A reliable lithospheric thermal structure model of the South Yellow Sea in East Asian continental margin based on radiogenic heat production measurements

The thermal state of lithosphere provides the basis for the study of tectono-thermal evolution and geodynamic processes. The South Yellow Sea (SYS) has no available lithospheric heat production rate (HPR) and thermal structure data so far. The continuous Quaternary‒Silurian cores obtained from the CSDP-2 borehole, together with high-quality seismic wave velocity data, provide an excellent opportunity to study the HPR and thermal structure of the SYS within the East Asian continental margin (EACM). The results show that the HPRs of unconsolidated sediments, carbonate rocks , clastic rocks , and mixed rocks, are 1.21, 0.45, 2.47, and 1.87 μW m −3 , respectively. The HPR of carbonate rocks is much lower than that of clastic rocks, while increases in organic matter content greatly increased the HPR of clastic rocks. The first reliable heat generation profile based on measured data is established in the South Yellow Sea. The HPR of Sinian‒Ordovician strata is 0.22–0.29 μW m −3 , while the HPRs of Upper Ordovician‒Silurian, Devonian‒Lower Carboniferous, Upper Carboniferous, Permian , Lower Triassic, and Neogene‒Quaternary strata are 2.01, 1.90, 0.62, 2.98, 1.95, and 1.21 μW m −3 , respectively, which are mainly controlled by the sedimentary environment and lithofacies . The radiogenic heat production within the crust is 0.88 μW m −3 . The crustal contribution to surface heat flow is 29 mW m −2 , accounting for approximately 43 % of total surface heat flow. The contribution of crustal radiogenic heat production to surface heat flow is commonly considered to increase from the edge of the East Asian continent to the interior. The SYS has the unique characteristics of a relatively low crust‒mantle boundary temperature and thick thermal lithosphere, which has an inherited feature of the massive overthrust foreland sedimentation in the northern part of the SYS related to the collision of the Yangtze carton and North China plate. • U, Th, and K content of 302 core samples from the South Yellow Sea were analyzed. • We calculated the heat production rates (HPR) of all strata from the CSDP-2 cores. • We modeled crustal the contribution to surface heat flow in the South Yellow Sea.