Electron microscopy study of hyalomylonites—evidence for frictional melting in landslides

Masch, L.; Wenk, Hans‐Rudolf; Preuss, Ekkehard

doi:10.1016/0040-1951(85)90103-9

Cited by 107 publications

(56 citation statements)

References 14 publications

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“…Granular flow mechanisms account for frictional interactions between the fragments in the slide that result in frictional heating of the clasts in the basal layer. Such a process is apparent in the Langtang, Köfels (Masch et al 1985), and Arequipa volcanic landslides (Legros et al 2000), as evidenced by the presence of a hyalomylonite (frictional melt) layer at the base of each slide. Legros et al (2000) further suggest that frictional melting occurs during the last stage of the slide as it changes from nondepositional to depositional stages.…”

Section: Geologic Setting Of Low Shock High Strain Rate Deformationmentioning

confidence: 99%

Impact‐induced frictional melting in ordinary chondrites: A mechanism for deformation, darkening, and vein formation

Bogert

Schultz

Spray

2003

Meteorit & Planetary Scien

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Abstract-High speed friction experiments have been performed on the ordinary chondrites El Hammami (H5, S2) and Sahara 97001 (L6, S3) using an axial friction-welding apparatus. Each sample was subjected to a strain rate of 10 3 to 10 4 s -1 , which generated 250 to 500 mm-deep darkened zones on each sample cube. Thin section analyses reveal that the darkened areas are composed of silicate glass and mineral fragments intermingled with dispersed submicron-size FeNi and FeS blebs.Fracturing of mineral grains and the formation of tiny metallic veins define the extent of deformation beyond the darkened shear zone. These features are not present in the original meteorites. The shear zones and tiny veins are quite similar to certain vein systems seen in naturally deformed ordinary chondrites. The experiments show that shock deformation is not required for the formation of melt veins and darkening in ordinary chondrites. Therefore, the presence of melt veins and darkening does not imply that an ordinary chondrite has undergone severe shock deformation. In fact, high strain rate deformation and frictional melting are especially important for the formation of veins at low shock pressures.

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Section: Geologic Setting Of Low Shock High Strain Rate Deformationmentioning

confidence: 99%

Impact‐induced frictional melting in ordinary chondrites: A mechanism for deformation, darkening, and vein formation

Bogert

Schultz

Spray

2003

Meteorit & Planetary Scien

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“…1), a pseudotachylite zone has been found which is interpreted to have been formed by friction melting along the slip surface of a mega landslide in gneisses called TsergoRi landslide (Masch et al 1985;Weidinger et al 2002). Fission-track age of zircon taken from fault gouge around the pseudotachylite is estimated to be 51 ± 13 ka (Takagi et al 2007).…”

Section: A Possible Cause Of Draining Of the Paleo-kathmandu Lake At mentioning

confidence: 99%

Two times lowering of lake water at around 48 and 38 ka, caused by possible earthquakes, recorded in the Paleo-Kathmandu lake, central Nepal Himalaya

Sakai

Fujii

Sugimoto

et al. 2016

Earth Planets Space

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Sedimentary facies and micro-fossil analyses, and AMS 14 C dating were performed in order to reveal the water-level fall events and draining process of the lake (Paleo-Kathmandu Lake) that existed in the past in the Central Nepal Himalaya. The sedimentary facies change from the lacustrine Kalimati Formation to the deltaic Sunakothi Formation in the southern and central Kathmandu basin, and the abrupt and prominent increase of phytoliths Bambusoideae and Pediastrum, and contemporaneous decrease of sponge spicule and charcoal grains around 48 and 38 ka support the lowering of water level at these times. According to the pollen analysis, both events occurred under rather warm and wet climate, thus supporting that they were triggered by tectonic cause and not by climate change. The first event might be linked to a possible occurrence of a large earthquake with an epicenter in the vicinity of the PaleoKathmandu Lake. The occurrence of a mega landslide in Langtang area close to the north of the Kathmandu Valley producing pseudotachylite dated at 51 ± 13 ka could be linked to this earthquake. Finally, the water was completely drained out from the remnant lake at the central part of the Kathmandu basin by ca.12 ka.

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“…5) mit dermaßen großer Geschwindigkeit (ca. 250 km/h), dass es aufgrund der hohen Reibungswärme (z. T. über 1000 Grad C) nahe und entlang der (den) Gleitfläche(n) zu Gesteinsbrekzierung und Gesteinsaufschmelzung kam (Erismann, Heuberger & Preuss, 1977;Masch & Preuss, 1977;Masch, Wenk & Preuss, 1985;Preuss, 1986). Die daraus nach der Abkühlung entstandenen speziellen Metamorphite mit Deformations gefügen wurden in ihrer lokalen Ausbildung früher mit Hyalomylonite (Scott & Drever, 1953), heute als Friktionite bezeichnet.…”

Section: Bewegungsablauf Und Bildungsbedingungen Für Friktionit (Hyalunclassified

The Integration of the Direct and Indirect Methods in Lichenometry for Dating Buddhist Sacred Walls in Langtang Valley, Nepal Himalaya

Emerman

Adhikari²,

Panday³

et al. 2016

Arctic, Antarctic, and Alpine Research

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ZusammenfassungDie gewonnen geologischen, geomorphologischen und geotechnischen Grundlagenerkenntnisse an der im Kristallin weltweit gewaltigsten und einzigartigen Großmassenbewegung des Tsergo Ri im Langthangtal des zentralen Nepal Himalaya entschlüsselten nicht nur den chronologischen Ablauf der Paläo-Ereignisse vor Ort, sondern können auch direkt auf eine Einstufung des rezenten Gefahrenpotentials dieser Gegend und ähnlich geotektonisch-lithologisch positionierter Bereiche des Himalaya und der Erde angewendet werden. Dies konnte vorerst am Beispiel weiterer, kleinerer Bergstürze im Langthangtal selbst, im Kristallin des Annapurna Massivs und mit einem Vergleich zu einer Felslawine in Zentralchina bestätigt werden.

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Electron microscopy study of hyalomylonites—evidence for frictional melting in landslides

Cited by 107 publications

References 14 publications

Impact‐induced frictional melting in ordinary chondrites: A mechanism for deformation, darkening, and vein formation

Impact‐induced frictional melting in ordinary chondrites: A mechanism for deformation, darkening, and vein formation

Two times lowering of lake water at around 48 and 38 ka, caused by possible earthquakes, recorded in the Paleo-Kathmandu lake, central Nepal Himalaya

The Integration of the Direct and Indirect Methods in Lichenometry for Dating Buddhist Sacred Walls in Langtang Valley, Nepal Himalaya

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