Combined with field studies, microscopic observations, and EBSD fabric analysis, we defined a possible Early Cretaceous metamorphic core complex （MCC） in the Wulian area along the Sulu orogenic belt in eastern China. The MCC is of typical Cordilleran type with five elements： （1） a master detachment fault and sheared rocks beneath it, a lower plate of crystalline rockswith （2） middle crust metamorphic rocks, （3） syn-kinematic plutons, （4） an upper plate of weakly deformed Proterozoic metamorphic rocks, and （5） Cretaceous volcanic-sedimentary rocks in the supradetachment basin. Some postkinematic incursions cut across the master detachment fault zone and two plates. In the upper plate, Zhucheng （诸城） Basin basement consists of the Proterozoic Fenzishan （粉子山） Group, Jinning period granite （762–834 Ma）. The s u pr a de tac hme nt ba sin a bo ve the Proterozoic rocks is filled with the Early Cretaceous Laiyang （莱阳） （~135–125 Ma） and Qingshan （青山） groups （120–105 Ma）, as wellas the Late Cretaceous Wangshi （王氏） Group （85–65 Ma）. The detachment fault zone is developed at the base and margin of the superposed basin. Pseudotachylite and micro breccia layers located at the top of the detachment fault. Stretching lineation and foliation are well developed in the ductile shear belt in the detachment faults. The stretching lineation indicates a transport direction of nearly east to west on the whole, while the foliations trend WNW, WSW, and SE. Protomylonite, mylonite, and ultramylonite are universally developed in the faults, transitioning to mylonitic gneiss, and finally to gneiss downward. Microstructure and quartz preferred orientation show that the mylonites formed at high greenschist facies to low greenschist facies as a whole. The footwall metamorphic rock series of the Wulian MCC are chiefly UHP （ultrahigh pressure） metamorphic rocks. Syntectonic rocks developed simultaneously with the Wulian MCC detachment and extension. Geo
The Huimin（惠民） depression is a third-level tectonic element of the Bohai（渤海） Bay basin in eastern China.The central uplift belt is the most important oil and gas accumulation zone in the depression,but the lack of adequate geological studies in the area has greatly hindered exploration and development.In this article,using seismic data,fracture mechanics,and a combination of data on fault growth indices and fault throws,we present an analysis of tectonic activity in the central uplift belt and adjacent regions.The amount of extension is calculated along balanced N-S cross-sections,along with the thickness of strata eroded from the fourth,third,and second members of the Shahejie（沙河街） Formation（Es4-Es2） in the uplift belt,by analyzing porosity and stratigraphic correlations.In addition,uplift features are described,and their timing and processes of formation are analyzed and dis-cussed.The results indicate that strike-slip and extensional tectonic movements coexisted,with the effects of the latter most obvious.The spatial and temporal nature of the extensional move-ments is varied：fault activity during the period Ek-Es4 was the strongest on the northern Ningnan（宁南） fault,and activity in the western part of the area was stronger than that in the east,which in turn was stronger than that in the central region;during Es3-Es2,the strongest fault movements were along the eastern part of the middle Linyi（临邑） fault,and activity in the western part of the area was rela-tively weak,whereas in the mid-west it was the strongest.The extensional movements were a response to the activity of the faults.The sediments in the lower part of the fourth member of the Shahejie For-mation（Es4x） show that Es4 was the time when the central belt first began to be uplifted strongly.Uplift was uneven during the Paleogene：the western part of the area was uplifted continuously,while the mid-eastern area underwent alternating periods of uplift and subsidence.During the Paleogene,a number of d
