Jurassic Deposits Heavy Mineral Evolution Characteristics of Jurassic Deposits in the Southeastern Margin of the Junggar Basin and its Response to Bogda Mountains Uplift

Key words: 
• Junggar Basin /
• southeastern margin /
• Jurassic /
• heavy minerals analysis /
• Bogda Mountains /
• uplift

Abstract: Junggar basin is one of the largest petroliferous basins in China, although a series of oil and gas fields had been found in the south of the basin, the oil-gas exploration in the fore mountain belt of Bogda Mountain did not make great breakthroughs. The reason may be associated with the few awareness of the evolution of the Bogda Mountain to control, restrain the evolution of the late peripheral sags and the hydrocarbon generation and the basin formation. The conservative fragmentary materials in sedimentary basins had recorded the lithosphere features of the orogenic belts at the margin of the South China block and kinetics characterization of basins during the sedimentary evolution. At the same time, as sedimentary heavy minerals were very stable and they had been participating in this long and complicated geological processes, which could provide the important information to the source rocks. Thus, in this text, based on the mineral petrology characteristics of heavy minerals, such as roundings, content changes, combination features and the different heavy mineral indexes, to study the uplift processes of Bogda Mountain in the period of Jurassic, which could provide strong evidence that Bogda Mountain uplifted in Toutunhe Formation of Middle Jurassic. Moreover, according to the features of heavy minerals, the tectonic evolution stages of Bogda Mountain during Jurassic period were divided into two parts:1) from early Jurassic to the late period of middle Jurassic, the tectonic evolution was relatively stable, and 2) from the late period of middle Jurassic to late Jurassic, tectonic uplifting was strong. In addition, combined with the previous research results such as tectono-thermochronology, U-Pb age and paleocurrent, we considered that the provenances of Bogda area were from Kalameili Montain during early Jurassic to the late period of middle Jurassic and Bogda Mountain during the late period of middle Jurassic to late Jurassic. And that, in the later period, the Bogda Mountain had been uplifted.