 | | Journal (article/letter/editorial) | | 12997 Quartz–coesite–stishovite relations in shocked metaquartzites from the Vredefort impact structure...structure, South Africa John G. SPRAY * and Suporn BOONSUE Planetary and Space Science Centre, University...revision accepted 12 September 2017) Abstract–Coesite and stishovite are developed in shock veins within...radius of ~30 km from the center of the 2.02 Ga Vredefort impact structure. This work focuses on deploying...loading of >5 < 35 GPa. Within the shock veins, coesite forms anhedral grains, ranging in size from 0.5 |  | | Book | | sites, such as the Bushveld Igneous Complex in South Africa, remains acontroversy to this day. Although...at Mid-Century 9. The Craters of the Moon 10. Coesite and Shatter Cones 11. Meteorite Craters in Canada...Metamorphism 14. The Bushveld Igneous Complex and the Vredefort Ring 164 15. Sudbury: A Geologic Puzzle 16....Meteor Crater 14 15 18 20 21 22 23 26 33 4.1 The South Swamp, probable location of the ae 4.2 Tunguska...Aerial photograph of Richat dome, in northwest Africa 93 8.3 8.4 Aerial photograph of New Quebec crater |  | | Journal (article/letter/editorial) | | the coesite and stishovite associated with the pseudotachylite of the Vredefort Dome, South Africa J,E...Geological Surt~ey, Private bag Xl12, Pretoria, South Africa Received January 29, 1990; revision accepted...accepted November 6, 1990 ABSTRACT The Vredefort Dome represents the uplift centre of a well known 2.00 Ga...distribution and post-shock metamorphic alteration of coesite and stishovite which were poorly documented up...phase". Stishovite crystallized first, followed by coesite. The high-pressure conditions may have lasted an |  | | Journal (article/letter/editorial) | | the coesite and stishovite associated with the pseudotachylite of the Vredefort Dome, South Africa" by...Johannesburg, South Africa a Department of Geology, University of the Orange Free State, P.O.Box 339,... Bloemfontein 9300, South Africa Department of Geology, University of the Witwatersrand, P.O. Bits 205Q...205Q Johannesburg, South Africa Received September 17, 1991, revision accepted June 16, 1992 1. Introduction...without reservation an impact origin for the Vredefort structure . Their misgivings are mainly based |  | | Journal (article/letter/editorial) | | Shock-induced growth and metastability of stishovite and coesite in lithic clasts from suevite of the Ries impact... Abstract The microtextures of stishovite and coesite in shocked non-porous lithic clasts from suevite...They formed from silica melt as well as by solid-state transformation. In weakly shocked rocks (stage I)...phase and PDFs to diaplectic glass in the solid state. Coesite formed during unloading occurs in two textural...textural varieties. Granular micrometre-sized coesite occurs embedded in silica melt glass along former fractures |  | | Journal (article/letter/editorial) | | metamorphic history of the Vredefort dome at approximately 2 Ga as revealed by coesite-stishovitebearing pseudotachylites...Survey, Private Bag X112, Pretoria, South Africa ABSTRACT The Vredefort dome (2.0Ga) represents the central...been focused on the degree of alteration of the coesite-stishovite-bearing pseudotachylite veins that formed...caused by continental crustal extension in a stress-free environment and the lack of deformation is probably...Key words: coesite; post-shock metamorphism; pseudotachylite; static metamorphism; Vredefort impact structure |  | | Journal (article/letter/editorial) | | of the Vredefort Dome for the thermal and structural evolution of the Witwatersrand Basin, South Africa...University of the Witwatersrand, Johannesburg, South Africa With 5 Figures Received July 14, 1998; revised...version accepted January 26, 1999 Summary The Vredefort Dome represents an area of significant ( ~ 10...Basin. Impact-related deformation features in the Vredefort rocks facilitate the separation of metamorphic...impact event. Zusammenfassung Die Bedeutung des Vredefort-Domes fiir die thermische und strukturelle Entwicklung |  | | Journal (article/letter/editorial) | | argon-40/argon-39 dating of coesite- and stishovite-bearing pseudotachylytes and the age of the Vredefort impact event...University ofthe Witwatersrand, Johannesburg, South Africa (Received 1994 May 27; accepted in revisedform...pseudotachylytic rocks from the controversial Vredefort structure of South Africa using the laser microprobe 40ArP9Ar...40ArP9Ar dating technique. Coesite- and stishovitebearing veins in a quartzite from the Central Rand Group...rock (French and Nielsen, 1990). The dating of coesite- and stishovite-bearing veins equates the shock |  | | Journal (article/letter/editorial) | | Pre-Existing Basement Granulites in the Vredefort Structure, South Africa, and Their Relations to Pseudotachylite...metamorphism which is related in time to the Vredefort event. On the basis of experimental data for the...compositions near 3 tool % A1203. In the absence of free silica hercynitic spinel appears as an additional...static metamorphism, which was probably caused by a local, deep-seated magma diapir. On this basis, the meteorite...meteorite impact hypothesis for the origin of the Vredefort Structure is considered less likely than a mechanism |  | Jaret, Steven J., Phillips, Brian L., King, David T., Glotch, Tim D., Rahman, Zia, Wright, Shawn P. (2017) An unusual occurrence of coesite at the Lonar crater, India. Meteoritics & Planetary Science, 52 (1) 147-163 doi:10.1111/maps.12745 | Journal (article/letter/editorial) | | doi: 10.1111/maps.12745 An unusual occurrence of coesite at the Lonar crater, India Steven J. JARET1*, Brian...revision accepted 06 September 2016) Abstract–Coesite has been identified within ejected blocks of shocked...India. This is the first report of coesite from the Lonar crater. Coesite occurs within SiO2 glass as distinct...distinct ~30 lm spherical aggregates of “granular coesite” identifiable both with optical petrography and...and with micro-Raman spectroscopy. The coesite+glass occurs only within former silica amygdules, which |  | | Journal (article/letter/editorial) | | stress in quartz from the impact site of Vredefort, South Africa KAI CHEN1, MARTIN KUNZ2, NOBUMICHI TAMURA2...stishovite-bearing quartzite from the Vredefort meteorite impact site in South Africa reveals features that are attributed...Average lattice strains of 1400 microstrains in Vredefort quartz are much higher compared to values (500)...compressive and tensile residual stresses, in Vredefort quartz, shear stresses associated with lamellar...lamellar boundaries dominate. Key-words: Vredefort impact site, quartz, Dauphiné twinning, residual stress |  | Rajesh, H.M., Knoper, M.W., Belyanin, G.A., Safonov, O.G., Schmidt, C. (2020) Petalite postdating spodumene in pegmatite as a consequence of the ~2.02 Ga meteorite impact in the Vredefort structure, southern Africa. Lithos, 376. 105760pp. doi:10.1016/j.lithos.2020.105760 | Journal (article/letter/editorial) | | ~2.02 Ga meteorite impact in the Vredefort structure, southern Africa H.M. Rajesh, M.W. Knoper, G.A....~2.02 Ga meteorite impact in the Vredefort structure, southern Africa, LITHOS (2020), https://doi.org/10...~2.02 Ga meteorite impact in the Vredefort structure, southern Africa H.M. Rajesh1*, M.W. Knoper2, G...Department of Geology, University of Johannesburg, South Africa 3 Korzhinskii Institute of Experimental Mineralogy...Petrology and Volcanology, Geological Faculty, Moscow State University, Russia 5 GFZ German Research Centre |  | | Journal (article/letter/editorial) | | the coesite and stishovite associated with the pseudotachylite of the Vredefort Dome, South Africa" J...Geological Survey of South Africa, Private Bag X112, Pretoria 0001, South Africa Received April 6, 1992...that the polygonal and asymmetrical shape of the Vredefort Dome is not characteristic of an impact structure...such a control to explain the pear shape of the Vredefort structure . 2. Section 2, last sentence of first...Section 2, middle of second paragraph Reimold et al . state that the overturning of the collar and the concentric |  | | Journal (article/letter/editorial) | | temperature metamorphism in thevredefort Dome, South Africa: anticlockwise pressure-temperature path followed...Witwatersrand,PlBag 3, WITS 2050,Johannesburg, South Africa AND 7: WALLMACH Department of Geology, University...Pretoria 0002, South Africa Pelitic metasediments of the Witwatersrand Supergroup in the Vredefort Dome contain...facies metamorphism with the formation of the Vredefort Dome. Instead, it indicates that the doming event...pseudotachylite; Vredefort Dome 1. INTRODUCTION The Vredefort Dome, situated 120 km SSW of Johannesburg, South Africa |  | | Journal (article/letter/editorial) | | "PSEUDOTACHYLITE IN THE SOUTH BOUNDARY EAULT ATTHE COOKE SHAET, WITWATERSRAND BASIN, SOUTH AERICA BY PW. MAMBANE...MAMBANE ET AL., SOUTH AERICAN JOURNAL OE GEOLOGY 114.2, 109-120 w.u. REIMOLD Museum für Naturkunde - Leibniz...reimold@mfn-berlin.de © 2012 June Geological Society of South AMca Mambane et al. (2011) presented a geological...occurrence of different fault rock types at the South Boundary Fault on Cooke Shaft, in the West Rand...referred as PTB) being present at that location. They state that based on the conclusion of previous research |  | | Journal (article/letter/editorial) | | shock-induced pseudotachylites, Vredefort impact structure, South Africa Elizaveta Kovaleva, Matthew S...shock-induced pseudotachylites, Vredefort impact structure, South Africa, LITHOS (2020), https://doi.org/10...shock-induced pseudotachylites, Vredefort impact structure, South Africa Elizaveta Kovalevaa,* kovalevae@ufs...University of the Free State, 205 Nelson Mandela Drive, 9300 Bloemfontein, South Africa b ur na lP ...Geology, University of Pretoria, 0028 Pretoria, South Africa Journal Pre-proof ABSTRACT Impact-generated |  | | Journal (article/letter/editorial) | | felsic and mafic rocks from the Vredefort impact structure, South Africa. Implications for the experimental...University of the Free State, 205 Nelson Mandela Drive, 9300 Bloemfontein, South Africa e-mail: kovalevae@ufs...University of the Free State, 205 Nelson Mandela Drive, 9300 Bloemfontein, South Africa e-mail: fouriefd@ufs...ac.at © 2018 December Geological Society of South Africa Abstract While the formation of tectonic PTs...considered in detail, even though impact PTs in the Vredefort structure are found in various lithologies. Here |  | | Journal (article/letter/editorial) | | in synthesizing the high-pressure polymorphs, coesite and stishovite, compared to natural occurrences...metamorphosed quartz and its other phases (namely, coesite, stishovite, diaplectic glass and lechatelierite).... . . . . . . . . . . . . . . . . . . . . . . Coesite and Stishovite ..................................percentage, -18%, have documented occurrences of the coesite and/or stishovite highpressure polymorphs. This... (4) partial transformation to stishovite and coesite and ( 5 ) melting and quenching to lechatelierite |  | | Journal (article/letter/editorial) | | INVITED REVIEW The melt rocks of the Vredefort impact structure – Vredefort Granophyre and pseudotachylitic...Private Bag 3, P.O. Wits 2050, Johannesburg, South Africa Received 22 February 2005; accepted 26 July...regional mining activity make the Vredefort impact structure in South Africa an exceptional laboratory for...impactgenerated melt rock occur in the Vredefort Structure: the Vredefort Granophyre – impact melt rock – and...frictional melting. On the other hand, rocks in the Vredefort Dome – the central uplift of the impact structure |  | | Journal (article/letter/editorial) | | Letters 144 ( 1996) 369-387 A 2.023 Ga age for the Vredefort impact event and a first report of shock metamorphosed...Johannesburg, South Africa ’ Department qf Geology. University of the Orange Free State, P.O. Box 339...339, Bloemfontein 9300. South Africa Received 10 June 1996: revised 3 September 1996: accepted 13 September...Granophyre from the controversial Vredefort Structure, South Africa, provide new and compelling evidence...pseudotachylitic breccia from the central part of the Vredefort Structure provides a good approximation of the |  | | Report (chapter) | | (SIC). A similar relationship exists within the Vredefort impact structure, with the additional association...association of the high-pressure SiO2 polymorphs coesite and stishovite. These S- (shock-dominant) type pseudotachylytes...dyke-like bodies seen in the Vredefort Dome of South Africa. Vredefort is now accepted as one of Earth's...Pseudotachylyte dykes commonly reach 5 m thickness at Vredefort. The largest known pseudotachylyte occurs in the...pseudotachylyte body (referred to locally as the Frood, or South Range, Breccia Belt) is c. 45 km long and up to |  | | Journal (article/letter/editorial) | | Elements of Quartz in Basement Rocks of the Vredefort Dome, South Africa W. Schreyer and O. Medenbach Institut...with the Vredefort event itself. Introduction: P r o b l e m a t i c O r i g i n of the Vredefort D o m...m e The Vredefort Dome in South Africa is one of the most conspicuous circular structures within the...controlled impacts of large meteorites. For the Vredefort Dome the results of recent investigations have...Bushveld intrusion towards the Trompsburg body in the south. The detailed petrographic study by Bisschoff (1969) |  | | Report (chapter) | | some of the Witwatersrand gold deposits at the Vredefort impact structure. Impact-related hydrothermal...associated with the Sudbury impact structure. Although Vredefort and Sudbury contain world-class mineral deposits...during which the target rocks readjust to the 'local' structural and lithological anomaly that constitutes...(StOffler et al. 1994; Spray & Thompson 1995), and Vredefort (Therriault et al. 1997). Although some of their...metastable polymorphs, such as stishovite and coesite from quartz (Chao et al. 1962; Langenhorst 2002) |  | Reimold, W.U., Hoffmann, M., Hauser, N., Schmitt, R-T., Zaag, P.T., Mohr-Westerheide, T. (2016) A geochemical contribution to the discussion about the genesis of impact-related pseudotachylitic breccias: Studies of PTB in the Otavi and Kudu Quarries of the Vredefort Dome support the“In Situ Formation”hypothesis. South African Journal of Geology, 119 (3) 453-472 doi:10.2113/gssajg.119.3.453 | Journal (article/letter/editorial) | | of PTB in the Otavi and Kudu Quarries of the Vredefort Dome support the “In Situ Formation” hypothesis...n.de © 2016 September Geological Society of South Africa Abstract This work is aimed at contributing...of the outer crystalline core of the Vredefort Dome (South Africa) have been investigated petrographically...populations only support derivation of PTB from local precursor material (granitic gneiss and amphibolite...chemical systematics of melt rock and possible local precursors are fully consistent with this petrographic |  | | Journal (article/letter/editorial) | | Printed in USA. Meleorilics Original size of the Vredefort Structure: Implications for the geological evolution... P. 0. Wits 2050, Johannesburg, Republic of South Africa. *Correspondence author's e-mail address: atherriault@gsc...deeply eroded Vredefort impact structure within the Witwatersrand Basin, South Africa. Here, we estimate...an original multi-ring form. At this size, the Vredefort impact structure encompasses the bulk of the Witwatersrand...owe its preservation to the Vredefort impact. In addition, the Vredefort impact event may have been the |
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