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Titre	Origin of large-volume pseudotachylite in terrestrial impact structures
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Auteur	Riller, U; Lieger, D; Gibson, R L; Grieve, R A F; Stöffler, D
Source	Geology vol. 38, no. 7, 2010 p. 619-622, https://doi.org/10.1130/G30806.1
Image
Année	2010
Séries alt.	Secteur des sciences de la Terre, Contribution externe 20100103
Éditeur	Geological Society of America
Document	publication en série
Lang.	anglais
DOI	https://doi.org/10.1130/G30806.1
Media	papier; en ligne; numérique
Formats	pdf
Province	Ontario
SNRC	41I/15
Région	Sudbury; Vredefort
Lat/Long OENS	-81.0000 -80.5000 47.0000 46.7500
Lat/Long OENS	27.7500 27.7500 -27.0000 -27.5000
Sujets	cratères; cratères météoriques; pseudotachylites; Bassin de Sudbury ; Structure d'impact de Vredefort ; géologie extraterrestre; minéralogie
Illustrations	cartes de localisation; graphiques
Diffusé	2010 07 01
Résumé	(disponible en anglais seulement) Large-volume pseudotachylite bodies in impact structures are dike like and consist of angular and rounded wall-rock fragments enveloped by a microcrystalline and sporadically glassy matrix that crystallized from a melt. Knowledge of the formation of pseudotachylite bodies is important for understanding mechanics of complex crater formation. Most current hypotheses of pseudotachylite formation inherently assume that fragmentation and melt generation occur during a single process. Based on the structure of pseudotachylite bodies at Sudbury (Canada) and Vredefort (South Africa), we show that these processes differ in time and space. We demonstrate that the centimeter- to kilometer-scale bodies are effectively fragment- and melt-filled tension fractures that formed by differential rotation of target rock during cratering. Highly variable pseudotachylite characteristics can be accounted for by a single process, i.e., drainage of initially superheated impact melt into tension fractures of the crater floor.
GEOSCAN ID	285968