until it exceeded the tensile strength of the rock, causing fractures to form. Because the confining weight of the overlying rocks was normally greater than the horizontal confining forces, these fractures typically formed in a sub‐vertical orientation. The timing of different fracture sets corresponds to different stages of burial, and the interactions between fractures can be used to time events within the subsurface, such as compaction and lithification of the sediments, the ground water geochemistry, and external tectonic compression on the basin. Fracturing occurred in four stages: three sets formed during burial, associated with dewatering of the accumulated sediment, and the fourth set was associated with the exhumation of Mount Sharp. The dewatering process would drive water upwards into shallower strata, driving diagenesis, and lithification of the sediments after surface conditions became arid, and would extend the habitability window within the shallow subsurface. Key Points: There were three phases of fracture formation during burial. All resulted from hydraulic fracturingPore pressure was greater than the combined rock tensile strength and horizontal confining pressure, so (largely) vertical fractures formedWater escaped through this fracture network from depth toward the surface. This could extend habitability in the shallow subsurface [ABSTRACT FROM AUTHOR]
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Abstract:Fractures in sedimentary rocks preserved within Gale crater record the deformational and burial history of the sediment infill. Fracture geometries and morphology can be used to time other geologic events, such as: compaction, diagenesis, fluid migration, geochemistry, and broader tectonic stresses within a basin. The rover Curiosity acquired images to construct 3D digital outcrop models used for characterization of fracture sets exposed in aeolian strata of the Mirador formation at Maria Gordon notch, identifying four distinct fracture sets. Three fracture sets formed during burial, and one during exhumation. The first group (Sets 1 and 2) consisted of bedding‐parallel and bedding‐bounded vertical fractures associated with early lithification and hydraulic fracturing of the rock as water escaped from isolated pores. Fracture Set 3—Vertical sulfate‐filled fractures—formed after a second episode of diagenesis, as water escaped from deeper within the sedimentary succession. The final fracture set is barren and associated with exhumation of the crater fill. Modeling burial stress suggests that Sets 1 and 2 would form at depths greater than 1 km. The tensile strength of the rocks is generally higher than anticipated due to the absence of shear fractures (faults). Fracture Sets 1–3 demonstrate dewatering of the strata during burial, which continued up until maximum burial at ∼4.7 km. This water was driven toward the surface, providing water for diagenesis and alteration reactions and could have reasonably extended the habitability window within Gale crater. Plain Language Summary: Gale crater contains a mound of sediment that accumulated under a mixture of wet, and then increasingly dry conditions. As lake sediments were buried and lithified, water became trapped in the pore spaces. With increasing burial depth, the pore water pressure increased until it exceeded the tensile strength of the rock, causing fractures to form. Because the confining weight of the overlying rocks was normally greater than the horizontal confining forces, these fractures typically formed in a sub‐vertical orientation. The timing of different fracture sets corresponds to different stages of burial, and the interactions between fractures can be used to time events within the subsurface, such as compaction and lithification of the sediments, the ground water geochemistry, and external tectonic compression on the basin. Fracturing occurred in four stages: three sets formed during burial, associated with dewatering of the accumulated sediment, and the fourth set was associated with the exhumation of Mount Sharp. The dewatering process would drive water upwards into shallower strata, driving diagenesis, and lithification of the sediments after surface conditions became arid, and would extend the habitability window within the shallow subsurface. Key Points: There were three phases of fracture formation during burial. All resulted from hydraulic fracturingPore pressure was greater than the combined rock tensile strength and horizontal confining pressure, so (largely) vertical fractures formedWater escaped through this fracture network from depth toward the surface. This could extend habitability in the shallow subsurface [ABSTRACT FROM AUTHOR]
ISSN:21699097
DOI:10.1029/2024JE008843