Zircon U-Pb and Hf Isotopic Studies of Basement Gneiss and Overlying Meso-Neoproterozoic Sedimentary Rocks from the Changping Area, Beijing, and Their Geological Implications
摘要
///Zircon LA-ICP-MS U-Pb and Hf isotopic studies of the Neoarchean basement gneiss of the Miyun Group and overlying Meso-Neoproterozoic sandstones of the Changzhougou Formation of the Changcheng System and Changlongshan Formation of the Qingbaikou System from the Yan-Liao aulacogen in the Changping area, Beijing, are carried out in order to investigate the sedimentary and crustal evolution of the North China Craton (NCC). The available data suggest that the age distribution and sedimentary evolution of the Meso-Neoproterozoic sedimentary rocks are closely related to the rifting process. As the rifting developed, the provenance for the upper part of the Changzhougou Formation includes both of the basement and Paleo-Mesoproterozoic rocks, and the Changlongshan Formation contains more Paleo-Mesoproterozoic components, showing an increasing trend of the younger components in the Meso-Neoproterozoic sedimentary rocks from bottom to top.