Depositional Settings and Enrichment Processes of Extraordinarily High Organic Matter Content of Black Shale in the Talung Formation of the Upper Permian: A Case Analysis of the Kaijiang–Liangping Trough, Southern China

ABSTRACT The black shale strata in the Talung Formation of the Upper Permian is a new target for marine shale gas exploration breakthroughs in South China. Through petrological and elemental geochemical analyses of black shales in the Talung Formation, the sedimentary environment during the late Wuchiapingian to Changhsingian stage was clarified, and an enrichment model of extraordinarily high organic matter (EHOM) was established. The shales in the Kaijiang–Liangping Trough are mainly composed of siliceous calcareous shales, with a total organic carbon content ranging from 5.45% to 20.15%, and the kerogen type is predominantly Type II 1 . During the deposition of the Talung Formation, the margin of the Kaijiang–Liangping Trough was characterised by a shallow to semi‐deep water shelf environment, with a warm, humid climate and anoxic reducing water conditions. The water at the margin of the marine trough was slightly turbulent, with a low degree of stagnation. The primary productivity proxies established using trace elements Cu, Zn, and Ni reveal a high level of primary productivity in the water during the Late Permian. The widespread upwelling activity and suitable terrigenous clastic input brought abundant nutrients into the waters, significantly enhancing primary productivity. However, hydrothermal and volcanic activities had no significant contribution to primary productivity. Thus, the high primary productivity brought by upwelling and terrigenous clastic input significantly promoted the production of EHOM, and the reducing water conditions facilitated the preservation of EHOM. The excellent production and favorable preservation jointly ensured the accumulaiton of EHOM in the Talung Formation shale of the Kaijiang‐Liangping Trough.