Regional tectonic stress field evolution based on multi-source stress data—a case study in the Jinzhou area, North China Craton

Abstract

Regional tectonic stress fields are key crustal stress elements that drive tectonic movements and associated with the evolution of regional tectonics, as well as the formation, preservation, and development of geological resources. The evolution of the regional tectonic stress field of the Jinzhou area, which is located in the eastern block of the North China Craton (NCC), may provide a deeper understanding of the tectonics of western Liaoning and the NCC. In this work, borehole image logging technology and focal mechanism solutions were used to invert the paleo and present regional tectonic stress fields. Four groups of tensile fractures in the southern Jinzhou area were identified via the borehole televiewer, and the azimuths of these fractions were NNW-SSE, NWW-SEE, nearly W-E, and NE-SW in sequence. Focal mechanism solutions showed that the stress states of the area were normal fault and strike-slip, thereby revealing that the southern Jinzhou area is undergoing NEE-SWW-oriented compression and nearly N-S-oriented extension in accordance with the strike-slip mechanism. From the Early Cretaceous to the present, the direction of the regional extensional stress in the southern Jinzhou area has evolved in a counterclockwise and sequential manner from NNW-SSE to NWW-SEE, W-E, NE-SW, and near-N-S; moreover, the regional tectonic mechanism has transitioned from extension to extension-strike-slip to strike-slip.