婆罗洲东北部古太平洋俯冲记录：Baliojong大洋板块地层碎屑物源和年代学研究

古太平洋板块由于俯冲作用已经消亡殆尽，恢复其演化历史变得相对困难。东南亚新生代构造-古地理格局的变迁导致古太平洋俯冲记录的保存和研究程度较低，特别是婆罗洲东北部大洋板块地层与古太平洋之间的联系尚不明确。本项目拟对该地区Baliojong大洋板块地层的多套浊积岩开展碎屑物源和年代学研究，综合运用地球化学、矿物学、锆石U-Pb-Hf及金红石U-Pb同位素来限定其沉积时代和组成成分，并与婆罗洲-南海地区同时代弧前沉积-增生楔前人研究成果进行对比，恢复古太平洋俯冲背景下该地区源汇系统演化，探究Baliojong浊积岩记录的古大洋板块俯冲时间和上覆板块古地理信息。研究成果有望深化对婆罗洲-南海地区早期地质历史的认识，为重建晚中生代古太平洋俯冲体系提供可靠证据。

Reconstructing the evolutionary history of the Paleo-Pacific plate is relatively difficult because it had been nearly lost to subduction. Records of the Paleo-Pacific subduction in Southeast Asia have been poorly preserved and investigated due to the change in the tectonic-paleogeographic framework over the Cenozoic, and in particular, the relationship between the Ocean Plate Stratigraphy in Northeast Borneo and the Paleo-Pacific remains unclear. This study is proposed to conduct detrital provenance and geochronological analyses on multiple turbidite intervals of the Baliojong Ocean Plate Stratigraphy in this region, and an integration of geochemistry, mineralogy, zircon U-Pb-Hf and rutile U-Pb isotopes can constrain their depositional ages and compositions. By comparing with previous research findings of the contemporary forearc-accretionary deposits from the Borneo-South China Sea region, this study attempts to restore the source-to-sink evolution of the region in the context of the Paleo-Pacific subduction, and explore the information on the subduction timing of the paleo-oceanic plate and the paleogeography of the overriding plate recorded in the Baliojong turbidites. The results are expected to deepen the understanding of the early geological history of the Borneo-South China Sea region, and provide reliable evidence for the reconstruction of the Late Mesozoic subduction system of the Paleo-Pacific.