Geochemistry and geochronology of the Early Cretaceous acid volcanic rocks from the Jintaizi Basin, northern Hebei Province, China: Implications for the destruction of the North China Craton
Qi Guowei1, Zhang Jinjiang1, Wang Meng1, Liu Jiang1,2, Wang Xiaoxian1,3
1. MOE Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871;
2. Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037;
3. The Institute of Crustal dynamics, China Earthquake Administration, Beijing 100085
The North China Craton (NCC) was severely destroyed during the Mesozoic. Although the main period of this destruction has been well established, the initial time of the destruction remains poorly understood. In this work, we analysed the tectonic setting of the Jintaizi Basin in northern Hebei Province of China, and determined the age and analysed chemical compositions of the volcanic rocks from the basin. The data was used to better constrain the time of the onset of the destruction of the NCC. Our structural analysis showed that the Jintaizi Basin was a NNE-striking half-graben controlled by normal faults on its eastern margin, whereas the fillings overlapped on to the basement on its western margin. The basin fills include detrital sediments and volcanic rocks, which constitute four formations. The lowest Houcheng Formation and the uppermost Jiufotang Formation are both composed mainly of detrital sediments. The Middle Baiqi Formation and the Taobeiying Formation comprise mainly thick rhyolite strata and rhyolitic tuff lava, locally interlayered with andesite and volcaniclastic rocks. Geochemical data indicated that the acid volcanic rocks were most likely derived from the crustal melting. U-Pb dating of zircon showed that the massive felsic volcanic magma began to erupt at about 145 Ma, which represented significant destruction and thinning of the lithosphere under the northern Hebei area during that time. We conclude, therefore, that the destruction of the northern margin of the NCC might have started by the turn of the Jurassic and the Cretaceous or earlier.
. Geochemistry and geochronology of the Early Cretaceous acid volcanic rocks from the Jintaizi Basin, northern Hebei Province, China: Implications for the destruction of the North China Craton[J]. Chinese Journal of Geology, 2015, 50(4): 1134-1153.