Batı Anadolu Çubukludağ Neojen havzası Neojen Stratigrafisi Neojen volkanizması
The Lower-Middle Miocene fill of Çubukludağ basin, formed as an asimetric depression under the control of strike-slip Tuzla Fault, comprises Çatalca, Bahçecik, Yeniköy and Tahtalı formations, all of which are studied under the name Çubukludağ group, as well as Cumaovası volcanics. Composed of lacustrine and fluvial deposits with coal-bearing marsh interbeds, Çatalca formation has not any observed lower stratigraphic contact. Bahçecik formation, which overlies the Çatalca formation with an unconformity marked by an abrupt change in the depositional environment, consists of red-claret red conglomerates deposited in a lacustrine fan delta, including freshwater alga-bearing lacustrine limestone interbeds (Sarımustafa Member). Yeniköy formation overlies the Bahçecik formation unconformably and contains fan deltaic and lacustrine deposits. The lower part of a fan delta succession, named as Akselvi member, is made from red-claret red fluvial conglomerates with a low-textural maturity. The upper part is a succession that is dominated by fluvial sandstone, pebbly sandstone, conglomerate with interbeds of lacustrine claystone-siltstone. Lacustrine Edil member, overlying Akselvi member with a relationship of lateralvertical transition, contains a laminated-shale dominated succession and bears felsic pyroclastic interbeds, products representing an earlier period for Cumaovası volcanism.
Became active in late periods of the sedimentation during which Yeniköy formation occurred, Cumaovası volcanism has two stages of volcanism marked by calc-alkaline rhyolitic volcanics, showing a lateral interfingering relationship with the deposition of Tahtalı formation. K-Ar ages ranging from 13,0±0,4 Ma to 13,8 Ma were obtained from rhyolite lavas emplaced on first-stage pyroclastics. The initial stage of phreatomagmatic volcanism originated in the lake where Edil member was deposited. The lake was entirely filled in the main explosion stage marked with pyroclastic flow deposits and rhyolite lavas. With the emplacement of first-stage Cumaovası volcanics, the basin in which Yeniköy formation had been deposited was closed and the sub basin was formed in the area where Tahtalı formation was filled, located in east of the volcanic axis. Composed of mainly braided river deposits, Tahtalı formation has a lateral interfingering relationship with second-stage Cumaovası volcanics. Intermittent lacustrine deposits, described as Çamköy limestone member, rest on/within Tahtalı formation initiated with alluvial fan deposits (Sakartepe member) overlying over Bornova Flysch Zone at the southern margin of the basin unconformably.
Gaziemir group, which is built from lower alluvial Akçaköy formation and upper lacustrine Buca formation, indicates the sedimentation occurred during Late Miocene-Early Pliocene. Akçaköy formation reflects sedimentation of the Late Miocene basin, took place on an alluvial fan from its western and eastern basin margins toward its center. Lacustrine Buca formation comprises limestone-dolomitic limestone and green claystone-siltstone successions (Develi member), overlying Akçaköy alluvial succession laterally passing at the basin margins and vertically along the interior parts.
Neogene Çubukludağ basin Neogene Stratigraphy Neogene volcanism West Anatolia
Birincil Dil | Türkçe |
---|---|
Konular | Yer Bilimleri ve Jeoloji Mühendisliği (Diğer) |
Bölüm | Makaleler - Articles |
Yazarlar | |
Yayımlanma Tarihi | 1 Ocak 2019 |
Gönderilme Tarihi | 7 Ocak 2019 |
Kabul Tarihi | 31 Ocak 2019 |
Yayımlandığı Sayı | Yıl 2019 Cilt: 62 Sayı: 1 |
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