Evidence of Eocene high-temperature/high-pressure metamorphism of ophiolitic rocks and granitoid intrusion related to Neotethyan subduction processes (Doğanşehir area, SE Anatolia)

Abstract

New data for regionally important granulite facies metaophiolitic rocks and crosscutting granitoids rocks are presented and discussed. The high-temperature/high-pressure Berit metaophiolite is cut by unmetamorphosed Eocene (51-45 Ma) granitoid rocks. The highest metamorphic grade occurs in blocks of mafic granulites. Enveloping amphibolite facies rocks reflect retrograde metamorphism related to exhumation. Sm-Nd (pyroxene-garnet-amphibole -whole rock) isochron ages of 52-50 Ma for the granulite facies rocks are interpreted to represent the time of cooling of the granulite facies rocks. The over-riding Malatya metamorphic unit to the north is also intruded by Eocene granitoid rocks. The granulite facies metamorphism of the metaophiolitic rocks is inferred to have formed in the roots of an Eocene magmatic arc, with accentuated heat flow being provided by subduction of a spreading ridge, or rupture of the subducting slab. The high-temperature/high-pressure metamorphism was followed by exhumation, as indicated by field structural relations and the evidence of retrograde metamorphism. The Eocene arc magmatism can best be explained by northward subduction of the Southern Neotethys, which persisted after the time of latest Cretaceous regional ophiolite emplacement until the collision of the Eurasian (Anatolian) and Arabian continents during the Early-Mid Miocene. Subsequent Plio-Quaternary leftlateral strike-slip strongly affected the area.Supplementary material: Four supplementary tables giving the whole rock geochemistry of the granitoids, mineral geochemistry of the granulite facies rocks, LA-MC-ICP-MS zircon U -Pb data belonging to granitoids and Sm-Nd data belonging to granulite facies rocks and two documents giving the detailed analytical procedures and detailed petrography of the granitoids are available at www.geolsoc.org.uk/SUP18588

Late Cretaceous–Miocene sedimentary development of the Arabian continental margin in SE Turkey (Adıyaman region): Implications for regional palaeogeography and the closure history of Southern Neotethys

“…Widespread extension and magmatism affected the over-riding Tauride plate during the Early Eocene, associated with the regional formation of the Maden basin, with the implication that the Southern Neotethys was still subducting northwards during this time (e.g. Yılmaz, l993;Robertson et al, 2006Karao lan et al, 2013Karao lan et al, lan et al, 2013 (Braud, 1987;Agard et al, 2005;Jassim and Goff, 2006;Vincent et al, 2007;Allen and Armstrong, 2008;Ballato et al, 2011;Mouthereau et al, 2012). However, none of the evidence from the over-riding plate can be unambiguously related to collision with Arabia.…”

Petrogenesis of kyanite‐ and corundum‐bearing mafic granulite in a meta‐ophiolite, SE Turkey

“…Parlak, Rızaoğlu, Bağci, Karaoğlan, & Höck, ; Yılmaz, Yiğitbaş, & Genç, ; Figure ). The SE Anatolian ophiolites have been correlated with other Late Cretaceous ophiolites in the Bitlis‐Zagros suture zone; these now‐scattered ophiolites are thought to represent a single ophiolite sheet emplaced between the Late Cretaceous and middle Eocene (Genç, Yiğitbaş, & Yılmaz, ; Karaoğlan, Parlak, Klötzli, Koller, & Rızaoğlu, ; Karaoğlan, Parlak, Robertson, et al., ; Parlak et al., ; Robertson et al., , ). Most are slightly (greenschist facies or lower) to unmetamorphosed.…”

“…Metagabbroic rocks within the Berit meta‐ophiolite show evidence for high‐pressure–high‐temperature (HP–HT) metamorphism; that is, granulite, and possibly eclogite, facies metamorphism (Karaoğlan, Parlak, Robertson, et al., ). There is considerable evidence for disequilibrium textures such as symplectite and corona structures, providing an opportunity to reconstruct reaction history and interpret P–T paths and tectonic history.…”

“…There is considerable evidence for disequilibrium textures such as symplectite and corona structures, providing an opportunity to reconstruct reaction history and interpret P–T paths and tectonic history. A post‐peak near‐isothermal decompression path has been proposed to explain symplectite textures in Berit mafic granulite (Karaoğlan, Parlak, Robertson, et al., ), although the sequence of crystallization in reaction textures is more consistent with isobaric cooling (this study). This paper presents new results of an investigation of the P–T– deformation evolution of high‐grade metagabbro in the Berit meta‐ophiolite (Doğanşehir region; Figures and ).…”

“…Geological map of the Doğanşehir region (modified from Karaoğlan, Parlak, Robertson, et al. ) draped onto a Digital Elevation Model, with selected sample locations and representative structural data. Box indicates the location of Figure …”