BURIAL VS. TECTONIC ORIGIN OF THE VEINS IN THE TURKISTAN REGION

Abstract

This thesis work aims to investigate the origin of the calcite veins in the Bolshoi Karatau region within the Baktysai Formation unit. The workflow of this research project is structured in a way to answer the following: “Are the dominant sets of veins in the Bolshoi Karatau of burial or of tectonic origin?”. With the application of structural geology knowledge and tools such as scanline surveying and stereographic projection analysis, two dominant sets of veins were identified. Veins of set 1 are oriented parallel to the fold axis, while veins of set 2 are oriented perpendicular to the bedding. Veins of set 2 are recognized to be the youngest and dextrally offsetting the veins of set 1. Other than scanline surveying, orientations of the randomly picked veins of the whole Bolshoi Karatau region were measured, and proved that the dominant sets revealed within the outcrops of scanlines are representative of the region. Moreover, to understand the origin of these vein sets, a detailed study of exposed anticlines and study of the tension gashes was conducted. Stereonet projection of the anticlinal zones revealed that the veins of set 2 formed syn-folding. The models of tension gashes revealed that the veins of set 1 are also of tectonic origin, because patterns of tension gashes were not dependent on bedding orientation, thus supporting the tectonic stress regime factor. This study is also considered as a small contribution to the TengizChevroil company project to study the fracture systems of the carbonate platform of the Tengiz oil field.