Pseudotachylyte

Last updated
Purple and green pseudotachylyte veins in outcrop (Sierra Nevada Mountains, California) Pseudotachylyte ladder veins.jpg
Purple and green pseudotachylyte veins in outcrop (Sierra Nevada Mountains, California)

Pseudotachylyte (sometimes written as pseudotachylite) is an extremely fine-grained to glassy, dark, cohesive rock occurring as veins [1] that form through frictional melting and subsequent quenching during earthquakes, [2] large-scale landslides, and impacts events. [3] Chemical composition of pseudotachylyte generally reflects the local bulk chemistry, though may skew to slightly more mafic compositions due to the preferential incorporation of hydrous and ferro-magnesian minerals (mica and amphibole, respectively) into the melt phase. [4]

Contents

Pseudotachylyte was first documented by Shand in the Vredefort Impact Structure and was named due to its close resemblance to tachylyte, a basaltic glass. [5] Though pseudotachylyte is reported to have a glassy appearance, they are extremely susceptible to alteration and are thus rarely found to be entirely composed of glass. [6] [7] Typically, they are completely devitrified into a very fine-grained material with quench textures such as chilled margins, [8] [9] radial and concentric clusters of microcrystalites (spherulites) [10] [11] or as radial overgrowths of microcrystalites on clasts, [12] as well as skeletal and spinifex microcrystalites. [6] [10]

Radial overgrowth of plagioclase microcrystallite laths on plagioclase survivor grain in pseudotachylyte (Asbestos Mountain Fault, California) Radiating microcrystallites on survivor grain in pseudotachylyte.tif
Radial overgrowth of plagioclase microcrystallite laths on plagioclase survivor grain in pseudotachylyte (Asbestos Mountain Fault, California)

Formation

Seismic faulting

Seismic pseudotachylyte fault vein with several injection veins within mylonite (Fort Foster, Maine). Pseudotachylyte fault vein with several injection veins.jpg
Seismic pseudotachylyte fault vein with several injection veins within mylonite (Fort Foster, Maine).

Pseudotachylytes have been referred to as "fossil earthquakes" as they represent definitive evidence of seismic slip. [2] During seismic faulting (earthquakes), pseudotachylyte forms through an extreme concentration of frictional sliding onto a thin surface of a fault. The friction creates heat, and because rocks are insulators, the temperature increases on this surface allowing the rock to melt. [13] This generates a "fault vein" which are often accompanied by "injection veins" [2] that open from the fault vein as opening mode cracks. [14] A melt origin for pseudotachylyte was controversial for some time, [15] with some researchers favouring extreme comminution for their generation (crush-origin). [16] Ample evidence of direct crystallisation from a melt [1] [17] though, has more or less put this argument to rest with most researchers defining pseudotachylyte as having a melt origin.

Laboratory experiments investigating how pseudotachylytes form have shown that the initial phase of formation involves the flash melting of asperities that eventually grow and join together into larger patches of a high viscosity melt. [18] The high viscosity of these melt patches raises the fault's coefficient of friction, hindering sliding. [19] As the patches of melt continue to grow and join together, they form a continuous melt layer with a lower viscosity, which reduces the fault's coefficient of friction, [18] effectively lubricating the fault and allowing sliding to occur more easily. [19] Once the melt layer has reached some critical thickness, frictional heat can no longer be generated, and the melt begins to quench and crystallise thus again increasing the melt's viscosity and begins acting as a viscous brake to sliding. [20] Once sliding is stopped, the quenching of the melt layer welds the fault shut and restores its strength to that of the unfaulted surrounding rock. [20] [21]

Abundance of seismic pseudotachylyte in nature

There is an apparent lack of pseudotachylyte in the geologic record relative to the observed seismicity of today, [6] [7] which brings into question if this is an issue of the rarity of its production, lack of recognition in the field, or its ability to be preserved. [9] It was once thought that pseudotachylyte could only be produced in dry, crystalline rock, [2] this however, has been shown to be incorrect. [8] Therefore, its production is likely not as rare as originally thought. Pseudotachylyte is often closely associated with other extremely fine grained rocks (e.g. mylonite and cataclasite), [1] and is extremely prone to alteration that often renders it unrecognisable [6] [7] which supports arguments that pseudotachylyte production isn't rare, but rather is likely to go unrecognised, and thus unreported.

Landslides

Pseudotachylytes have been observed at the base of some large-scale landslide deposits. [3] The formation of pseudotachylyte along the base of a landslide occurs due to the same processes as earthquake-generated pseudotachylyte - frictional heating during gliding along the base of the detachment melts the surrounding rock. [3] [22] They are similar in appearance to earthquake-generated pseudotachylyte. Some notable examples of landslide-generated pseudotachylyte in the geologic record is the Arequipa volcanic landslide deposit in Peru from approximately 2.4 million years ago, [23] and the Langtang landslide deposit in Nepal which occurred between 30,000 - 25,000 years ago. [22] Pseudotachylyte has also been found along the base of more modern landslides, such as the landslide generated by the 1999 Taiwan earthquake. [24]

Impact structures

Pseudotachylyte breccia from Vredefort impact structure, South Africa Pseudotachylite Breccia of Vredefort in South Africa.jpg
Pseudotachylyte breccia from Vredefort impact structure, South Africa

Pseudotachylyte has also been associated with impact structures. [25] [26] Pseudotachylyte in impact craters typically occurs as abundant irregular, anastomosing, and dike-like bodies that contain several large and small rounded inclusions of the impacted, or target, rock in a dense fine-grained to glassy black to greenish matrix. [26] Individual pseudotachylyte bodies within impact craters are not uniform over long distances, and may change in size and shape drastically within meters or tens of meters. [26] The most extensive examples of impact related pseudotachylytes come from impact structures that have been deeply eroded below the floor of the crater, such as in case of the Vredefort impact structure in South Africa, and the Sudbury impact structure in Canada. [5] [27] [25]

Impact-generated pseudotachylytes are classified into two types depending on their method of formation. [26] [25] [28] S-Type pseudotachylytes, also known as "shock veins", [27] [25] are found as small (<1 cm, typically <1 mm) [26] [25] glassy veins that contain high-pressure mineral polymorphs like coesite and stishovite. [26] [25] [28] These shock veins are thought to form via frictional and shock melting due to the higher pressure compressive stages (%need to make it skip to formation section%) of the shockwave expansion. [25] E-Type (endogenic) pseudotachylytes are formed via frictional melting of the target rock due to high-speed slip caused by the collapse of the crater margin. [27] [25]

Pseudotachylyte vs. impact melt in impact structures

Though pseudotachylyte and impact melt within impact structures are visually similar, both occurring as dike-like bodies, they are chemically different. [25] [26] Since pseudotachylyte is derived locally, it will reflect the composition of the wall-rock from which it formed. [25] Impact melts are generated from a much larger volume of rock by instantaneous shock melting, so their chemical compositions will be more reflective of regional-scale mixing and homogenization during melting, particularly in heterogeneous terranes. [25] In the Sudbury impact structure, researchers have been able to distinguish dikes of pseudotachylyte from dikes of impact melt based on their chemical compositions. [25] [29]

See also

Related Research Articles

<span class="mw-page-title-main">Asthenosphere</span> Highly viscous, mechanically weak, and ductile region of Earths mantle

The asthenosphere is the mechanically weak and ductile region of the upper mantle of Earth. It lies below the lithosphere, at a depth between ~80 and 200 km below the surface, and extends as deep as 700 km (430 mi). However, the lower boundary of the asthenosphere is not well defined.

<span class="mw-page-title-main">Fault (geology)</span> Fracture or discontinuity in displaced rock

In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep.

<span class="mw-page-title-main">Manicouagan Reservoir</span> Lake in Quebec, Canada

Manicouagan Reservoir is an annular lake in central Quebec, Canada, covering an area of 1,942 km2 (750 sq mi). The lake island in its centre is known as René-Levasseur Island, and its highest point is Mount Babel. The structure was created 214 (±1) million years ago, in the Late Triassic, by the impact of a meteorite 5 km (3 mi) in diameter. The lake and island are clearly seen from space and are sometimes called the "eye of Quebec". The lake has a volume of 137.9 km3 (33.1 cu mi).

<span class="mw-page-title-main">Rochechouart impact structure</span> Asteroid impact structure in France

Rochechouart impact structure or Rochechouart astrobleme is an impact structure in France. Erosion has over the millions of years mostly destroyed its impact crater, the initial surface expression of the asteroid impact leaving highly deformed bedrock and fragments of the crater's floor as evidence of it.

<span class="mw-page-title-main">Vredefort impact structure</span> Largest verified impact structure on Earth, about 2 billion years old

The Vredefort impact structure is the largest verified impact structure on Earth. The crater, which has since been eroded away, has been estimated at 170–300 kilometres (110–190 mi) across when it was formed. The remaining structure, comprising the deformed underlying bedrock, is located in present-day Free State province of South Africa. It is named after the town of Vredefort, which is near its centre. The structure's central uplift is known as the Vredefort Dome. The impact structure was formed during the Paleoproterozoic Era, 2.023 billion years ago. It is the second-oldest known impact structure on Earth, after Yarrabubba.

Fault friction describes the relation of friction to fault mechanics. Rock failure and associated earthquakes are very much a fractal operation. The process remains scale-invariant down to the smallest crystal. Thus, the behaviour of massive earthquakes is dependent on the properties of single molecular irregularities or asperities.

<span class="mw-page-title-main">Mylonite</span> Metamorphic rock

Mylonite is a fine-grained, compact metamorphic rock produced by dynamic recrystallization of the constituent minerals resulting in a reduction of the grain size of the rock. Mylonites can have many different mineralogical compositions; it is a classification based on the textural appearance of the rock.

<span class="mw-page-title-main">Mendocino Triple Junction</span> Point where the Gorda plate, the North American plate, and the Pacific plate meet

The Mendocino Triple Junction (MTJ) is the point where the Gorda plate, the North American plate, and the Pacific plate meet, in the Pacific Ocean near Cape Mendocino in northern California. This triple junction is the location of a change in the broad plate motions which dominate the west coast of North America, linking convergence of the northern Cascadia subduction zone and translation of the southern San Andreas Fault system. This region can be characterized by transform fault movement, the San Andreas also by transform strike slip movement, and the Cascadia subduction zone by a convergent plate boundary subduction movement. The Gorda plate is subducting, towards N50ºE, under the North American plate at 2.5 – 3 cm/yr, and is simultaneously converging obliquely against the Pacific plate at a rate of 5 cm/yr in the direction N115ºE. The accommodation of this plate configuration results in a transform boundary along the Mendocino Fracture Zone, and a divergent boundary at the Gorda Ridge. This area is tectonically active historically and today. The Cascadia subduction zone is known to be capable of producing megathrust earthquakes on the order of MW 9.0.

In geology, igneous differentiation, or magmatic differentiation, is an umbrella term for the various processes by which magmas undergo bulk chemical change during the partial melting process, cooling, emplacement, or eruption. The sequence of magmas produced by igneous differentiation is known as a magma series.

<span class="mw-page-title-main">Dome (geology)</span> Geological deformation structure

A dome is a feature in structural geology where a circular part of the Earth's surface has been pushed upward, tilting the pre-existing layers of earth away from the center. In technical terms, it consists of symmetrical anticlines that intersect each other at their respective apices. Intact, domes are distinct, rounded, spherical-to-ellipsoidal-shaped protrusions on the Earth's surface. A slice parallel to Earth's surface of a dome features concentric rings of strata. If the top of a dome has been eroded flat, the resulting structure in plan view appears as a bullseye, with the youngest rock layers at the outside, and each ring growing progressively older moving inwards. These strata would have been horizontal at the time of deposition, then later deformed by the uplift associated with dome formation.

A cataclastic rock is a type of fault rock that has been wholly or partly formed by the progressive fracturing and comminution of existing rocks, a process known as cataclasis. Cataclasis involves the granulation, crushing, or milling of the original rock, then rigid-body rotation and translation of mineral grains or aggregates before lithification. Cataclastic rocks are associated with fault zones and impact event breccias.

The Walker Lane is a geologic trough roughly aligned with the California/Nevada border southward to where Death Valley intersects the Garlock Fault, a major left lateral, or sinistral, strike-slip fault. The north-northwest end of the Walker Lane is between Pyramid Lake in Nevada and California's Lassen Peak where the Honey Lake Fault Zone, the Warm Springs Valley Fault, and the Pyramid Lake Fault Zone meet the transverse tectonic zone forming the southern boundary of the Modoc Plateau and Columbia Plateau provinces. The Walker Lane takes up 15 to 25 percent of the boundary motion between the Pacific Plate and the North American Plate, the other 75 percent being taken up by the San Andreas Fault system to the west. The Walker Lane may represent an incipient major transform fault zone which could replace the San Andreas as the plate boundary in the future.

In geology, the term exhumation refers to the process by which a parcel of rock, approaches Earth's surface.

<span class="mw-page-title-main">Flat slab subduction</span> Subduction characterized by a low subduction angle

Flat slab subduction is characterized by a low subduction angle beyond the seismogenic layer and a resumption of normal subduction far from the trench. A slab refers to the subducting lower plate. A broader definition of flat slab subduction includes any shallowly dipping lower plate, as in western Mexico. Flat slab subduction is associated with the pinching out of the asthenosphere, an inland migration of arc magmatism, and an eventual cessation of arc magmatism. The coupling of the flat slab to the upper plate is thought to change the style of deformation occurring on the upper plate's surface and form basement-cored uplifts like the Rocky Mountains. The flat slab also may hydrate the lower continental lithosphere and be involved in the formation of economically important ore deposits. During the subduction, a flat slab itself may deform or buckle, causing sedimentary hiatus in marine sediments on the slab. The failure of a flat slab is associated with ignimbritic volcanism and the reverse migration of arc volcanism. Multiple working hypotheses about the cause of flat slabs are subduction of thick, buoyant oceanic crust (15–20 km) and trench rollback accompanying a rapidly overriding upper plate and enhanced trench suction. The west coast of South America has two of the largest flat slab subduction zones. Flat slab subduction is occurring at 10% of subduction zones.

<span class="mw-page-title-main">South China Craton</span> Precambrian continental block located in China

The South China Craton or South China Block is one of the Precambrian continental blocks in China. It is traditionally divided into the Yangtze Block in the NW and the Cathaysia Block in the SE. The Jiangshan–Shaoxing Fault represents the suture boundary between the two sub-blocks. Recent study suggests that the South China Block possibly has one more sub-block which is named the Tolo Terrane. The oldest rocks in the South China Block occur within the Kongling Complex, which yields zircon U–Pb ages of 3.3–2.9 Ga.

<span class="mw-page-title-main">Marie Violay</span> French expert in rock mechanics

Marie Violay is a French expert in rock mechanics. She is an assistant professor and the head of the Laboratory of Experimental Rock Mechanics at EPFL. She teaches rock mechanics, geophysics for engineers and geology.

Mathilde Cannat is a French geologist known for her research on the formation of oceanic crust and the tectonic and magmatic changes of mid-ocean ridges.

Anne M. Tréhu is a professor at Oregon State University known for her research on geodynamic processes, especially along plate boundaries. She is an elected fellow of the American Geophysical Union.

<span class="mw-page-title-main">Volcanic and igneous plumbing systems</span> Magma chambers

Volcanic and igneous plumbing systems (VIPS) consist of interconnected magma channels and chambers through which magma flows and is stored within Earth's crust. Volcanic plumbing systems can be found in all active tectonic settings, such as mid-oceanic ridges, subduction zones, and mantle plumes, when magmas generated in continental lithosphere, oceanic lithosphere, and in the sub-lithospheric mantle are transported. Magma is first generated by partial melting, followed by segregation and extraction from the source rock to separate the melt from the solid. As magma propagates upwards, a self-organised network of magma channels develops, transporting the melt from lower crust to upper regions. Channelled ascent mechanisms include the formation of dykes and ductile fractures that transport the melt in conduits. For bulk transportation, diapirs carry a large volume of melt and ascent through the crust. When magma stops ascending, or when magma supply stops, magma emplacement occurs. Different mechanisms of emplacement result in different structures, including plutons, sills, laccoliths and lopoliths.

James Gregory "Greg" Hirth is an American geophysicist, specializing in tectonophysics. He is known for his experiments in rock deformation and his applications of rheology in development of models for tectonophysics.

References

  1. 1 2 3 Trouw, R.A.J., C.W. Passchier, and D.J. Wiersma (2010) Atlas of Mylonites- and related microstructures. Springer-Verlag, Berlin, Germany. 322 pp. ISBN   978-3-642-03607-1
  2. 1 2 3 4 Sibson, R.H. (1975). "Generation of pseudotachylyte by ancient seismic faulting". Geophysical Journal International. 43 (3): 775–794. Bibcode:1975GeoJ...43..775S. doi: 10.1111/j.1365-246x.1975.tb06195.x .
  3. 1 2 3 Lin, A. (2007). Fossil earthquakes: the formation and preservation of Pseudotachylytes. Lecture Notes in Earth Sciences. Vol. 111. Springer. p. 348. ISBN   978-3-540-74235-7 . Retrieved 2009-11-02.
  4. Magloughlin, J.F.; Spray, J.G. (1992). "Frictional melting processes and products in geological materials: introduction and discussion". Tectonophysics. 204 (3–4): 197–206. Bibcode:1992Tectp.204..197M. doi:10.1016/0040-1951(92)90307-R via Elsevier Science Direct.
  5. 1 2 Shand, S. James (1916-02-01). "The Pseudotachylyte of Parijs (Orange Free State), and its Relation to 'Trap-Shotten Gneiss' and 'Flinty Crush-Rock'". Quarterly Journal of the Geological Society. 72 (1–4): 198–221. doi:10.1144/GSL.JGS.1916.072.01-04.12. ISSN   0370-291X. S2CID   129174160.
  6. 1 2 3 4 Kirkpatrick, James D.; Rowe, Christen D. (2013). "Disappearing ink: How pseudotahcylytes are lost from the rock record". Journal of Structural Geology. 52: 183–198. Bibcode:2013JSG....52..183K. doi: 10.1016/j.jsg.2013.03.003 .
  7. 1 2 3 Fondriest, Michele; Mecklenburgh, Julian; Francois Xavier, Passelegue; Gilberto, Artioli; Nestola, Fabrizio; Spagnuolo, Elena; Rempe, Marieke; Di Toro, Guilio (2020). "Pseudotachylyte alteration and the rapid fade of earthquake scars from the geological record". Geophysical Research Letters. 47 (22). Bibcode:2020GeoRL..4790020F. doi:10.1029/2020GL090020. hdl: 11577/3377649 . S2CID   228918611.
  8. 1 2 Bjornerud, Marcia (2010). "Rethinking conditions necessary for pseudotachylyte formation: Observations from the Otago schists, South Island, New Zealand". Tectonophysics. 490 (1–2): 68–80. Bibcode:2010Tectp.490...69B. doi:10.1016/j.tecto.2010.04.028.
  9. 1 2 Kirkpatrick, J.D.; Shipton, Z.K.; Persano, C. (2009). "Pseudotachylytes: Rarely generated, rarely preserved, or rarely reported?". Bulletin of the Seismological Society of America. 99 (1): 382–388. Bibcode:2009BuSSA..99..382K. doi:10.1785/0120080114.
  10. 1 2 Lin, Aiming (1994). "Glassy pseudotachylyte veins from the Fuyun fault zone, northwest China". Journal of Structural Geology. 16 (1): 71–83. Bibcode:1994JSG....16...71L. doi:10.1016/0191-8141(94)90019-1.
  11. Dunkel, K.G.; Morales, L.F.G.; Jamveit, B. (2021). "Pristine microstructures in pseudotachylytes formed in dry lower crust, Lofoten, Norway". Philosophical Transactions A. 379 (2193). Bibcode:2021RSPTA.37990423D. doi:10.1098/rsta.2019.0423. PMC   7898121 . PMID   33517873.
  12. Prante, Mitchell R.; Evans, James P. (2015). "Pseudotachylyte and fluid alteration at seismogenic depths (Glacier Lakes and Granite Pass Faults), Central Sierra Nevada, USA". Pure and Applied Geophysics. 172 (5): 1203–1227. Bibcode:2015PApGe.172.1203P. doi:10.1007/s00024-014-0989-2. S2CID   129906270 via Springer.
  13. Sibson, R.H. (1986). "Earthquakes and rock deformation in crustal fault zones". Annual Review of Earth and Planetary Sciences. 14: 149–175. Bibcode:1986AREPS..14..149S. doi:10.1146/annurev.ea.14.050186.001053.
  14. Rowe, Christen D.; Kirkpatrick, James D.; Brodsky, Emily E. (2012). "Fault rock injections record paleo-earthquakes". Earth and Planetary Science Letters. 335: 154–166. Bibcode:2012E&PSL.335..154R. doi:10.1016/j.epsl.2012.04.015.
  15. Spray, John G. (1995). "Pseudotachylyte controversy: Fact or friction?". Geology. 23 (12): 1119–1122. Bibcode:1995Geo....23.1119S. doi:10.1130/0091-7613(1995)023<1119:PCFOF>2.3.CO;2 via GeoScience World.
  16. Wenk, H.-R. (1978). "Are pseudotachylites products of fracture or fusion?". Geology. 6 (8): 507–511. Bibcode:1978Geo.....6..507W. doi:10.1130/0091-7613(1978)6<507:APPOFO>2.0.CO;2.
  17. Maddock, R.H. (1983). "Melt origin of fault-generated pseudotachylytes demonstrated by textures". Geology. 11 (2): 105–108. Bibcode:1983Geo....11..105M. doi:10.1130/0091-7613(1983)11<105:MOOFPD>2.0.CO;2.
  18. 1 2 Hirose, T; Shimamoto, T (2005). "Growth of molten zone as a mechanism of slip weakening of simulated faults in gabbro during frictional melting". Journal of Geophysical Research: Solid Earth. 110 (B5). Bibcode:2005JGRB..110.5202H. doi: 10.1029/2004JB003207 .
  19. 1 2 Di Toro, Giulio; Hirose, Takehiro; Nielsen, Stefan; Pennacchioni, Giorgio; Shimamoto, Toshihiko (2006-02-03). "Natural and Experimental Evidence of Melt Lubrication of Faults During Earthquakes". Science. 311 (5761): 647–649. Bibcode:2006Sci...311..647D. doi:10.1126/science.1121012. ISSN   0036-8075. PMID   16456076. S2CID   43080301.
  20. 1 2 Mitchell, Thomas M.; Toy, Virginia; Di Toro, Giulio; Renner, Jörg; Sibson, Richard H. (2016-10-20). "Fault welding by pseudotachylyte formation". Geology. 44 (12): 1059–1062. Bibcode:2016Geo....44.1059M. doi: 10.1130/g38373.1 . ISSN   0091-7613.
  21. Proctor, B; Lockner, D.A. (2016). "Pseudotachylyte increases the post-slip strength of faults". Geology. 44 (12): 1003–1006. Bibcode:2016Geo....44.1003P. doi:10.1130/g38349.1 . Retrieved 2022-11-03.
  22. 1 2 Masch, L.; Wenk, H.R.; Preuss, E. (1985). "Electron Microscopy Study of Hyalomylonites - Evidence for Frictional Melting in Landslides". Tectonophysics. 115 (1–2): 131–160. Bibcode:1985Tectp.115..131M. doi:10.1016/0040-1951(85)90103-9.
  23. Legros, F.; Cantagrel, J.-M.; Devouard, B. (2000). "Pseudotachylyte (Frictionite) at the Base of the Arequipa Volcanic Landslide Deposit (Peru): Implications for Emplacement Mechanisms". The Journal of Geology. 108 (5): 601–611. Bibcode:2000JG....108..601L. doi:10.1086/314421. S2CID   128761395.
  24. Lin, Aiming; Chen, Allen; Liau, Ching-Fei; Lin, Chyi-Chia; Lin, Po-Shen; Wen, Shu-Ching; Ouchi, Toru (2001). "Frictional fusion due to coseismic landsliding during the 1999 Chi Chi (Taiwan) ML 7.3 earthquake". Geophysical Research Letters. 28 (20): 4011–4014. doi: 10.1029/2001GL013253 . S2CID   140161341.
  25. 1 2 3 4 5 6 7 8 9 10 11 12 Spray, John G. (2010). "Frictional Melting Processes in Planetary Materials: from Hypervelocity Impact to Earthquakes". Annual Review of Earth and Planetary Sciences. 38: 359–374. Bibcode:2010AREPS..38..221S. doi:10.1146/annurev.earth.031208.100045.
  26. 1 2 3 4 5 6 7 Chapter 5 of the online book, French, B.M. 1998. Traces of Catastrophe, A handbook of shock-metamorphic effects in terrestrial meteorite impact structures, Lunar and Planetary Institute 120pp.
  27. 1 2 3 Spray, J.G. (1998). "Localized shock- and friction-induced melting in response to hypervelocity impact". In Grady, M.M.; Hutchinson, R.; Rothery, D.A.; McCall, G.J.H. (eds.). Meteorites: Flux with Time and Impact Effects. Special Publications, Geological Society, London. Vol. 140. pp. 195–204. doi:10.1144/GSL.SP.1998.140.01.14. ISBN   9781862390171. S2CID   128704900.
  28. 1 2 Martini, J.E.J. (1991). "The nature, distribution and genesis of the coesite and stishovite associated with the pseudotachylite of the Vredefort Done, South Africa". Earth and Planetary Science Letters. 103 (1–4): 285–300. Bibcode:1991E&PSL.103..285M. doi:10.1016/0012-821X(91)90167-G.
  29. Thompson, Lucy M.; Spray, John G. (1996). "Pseudotachylyte petrogenesis: constraints from the Sudbury impact structure". Contributions to Mineralogy and Petrology. 125 (4): 359–374. Bibcode:1996CoMP..125..359T. doi:10.1007/S004100050228. S2CID   128762378.

    Wieland, F. (2006) Chapter 4: Pseudotachylitic breccias, other breccias and veins. Structural analysis of impact-related deformation in the collar rocks of the Vredefort Dome, South Africa. unpublished PhD. dissertation. School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa.