Long-runout landslides and the long-lasting effects of early water activity on Mars: COMMENT

Shaller, Philip J.

doi:10.1130/g37491c.1

Cited by 6 publications

(5 citation statements)

References 4 publications

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“…These landslide aprons have unexpectedly long runout distances and cover unexpectedly large surfaces (Quantin et al, 2004a(Quantin et al, , 2004bLucas and Mangeney, 2007). They also display longitudinal ridges and furrows, which is a classical morphological signature of landslide emplacement on glaciers (Lucchitta, 1978;Shaller and Komatsu, 1994;De Blasio, 2011). These characteristics are consistent with the assumption that a relict glacial fill is currently buried below the stack of landslide aprons.…”

Section: Flow Patternsupporting

confidence: 67%

“…The dynamics of these landslides remain controversial, mostly because their debris aprons have singular morphologies, unexpectedly long runout distances, and cover unexpectedly wide areas, comprised in the range between those of dry subaerial landslides and those of wet submarine landslides (Lucchitta, 1979;Quantin et al, 2004aQuantin et al, , 2004bLucas and Mangeney, 2007). Interestingly, some studies noted the morphological similarities of Martian landslides and landslides occurring on terrestrial glaciers (Lucchitta, 1978(Lucchitta, , 1979Shaller and Komatsu, 1994;De Blasio, 2011). In particular, they had pointed out that landslide aprons in Valles Marineris have striking morphological similarities with landslide aprons on terrestrial glaciers such as the Sherman and Black Rapids glaciers in Alaska (Shugar and Clague, 2011).…”

Section: Paraglacial and Supraglacial Collapse Of Valley Wallsmentioning

confidence: 99%

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One million cubic kilometers of fossil ice in Valles Marineris: Relicts of a 3.5Gy old glacial landsystem along the Martian equator

et al. 2014

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Self-consistent landform assemblages suggest that Valles Marineris, the giant valley system that stretches along the Martian equator, was entirely glaciated during Late Noachian to Early Hesperian times and still contains huge volumes of fossil ice. Some of these glacial landform assemblages are illustrated here, with representative examples selected in three regions: Ius Chasma, Central Candor Chasma and the junction between Coprates Chasma and Capri Chasma. A morphological boundary separating an upper spur-and-gully morphology from a smooth basal escarpment has been spectacularly preserved along valley walls throughout Valles Marineris. The boundary winds around topographic obstacles and displays long-wavelength variations in elevation. It is associated with lateral benches, hanging valleys and truncated spurs. Comparisons with terrestrial analogs indicate that it is most reasonably interpreted as a glacial trimline. Chasma floors are covered by various kinds of terrains, including hummocky terrains, platy terrains, lateral banks, layered benches and a draping mantle. Landforms in these terrains and their spatial relationship with the interpreted trimline suggest that they correspond to various disintegration stages of an ancient glacial fill, currently protected by a superficial cover of ablation till. Altogether, these landforms and terrains compose a full glacial landsystem with wet-based glaciers that were able to flow and slide over their beds. It was most probably fed by ice accumulating at low elevations directly from the atmosphere onto valley floors and walls, with only minor contributions from tributary glaciers flowing down from higher elevations. Similar fossil glacial landsystems dating back from the early Martian history are to be expected in many other low-latitude troughs such as chasmata, chaos, valleys, impact craters and other basins.

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Section: Flow Patternsupporting

confidence: 67%

Section: Paraglacial and Supraglacial Collapse Of Valley Wallsmentioning

confidence: 99%

One million cubic kilometers of fossil ice in Valles Marineris: Relicts of a 3.5Gy old glacial landsystem along the Martian equator

et al. 2014

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“…Beyond the lack of support for clays in the remote sensing data, our field reconnaissance of the landslide uncovered no visual evidence for clay deposits in the area, and our XRD data (Table 7) demonstrate an almost complete lack of clays in the landslide debris itself. Furthermore, clays do not form reliable lubricants except when saturated and sheared slowly [78]. Based on these observations and considerations, we conclude that clay lubrication is not a viable mechanism for emplacement of the EVL.…”

Section: Alternative Emplacement Mechanismsmentioning

confidence: 80%

The Eureka Valley Landslide: Evidence of a Dual Failure Mechanism for a Long-Runout Landslide

Shaller¹,

Doroudian²,

Hart³

2020

Lithosphere

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Long-runout landslides are well-known and notorious geologic hazards in many mountainous parts of the world. Commonly encompassing enormous volumes of debris, these rapid mass movements place populations at risk through both direct impacts and indirect hazards, such as downstream flooding. Despite their evident risks, the mechanics of these large-scale landslides remain both enigmatic and controversial. In this work, we illuminate the inner workings of one exceptionally well-exposed and well-preserved long-runout landslide of late Pleistocene age located in Eureka Valley, east-central California, Death Valley National Park. The landslide originated in the detachment of more than 5 million m3 of Cambrian bedrock from a rugged northwest-facing outcrop in the northern Last Chance Range. Its relatively compact scale, well-preserved morphology, varied lithologic composition, and strategic dissection by erosional processes render it an exceptional laboratory for the study of the long-runout phenomenon in a dry environment. The landslide in Eureka Valley resembles, in miniature, morphologically similar “Blackhawk-like” landslides on Earth, Mars, and minor planet Ceres, including the well-known but much larger Blackhawk landslide of southern California. Like these other landslides, the landslide in Eureka Valley consists of a lobate, distally raised main lobe bounded by raised lateral levees. Like other terrestrial examples, it is principally composed of pervasively fractured, clast-supported breccia. Based on the geologic characteristics of the landslide and its inferred kinematics, a two-part emplacement mechanism is advanced: (1) a clast-breakage mechanism (cataclasis) active in the bedrock canyon areas and (2) sliding on a substrate of saturated sediments encountered and liquefied by the main lobe of the landslide as it exited the main source canyon. Mechanisms previously hypothesized to explain the high-speed runout and morphology of the landslide and its Blackhawk-like analogs are demonstrably inconsistent with the geology, geomorphology, and mineralogy of the subject deposit and its depositional environment.

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“…The MGSC structures follow this trend (Figure 2) with an effective friction coefficient <<0.1. Based on field observations, laboratory testing, and numerical modeling, numerous mechanisms have been proposed to reduce 3 of 25 sliding friction of long-runout landslides below typical values for rocks and explain long runout (e.g., Shaller & Smith-Shaller, 1996). These include bulk fluidization mechanisms based in the physics of granular flow, such as acoustic fluidization (Johnson et al, 2016;Melosh, 1979) and fragmentation and spreading (Davies & McSaveney, 2009), gas fluidization of basal gravels in the presence of carbon dioxide (Aharonov & Anders, 2006;Anders et al, 2010), and mechanisms that lubricate the slip surface to reduce the frictional resistance to sliding.…”

mentioning

confidence: 99%

Structural Relationships Across the Sevier Gravity Slide of Southwest Utah and Implications for Catastrophic Translation and Emplacement Processes of Long Runout Landslides

Braunagel

Griffith

Biek

et al. 2023

Geochem Geophys Geosyst

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The physical processes that facilitate long‐distance translation of large‐volume gravity slides remain poorly understood. To better understand these processes and the controls on runout distance, we conducted an outcrop and microstructural characterization of the Sevier gravity slide across the former land surface and summarize findings of four key sites. The Sevier gravity slide is the oldest of three mega‐scale (>1,000 km2) collapse events of the Marysvale volcanic field (Utah, USA). Field observations of intense deformation, clastic dikes, pseudotachylyte, and consistency of kinematic indicators support the interpretation of rapid emplacement during a single event. Furthermore, clastic dikes and characteristics of the slip zone suggest emplacement involved mobilization and pressurized injection of basal material. Across the runout distance, we observe evidence for progressive slip delocalization along the slide base. This manifests as centimeter‐ to decimeter‐thick cataclastic basal zones and abundant clastic dikes in the north and tens of meters thick basal zones characterized by widespread deformation of both slide blocks and underlying rock near the southern distal end of the gravity slide. Superimposed on this transition are variations in basal zone characteristics and slide geometry arising from interactions between slide blocks during dynamic wear and deposition processes and pre‐existing topography of the former land surface. These observations are synthesized into a conceptual model in which the presence of highly pressurized fluids reduced the frictional resistance to sliding during the emplacement of the Sevier gravity slide, and basal zone evolution controlled the effectiveness of dynamic weakening mechanisms across the former land surface.

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Long-runout landslides and the long-lasting effects of early water activity on Mars: COMMENT

Cited by 6 publications

References 4 publications

One million cubic kilometers of fossil ice in Valles Marineris: Relicts of a 3.5Gy old glacial landsystem along the Martian equator

One million cubic kilometers of fossil ice in Valles Marineris: Relicts of a 3.5Gy old glacial landsystem along the Martian equator

The Eureka Valley Landslide: Evidence of a Dual Failure Mechanism for a Long-Runout Landslide

Structural Relationships Across the Sevier Gravity Slide of Southwest Utah and Implications for Catastrophic Translation and Emplacement Processes of Long Runout Landslides

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