The sedimentological investigations of şelmo formation in the northern area of Kahta (Adıyaman)

ABSTRACTMaster ThesisTHE SEDIMENTOLOGICAL INVESTIGATIONS OF ŞELMO FORMATIONIN THE NORTHERN AREA OF KAHTA (ADIYAMAN)İlker Yücel ÖĞRENMİŞFırat UniversityGraduate School of Natural and Applied SciencesDepartment of Geological Engineering2006, Page: 55The studied area is located in the north of Kahta township of Adıyaman. Geologicalunits are represented by Pütürge Metamorphics (Palaeozoic-Mesozoic), Koçali Complex(Meastrihtiyen), Besni Formation (Middle-Upper Meastrihtiyen), Hoya Formation ( LowerEocene-Lower Oligocene), Fırat Formation (Burdigaliyen) and Şelmo Formation(Tortoniyen).Pütürge Metamorphics consist of marbles and schists. Koçali Complex composed ofdiorite, serpentinite and radiolarite. Besni Formation consist of reefial limestone. This formationis overlain uncorformably by Hoya Formation which consist of limestone containing benthicforaminifera and dolomites. Hoya formation is overlain by Fırat Formation which consist oflimestones containing abundant algae.Şelmo Formation has been divided as Eski Kahta, Tırpal, Alut and Kahta members.Eski Kahta members at the bottom of the formation is characterized by delta deposits whichconsist of grey mudstone containing marine fossils, large scale cross-bedded sandstone,VIIIhorizontal bedded sandstone-siltstone-mudstone, epsilon cross-bedded sandstone and redmudstone from bottom to top. The Tırpal member, interpreted as braided river deposits and is,composed of graded-bedded conglomerates, thick bedded conglomerates, trough-planar cross- bedded sandstones. Alut member consist of sandy siltstone- siltstone-grey claystonecontaining freshwater ostracodes characterizing lake. Kahta member passes laterally - verticallyinto Alut members. The Kahta member is composed of fining-upward sequence. Stratifiedconglomerates, trough-planar cross-bedded sandstones occurin the lower part of thesequence and, red mudstone are in the upper part. These sequences characterize meanderingriver faciesImportant tectonic structures such as ENE-WSW oriented folds and thrust faults weredeveloped in the study area.The facies characteristics and regional tectonic indicate that the Şelmo Formation wasdeveloped in foreland basin during Tortonian.KEY WORDS: Sedimentology, braided river, meandering river, lake, delta, ŞelmoFormation, foreland basin, Adıyaman.IX