Lead isotopic composition of rutiles from the Chinese continental scientific drill (CCSD) hole and its genetic significance for the superlarge rutile deposit in Maobei, Jiangsu Province

The central orogenic belt in China, which extends from the Kunlun Mountains in the west to the coast in the east, has experienced a complextectonic evolution.Based on the Chinese Continental Scientific Drill (CCSD) Hole, this paper reports that the Pb isotopic composition of rutiles selected from surface, from 350m depth and from 500m depth in core are variable, with high content of radiogenic Pb at the middle and later stages of the step-by-step leaching process. This suggests that the rutile-bearing eclogites might have experienced two times of subduction and exhumation.