Cretaceous–Cenozoic regional stress field evolution from borehole imaging in the southern Jinzhou area, western Liaoning, North China Craton

Abstract

The Mesozoic Yanshanian Movement affected the tectonic evolution of the North China Craton (NCC). It is proposed that Mesozoic cratonic destruction peaked ~125 Ma, possibly influenced by subduction of the western Pacific Plate beneath the Euro-Asian Plate in the Early Cretaceous. The southern Jinzhou area in the eastern block of the NCC preserves clues about the tectonic events and related geological resources. Studies of the regional stress field evolution from the Cretaceous to the Cenozoic can enhance our understanding of the tectonics and dynamics of the NCC. Borehole image logging technology was used to identify and collect attitudes of tensile fractures from 11 boreholes; these were subdivided into four groups according to dip direction, i.e., NNW-SSE, NWW-SEE, W-E and NE-SW. The development of these fractures was controlled primarily by the regional tectonic stress field; temperature, lithology, and depth contributed to some extent. In 136–125 Ma in the Early Cretaceous, the area was characterized by extension that was oriented NNW-SSE and NWW-SEE; from 125–101 Ma the extension was oriented W-E; after 101 Ma it was NE-SW. This counterclockwise trend has persisted to the present, probably related to oblique subduction of the Pacific Plate, and is characterized by ongoing extension that is nearly N-S-oriented and NEE-SWW-oriented compression.