Petrology of a supra-subduction zone ophiolite (Elaz1g, Turkey)

Abstract

The Elaz1g region in eastern Taurus, Turkey, exposes Paleozoic-Tertiary metamorphic, magmatic, and sedimentary units. Contacts between the different units are mostly tectonic, but there are also primary sedimentary, and intrusive contacts. The metamorphic rocks of the Elaz1g region are the Bitlis-Pütürge and Keban-Malatya massifs, which are a single tectonostratigraphic unit that has been tectonically disrupted and fragmented during the Upper Cretaceous. Magmatic rocks in the region are represented by ophiolitic units, magmatic arc products, and young volcanic rocks. The sedimentary units are represented by Upper Cretaceous - Tertiary marine and lacustrine sedimentary rocks. In the study area, the metamorphic units are represented by the Paleozoic Pütürge metamorphic rocks composed of phyllite, slate, mica schist, quartz-muscovite schist, calc-schist, and low-grade metamorphite. The ophiolite that is described in this paper is composed of wehrlite-pyroxenite, gabbro, diabase dykes, and dykes cutting gabbro. These units are cut by the granitic rocks of the Upper Cretaceous Elaz1g magmatic suite. The lithological and geochemical data on the rocks of Kömürhan ophiolite indicate that these rocks were derived from crystallization of an enriched mid-ocean ridge basalt (MORB)-type magma. The Kömürhan ophiolite formed in a supra-subduction spreading zone during the Cretaceous; related to this event is the north-dipping subduction of the southern branch of Neo-Tethys ocean, which began spreading in the Late Triassic. The crust was thickened by the development of an island arc and by the thrusting of the Pütürge metamorphic rocks onto this island arc in response to north-south compression during the Late Cretaceous. The magma formed by partial melting of the subducted slab giving rise to granitic rocks that cut the upper parts of the ophiolite. The ophiolite and the Elaz1g magmatic suite attained their present position after the Middle Eocene.

Upper Cretaceous-Tertiary Geology/Stratigraphy of Pertek and Its Vicinity (Tunceli̇, Turkey)

“…The first subduction has started in the ocean and supra subduction zone ophiolites have developed with the subduction (İspendere, Kömürhan and Guleman). While Kömürhan ophiolites developed as oceanic crust on the supra subduction zone (Turan et al, 1995;Beyarslan and Bingöl, 1996;Bingöl and Beyarslan, 1996;Beyarslan and Bingöl, 2000), the gabbro, diabase, basalt and andesitic volcanics developed in the upper part (Herece et al, 1992). The basalts, which consists of the upper part of the Kömürhan ophiolites, are late Senonian according to pelagic fauna described in samples (Santonian-early Maastrichtian) and early Maastrichtian in andesitic volcanics (Herece et al, 1992).…”

“…It is stated that the depositional environment of Elazığ magmatics are products of arc-backarc (Hempton, 1985), arc-forearc (Yazgan and Chessex, 1991) of the ensimatic island arc, and the ensimatic island arc products of the supra subduction zone ophiolites due to intraoceanic subduction-obduction (Beyarslan and Bingöl 2000;Robertson, 2002). Supra-subduction zone ophiolites and ensimatic island arc volcanics are unconformably overlain by late Maastrichtian-Selandian Harami formation.…”

“…On the other hand; the ophiolitic deposit, which is located below and in the western extension of Elazığ magmatics in the vicinity of Hazar Lake, was named as Kömürhan ophiolites (Yazgan, 1983;Poyraz, 1988). Kömürhan ophiolites consist of three tectonic slices (Yazgan 1983;Poyraz 1988;Yazgan and Chessex 1991;Beyarslan and Bingöl 1996;Beyarslan and Bingöl, 2000) and its upper tectonic slice is the basement unit of the Baskil arc unit (Yazgan an Chessex, 1991). The lower tectonic slice was dated as; 127±14my, 89.5±5my by K/Ar method.…”

Keban ve Karakaya Barajları arası Fırat Nehri'nin kıyı sedimentleri ve su jeokimyası özellikleri

“…[25]. Aynı zamanda, Elazığ Magmatitlerinin, Kömürhan Ofiyoliti üzerinde dalma-batmanın geç evrede geliştiği düşünülmektedir [26,27]. Yukarıda belirtilen tüm birimleri, Keban Barajından, Karakaya Barajına kadar Fırat Nehri akım yönü boyunca görmek mümkündür.…”

Travertine occurrences along major strike-slip fault zones: structural, depositional and geochemical constraints from the Eastern Anatolian Fault System (EAFS), Turkey

“…On the otherhand, ophiolitic masses are emplaced on the continental crust (Beyarslan & Bingöl, 2000;Parlak, Höck, Kozlu, & Delaloye, 2004;Parlak & Robertson, 2004;Robertson, 2002Robertson, , 2004Yalınız, Floyd, & Göncüoğlu, 1996. Tertiary units deposited in back-arc basins are most common (Aksoy, Türkmen, & Turan, 2005;Aktaş & Robertson, 1984;Cronin et al, 2000;Özkul & Kerey, 1996;Yazgan, 1984).…”