Tez özetleri Astronomi ve Uzay Bilimleri Anabilim Dalı

Petrogenesis of The Eastern Part of Gölova Massif

Gölova Massif is a metamorphic rock association, comprising dominantly basic magmatic rocks and is located at the S margin of E Pontides, to the N of the İzmir-Ankara-Erzincan Suture Zone. Gölova Massif is commonly considered to be the equivalents of Nilüfer Unit of the Karakaya Complex of W Anatolia, regarding their stratigraphic similarities. Gölova Massif is made up of basic volcanogenic rocks and interbedded limestones and cherts at the base. Thic bedded limestones form the upper most part of the Massif. This sequence is cut by a trondjhemitic intrusion and by a number of dacitic dykes and sills and were then subject to metamorphism and deformation. The metamorphics was invaded by dacitic sills and dykes and, a quartz-diorite pluton. The Massif is in tectonic contact with the Palaeocene ophiolite derived clastics (Taşdemir Formation) to the north and east.

The oldest unit that unconformably overlies both the Gölova Massif and the Taşdemir Formation is the Mendemebaşı formation of Mid to Upper Eocene age, suggesting that the Massif was exhumed and came to a contact with the Taşdemir Formation by the Mid-Eocene. Pliocene lake deposits (KıranTepe formation) covers a large area in the region. This unit unconformably overlies all the units decribed above.

Gölova Massif was folded along a WNW-ESE axis, accomponied by formation of mesoscopic structures such as foliation and stretching lineations. Final exhumation of the Massif took place after the formation of the North Anatolian Fault Zone and as a result a number of strike-slip faults dissected the study area. Travertines occur locally along the fault zones of the study area. The rivers cut deep into their valleys in response to rapid uplift and deposited alluviums and alluvial fan deposits. Alluvial terraces are locally preserved on the valley slopes.

Islan arc- and within plate-type basaltic rocks of the Gölova Massif are tholeiitic to alkaline in composition. The cross-cutting metatrondjhemite is of calc-alkaline in composition and suggests arc-type setting of formation. The arc-type nature of the metabasites is completely different and rules out any correlation with the Nilüfer Unit of W Anatolia.

Presence of two contrasting volcanic unit in the Massif without any detectable unconformity in between and intrusion of calc-alkaline magmatics suggest that the stratigraphy of Gölova Massif was formed in an environment of litospheric stretching. In such extensional settings, first volcanic products are commonly of arc-type, derived from partial melting of lithospheric mantle. The arc-type volcanics are replaced with within plate-type volcanics with the gradual influence of astenospheric melts with progressive extension. This extension is thought to related to rifting of an Upper Cretaceous arc located at the S margin of Pontides, as documented recently in the studies of Central and Eastern Pontides.

YAVAŞ Ferhat

Danışman : Prof. Dr. Süleyman DALGIÇ

Anabilim Dalı : Jeoloji Mühendisliği

Mezuniyet Yılı : 2008

Tez Savunma Jürisi : Prof. Dr. Süleyman DALGIÇ

Prof. Dr. Atiye TUĞRUL

Doç. Dr. Ali Malik GÖZÜBOL

Doç. Dr. Hayrettin KORAL

Yard. Doç. Dr. Özkan CORUK