Cryogenian–Cambrian tectono-sedimentary evolution, paleoclimate and environment effects, and formation of petroleum resources in the Tarim Block

Abstract

Neoproterozoic tectonic evolution, magmatic activities, and sedimentary sequences are fundamental in understanding the transition from the dispersing of Rodinian continents to the assemblage of Gondwana and simultaneously supply crucial evidence for the global climate–environment change, i.e., from the Snowball Earth to a habitable Earth. In this contribution, we comprehensively synthesize the well-preserved Cryogenian–Cambrian sequences, multiple-phased magmatic activities, paleoclimate and environment in the Tarim Block of northwestern China to sketch a tectonic-sedimentary process from the breakup of Rodinia to the assemblage of Gondwana. We address the coupling between tectonic evolution process, glacial–interglacial cycles, paleoclimate and environment changes, and the formation of petroleum resources. In this study, we establish the stratigraphic frameworks in Kuruktag, Aksu, Tieklik areas in the northeast, northwest, and southwest of the Tarim Block, respectively. We review the differential geodynamic mechanisms and development processes of rifts in two discrete terranes, namely the North Tarim Terrane and South Tarim Terrane, of the Tarim Block to reconstruct the tectonic evolution process of Tarim during the Cryogenian–Cambrian interval and further decipher its control on the paleogeographic framework. The transition from extensional to compressional conditions during the early Cryogenian to Cambrian, combined with multiple phases of magmatic and glaciations, led to the three-stage evolution of sedimentary filling styles. We also document the evolution of glacial–interglacial cycles and how it impacts the paleoclimate and environment, sedimentary sequences, and the evolution and preservation of early life. The formation of organic-rich black mudstone/shale is attributed to the increasing nutrients in marine water and blooming of life in a warm-humid climate during interglacial periods; and thus, we propose the formation models of three favorable ancient petroleum source rocks in response to different tectono-sedimentary evolution stages and further estimate their quality, distribution, and resource potential. This review provides an improved understanding of the Cryogenian–Cambrian tectono-sedimentary evolution in the Tarim Block and its effects on the formation of ancient petroleum source rocks. It sheds insights into hydrocarbon accumulation theories and exploration strategies in ultra-deep ancient strata.