Meso–Cenozoic lithospheric thermal structure in the Bohai Bay Basin, eastern North China Craton

The Bohai Bay Basin is a region where part of the North China Craton has been thinned and destroyed. It has experienced two periods of crustal thinning that occurred during the Cretaceous and Paleogene, but investigations of its Mesozoic and Cenozoic lithospheric thermal structure are limited. Therefore, in this study, the distributions of mantle heat flow, crustal heat flow, and Moho temperatures during the Meso–Cenozoic are calculated based on analyses of the thermal history of the Bohai Bay Basin. The results indicate that the ratio of mantle heat flow to surface heat flow peaked during the late stages of the early Cretaceous and during the middle to late Paleogene. The corresponding mantle heat flow was more than 65% of the surface heat flow. Moho temperatures reached three peaks: 900–1100 °C in the late stages of the early Cretaceous; 820–900 °C in the middle to late Paleogene; and (in the Linqing Depression, Cangxian Uplift, and Jizhong Depression) 770–810 °C during the early Neogene. These results reveal that the Bohai Bay Basin experienced significant geological change during the Cretaceous, including the transformation of lithospheric thermal structure from “cold mantle and hot crust” before the Cretaceous to “hot mantle and cold crust” after the Cretaceous. The results also indicate that the basin experienced two large-scale rifting events. Therefore, this work may provide the thermal parameters for further investigations of the geodynamic evolution of eastern China.