Characteristics of Late Hercynian paleokarsts in Akekule Uplift, Tarim Basin

Based on 3D seismic and drilling data, combined with modern karstology, this paper discussed the characteristics of Late Hercynian paleokarsts in the Yuqi and Lunan areas of the Akekule Uplift, the Tarim Basin. Study results showed that the Yuqi area was a peneplain, developing karst landforms such as grikes and depressions, which were controlled by faults. The surface water system featured multiple periods. The formation of peneplain in the Yuqi area was closely related to tectonic position, stratum attitude, paleoclimate and the base level of erosion. The Lunan area rose higher than the Yuqi area in the Late Hercynian. Some peak clusters remained since peneplanation was not complete. Large peak cluster and depression karst landforms formed in the Early Hercynian, and groundwater systems were well developed, which was different from the situation in the Late Hercynian. Fracture and cave reservoirs related to the Late Hercynian paleokarsts were mainly distributed along fault zones in the Yuqi area. They were widespread in the Lunnan area, and were controlled by the base level of erosion, fault and peneplanation degree.