Geological Study South Eastern Region of Lake Van

Abstract

The principal mountains of the region studied, are Artos (3475 m), Pelli (3060 m), Singer (2900 m), Arnas (3550 m) and Kuvveşehap (3500 m). The stratigraphy of the southeastern region of Lake Van is somewhat complicated.The stratigraphic column consist of the following: Paleozoic (Upper Permian), Upper Cretaceous (Maestrichtian), Upper Cretaceous-Paleocene, Eocene, Neogene, and Quaternary. Quartzites, Limestones, Crystalline Limestones and Schists make up the Upper Permian in the area. Schwagerina, Parafusulina, Polydiexodina were identified in the limestone member. The Conglomerates, foliated limestones, Globigerina limestones and radiolarites form the Upper Cretaceous. In the last two fossiliferous units, Globigerina cf. cretacea, Globotruncana linnei d'Orb. Globotruncana cf. stuarti J. de. Lapp. Cyclolites krumbecki Stef., Trochosmilia bilobata Mich.; Hippurites loftusi Wood, Exogyra columba Lamk., Loftusia elongata, Lagena diffringens J. de Lapp. were identified. A mixed facies of limestones, marls and sandstones, overlay the Upper Cretaceous. Due to fossil content this facies is placed in the Upper Cretaeeous and Paleocene; Miliolidae, Nummulites sp. Miseellanea miscella cf. d'Arch, Lithophyllum, Globigerina cf. cretacea, Globotruncana cf. stuarti J. de Lapp. were identified in the limestone units. In the region, Miscellanea miscella d'Arch, Alveolina cf. primaeva Reichel, Nummulites subatacicus containing limestones represent the Eocene. With the aid of fossil evidence the rocks belonging to the Neogene were divided into Lower Miocene, Middle Miocene and generally Neogene. Lower Miocene is made up of conglomerates, sandstones and limestones. The middle Miocene is represented by the alternating beds of sandstones and marls. In this region the Neogene is fossil bearing, Chlamys scabriusculus Font. (variety), Chlamys cf. rotundata Lamk., Miogypsina sp., Miolepidocyclina burdigalensis, Amphistegina, Lithothamnium are amongst the many identified. Quaternary is represented by the alluvium and the terrace deposits which are co n s olidated by travertine (=caliche). The main eruptive rocks of the region are andesite, gabbro, diabase, lamprophyre, pyroxenite and serpentine. The eruptive bodies are in the form of cones, sills and dikes. There is evidence of volcanic activity during the Paleozoic. During the Cretaceous and Paleocene there was more intense eruptive activity. Presence of the thrusting and imbricate structures indicate the intensity of the orogenic movements. Many tectonic brecciaes and mylonites are found in the area. In some places individual (affect of erosion) Paleozoic masses lay over the Cretaeeous like a Klippe. Alpine orogenic movements slowed down towards the end of Tertiary, but never stopped. Hercynian structures are partly obscured by the alpine orogeny. The tectonic forces acted from both south and north to a general direction of N75 — 80W foldings. The tectonic high transversal of Van which was named by Ed. Parejas is not a single one. Results of thus study indicate that it has two branches. One of them crosses Pilidağ. The other one runs along the eastern border of the region. No deposits of economic importance were noted, however, some traces of copper ond hematite were seen. There is also some baryte in Paleozoic area.

Özet

Tetkik edilen bölgenin başlıca dağları; Artos (3475 m.), Pelli (3060 m.), Arnas (3550 m.), Singer (2900 m.), Vaviran (3000 m.) ve Kuvveşehap (3500 m.) dağlarıdır. Bölgenin stratigrafisi biraz karışıktır. Stratigrafik vaziyet şu şekildedir: Paleozoik (Üst Permien), Üst Kretase (Mastrihtien), Üst KretasePaleosen, Eosen, Neojen ve Kuaterner'dir. Kuarsitler, Kalkerler, Kristalen Kalker ve şistler Üst Permien'i teşkil ederler. Kalkerler içinde (Schwagerina, Parafusulina, Polydiexodina) lar bulduk. Üst Kretase; Konglomera'lardan, levhalı kalkerlerden, Globigerina'lı kalkerlerden ve Radiolaritler'den müteşekkildir. Bu kalker ve grelerde de (Globigerina cf. cretacea, Globotruncana linnei d'Orb., Globotruncana cf. stuarti J. de Lapp., Cyclolites krumbecki Stef., Trochosmilia bilobata Mich., Hippurites loftusi Wood, Exogyra columba Lamk., Loftusia elongata, Lagena diffringens J. de Lapp.) fosillerini bulduk. Kesif kalkerlerden, marn gre ve bazi Eruptif sahrelerden müteşekkil (Karışık fasies) adını verdiğimiz bir fasies mevcuttur. İhtiva ettiği fosillere göre yaşı Üst Kretase-Paleosen'dir. Başlıca fosilleride: (Miliolidae, Nummulites sp., Miscellanea cf. miscella d'Arch., Lithophyllum, Globigerina cf. cretacea, Globotruncana cf. stuarti de Lapp.) olup kalkerler içinde bulunurlar. Bölgedeki Eosen Kalkerlerinde de (Miscellanea miscella d'Arch., Alveolina cf. primaeva Reich., Nummulites subatacicus) fosilleri bulunur. Fosillerinin delaletiyle Neojen'e ait arazi; Alt Miosen, Orta Miosen, Umumiyetle Neojen diye ayrılabildi. A. Miosen; konglomeralardan, gre ve kalkerlerden ibarettir. O. Miosen münavebeli gre ve marn tabakalarından müteşekkildir. Bölgede Neojen'in ihtiva ettiği mühim fosiller: (Chlamys scabriusculus Font. (variete), Ghlamys cf. rotundata Lamk., Miogypsina sp., Miolepidocyclina burdigalensis, Amphistegina, Lithothamnium) lardır. Kuaterner; alluvion, çimentolanmış teras çakılları ve travertenlerden ibarettir.