Sedimentological investigations of eocene deposits in the Northwest of Suluova (Amasya) area

Ill ABSTRACT (Master Thesis) SEDIMENTOLOGICAL INVESTIGATIONS OF EOCENE DEPOSITS IN THE NORTHWEST OF SULUOVA (AMASYA) AREA Calibe Koç Fırat University Graduate School of Natural and Applied Sciences Department of Geological Engineering 2002, Page: 52 The studied area is located in the northwest of Suluova township of Amasya. Gological units are represented by Doğdu Formation (Santonian-Campanian), Çeltek Formation (Lower Eocene), Armutlu Formation (Lower-Middle Eocene), Osmanoğlu Formation (Upper Eocene) and Neogene deposits. In the studied area, Doğdu Formation consists of thin-middle bedded white-grey limestone, which commonly contain crack. This formation is overlain unconformably by Lower Eocene Çeltek Formation which composed of an alternation coal and organic rich mudstone, passes laterally and vertically into mudstone, sandstone and conglomerates. Çeltek Formation is characterized by delta plain and delta front fades, which is important the reason why it has coal. Delta plain deposits consist of organic rich grey mudstone and coal while delta front deposits have composed of grey-green mudstones. siltstones, thick-bedded sandstones and lenticular body conglomerates. There are benthic and planctic foraminiferia in the grey-green mudstones. At this study, Lower-Middle Eocene Armutlu Formation has been divided as Tersakan stream member and Kayadüzü volcanic member. Tersakan stream member consists of marinal delta front, shoreface, offshore-transition and offshore fades associations. DeltaIV front facies consist of thick-bedded sandstones, red sandstones containing bentic and planctic foraminiferia, grey-green mudstones ve coal. Shoreface facies is characterized by large-scale cross-bedded sandstones. These sandstones include commonly bioturbation and rarely benthic foraminiferia. Offshore-transition facies association composed of an alternation of parallel laminated sandstones, waved-bedded sandstones, grey-green mudstones and red mudstone facies. Offshore facies associations consist of grey-green mudstones which includes fine grained sandstone levels. This facies association passes laterally-vertically into offshore- transition facies association. Middle Eocene Kayadüzü member which has lithology of volcanizm spreading within marine environment consists of an alternations of bedded mudstones, volcanic sandstone, tuff, aglomerata and volcanic rock such as basalt, andesite. dacite, diabas. Red-grey volcanic rock show columner and flow structures. Osmanoğlü Formation is represented by carbonate-tuff and clastic rocks. Age of it has been offered as Upper Eocene according to stratigraphic position. Eocene deposits are overlain unconformably by, Neogene deposits which consist of clay-calcite cemented conglomerates and sandstones. In the studied area, there are various faults, anticlinals and senclinals which parallel, oblique and vertical to North Anatolian Fault. These structures generally strike NW-SE and NE-SW. The formation of the faults are related with shear stress in the region. Local topographic reliefs were formed by the tectonic structures on the Doğdu Formation. In the south of basin, delta plain-delta front facies of Çeltek Formation deposited at a bay which associated with the tectonic structures. Toward the north of the basin the delta front deposits passes laterally and vertically into prodelta, offshore and offshore-transition facies association of the Armutlu Formation. The limestone of Doğdu Formation was onlapped by marinal deposits of the Armutlu Formation associated with transgression. KEY WORDS: Sedimentology, delta, shoreface, offshore, coal, Çeltek Formation, Armutlu Formation, Amasya.