Earth-prints repository, logo   DSpace

About DSpace Software
|earth-prints home page | roma library | bologna library | catania library | milano library | napoli library | palermo library
Please use this identifier to cite or link to this item:

Authors: Bestmann, M.*
Pennacchioni, G.*
Frank, G.*
Göken, M.*
de Wall, H.*
Title: Pseudotachylyte in muscovite-bearing quartzite: Coseismic friction-induced melting and plastic deformation of quartz
Title of journal: Journal of structural geology
Series/Report no.: 2/33/(2011)
Publisher: Elsevier Science Limited
Issue Date: 2011
DOI: 10.1016/j.jsg.2010.10.009
Keywords: Quartz
Abstract: Thin (0.5e2 mm thick) pseudotachylyte veins occur within muscovite-bearing (w10% volume), amphibolite-facies quartzites of the Schneeberg Normal Fault Zone (Austroalpine, Southern Tyrol, Italy). Pseudotachylytes are associated with precursor localized plastic microshear zones (50e150 mm thick) developed sub-parallel to the host-rock foliation and with conjugate sets oriented at a high angle to the foliation. Such microshear zones are characterized by recrystallization to ultrafine-grained (1e2 mm grain size) mosaic aggregates of quartz showing a transition from a host-controlled to a random crystallo- graphic preferred orientation towards the shear zone interior. Subsequent coseismic slip mainly exploited these microshear zones. Microstructural analysis provides evidence of extensive friction- induced melting of the muscovite-bearing quartzite, producing a bimodal melt composition. First, the host-rock muscovite was completely melted and subsequently crystallized, mainly as K-feldspar. Then, about 60% volume of the ultrafine-grained quartz underwent melting and crystallized as spherulitic rims (mostly consisting of quartz ` Ti ` Fe) around melt-corroded quartz clasts. The two melts show immiscibility structures in the major injection veins exploiting microshear zones at high angles to the quartzite foliation. In contrast, they were mechanically mixed during flow along the main fault veins.
Appears in Collections:04.06.99. General or miscellaneous
Papers Published / Papers in press

Files in This Item:

File SizeFormatVisibility
science-57.55 MBAdobe PDFonly authorized users View/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Share this record




Stumble it!



Valid XHTML 1.0! ICT Support, development & maintenance are provided by CINECA. Powered on DSpace Software. CINECA