Morphologic and physical features of pillow basalts of the Yüksekova Complex around Elazığ (Eastern Anatolia, Turkey)

Pillow basalts, belonging to Late Cretaceous Yüksekova Complex are extensivelly exposed around Elazıg in Eastern Turkey. This unit is a part of southeastern Anatolian ophiolite belt and the Southern Branch of the Neotethys. It represents the products of intra- oceanic subduction volcanism and mainly comprises pillow lavas, dykes and associated with sedimentary rocks. Pillow lavas and feeder dykes are basaltic in composition and subdivided in two geochemically distinct groups. Almost all of them are intruded by carbonate, silica or iron oxide-filled fractures. They are generally gray, red, purple or yellowish green, dark green in color. Thickness of shell of pillow varies between a few mm to 1 cm. Average density of them is 2.69 g/cm³, and they have average porosity of 5%. Pores with oval structure which is relativelly indicative of high viscosity reach up a few mm to 1 cm. They are filled by amygdules such as silica, calcite, chlorite, zeolites that indicate alteration by sea water.The abundance and extremely coarse size of amygdules in these rocks might signify the presence of a shallow marine environment.Also, there is no clear difference in abundance and type of amygdule observed at group 1 and group 2. Flakes of chloriteform an interpillow matrix are found mostly between of pillows. In according to the frequency distributions of pillowed basalts, samples of group 1 have a more uniform rate of rounding, while samples of group 2 represent more variable rate of rounding. The long and short axis sizes of pillow basalts vary from a few centimeters to meters. Varying sizes of the pillow basalts indicate an effusion environment long-lasting or with multi-stage. The main magmas of the examined pillow basalts, belonging to Late Cretaceous Yüksekova Complex, similar to each other because of the absence of a significant difference in compositions and morphologies of both groups.