Geological Characteristics and Tectonic Evolution of the Qingyang-Etuoke Paleo-Uplift in the Ordos Block
The geological characteristics,formation,and evolutionary processes of the Qing-E(Qingyang-Et-uoke)Paleo-uplift in the southwestern Ordos Block are crucial for understanding the geodynamics,paleoenvir-onment,and oil and gas exploration along the southwest margin of the North China Plate.We investigated the formation timing,tectonic evolution,and geodynamics of the Qing-E Paleo-uplift in the Ordos Basin using seis-mic,well,and log data.The results indicate that three unconformities can be identified based on the seismic data:between the Upper Paleozoic and the underlying strata,between the Neoproterozoic-Paleozoic and the Cambrian,and between the Cambrian and the Ordovician.Synsedimentary normal faults were observed in the Cambrian and Ordovician,with seismic facies characterized by onlap at the base and truncation at the top in both the Cambrian and Ordovician strata.The well data indicated that the thickness of the Middle Cambrian re-mained consistent,while the Upper Cambrian and Lower Ordovician thinned and eventually disappeared,being unconformably overlain by the Middle Ordovician.The Upper Ordovician developed to a limited extent.The disappearance of the Middle Cambrian and Middle Ordovician was due to erosion,while the sedimentation process of the Middle Cambrian was continuous.We concluded that the Paleo-uplift was formed during the Ear-ly Paleozoic.The prototype of the Paleo-uplift was formed during the Early Cambrian,influenced by the pre-ex-isting framework.By the Mid-Late Cambrian,the uplift activity of the Paleo-uplift gradually weakened.From the end of the Late Cambrian to the Early Ordovician,the uplift of the Paleo-uplift led to the erosion of certain strata,including the Upper Cambrian and Lower Ordovician.However,during the Middle Ordovician,the Pa-leo-uplift gradually transitioned into a submarine uplift.By the Late Ordovician,the Paleo-uplift experienced significantly uplift and was ultimately completed under the influence of the Caledonian movement.The geody-namics of the Qing-E Paleo-uplift was closely linked to the tectonic setting and evolution of the western and southern margins of the North China Craton during the Early Paleozoic.This study provides theoretical support and serves as a reference for determing the early Paleozoic tectonic setting in the southwest margin of the North China Plate,as well as for oil and gas exploration in the Qing-E Paleo-uplift.
万方数据
维普
