Some Stratigraphic and Tectonic Characteristics of the Area Around Hınıs (Southeast of Erzurum)

Abstract

The study area is situated between Hınıs-Tekman and Karayazı southeast of Erzurum. The aim of this study was to investigate some geological characteristics of the region. The rock units constituting the lowermost sections of the study area consist of alternating gneiss, amphibolite, schist and marble, from bottom to top, are exposed beneath the ophiolitic complex, as a tectonic window. The ophiolitic complex consists essentially of diabase, gabbro, and locally of serpentinite and peridotite. The acidic intrusions cut both the metamorphics and ophiolitic complex. The rocks ranging from Maestrichtian to Pliocene in age are made up of regular alternations of transgressive and regressive sequences, and rest upon the older rocks, unconformably. The study area became a piece of land during the Middle(?) — Upper Miocene. The Oligocene sequence of the sedimentary cover contains thin intercalations of andesitic basalt. In the Miocene-Pliocene sequence of the cover, firstly, volcanic rocks varying from dacite to andesite in composition, and then, in turn, andesitic basalt and basaltic pyroclastic rocks and lavas took place. Overthrusts which are of pre-Maestrichtian and Late Eocene age were also defined in the study area. Along the Late Eocene overthrusts the ophiolitic complex has thrusted over the Eocene rocks which are situated to the south of the complex. Parallel and oblique fault zones which have NW-SE striking right lateralslips and NE-SW striking left lateral-slips were developed, as well as approximately E-W trending folds and overthrusts under the control of compressional tectonic regime, during the Late and post-Miocene. In addition, some other structures have been also developed in the Plio-Quaternary formations lying within both of two fault zones, by the effects of approximately E-W trending compressional forces.