川北米仓山隆起构造－热演化特征

本文基于实测锆石(U-Th)/He和磷灰石裂变径迹年龄的联合热史模拟明确了米仓山隆起自新元古代以来的构造-热演化史。米仓山隆起前寒武系样品锆石(U-Th)/He年龄和磷灰石裂变径迹年龄分别为190~138 Ma和106.1~120.6 Ma，均小于地层年龄或成岩结晶年龄，有效地记录了早期热信息。热史模拟结果表明米仓山隆起自新元古代以来主要经历了早侏罗世—早白垩世和晚中新世至今两期快速冷却事件，分别与扬子-华北板块碰撞和印度-欧亚板块碰撞的东扩作用有关，而白垩纪—早中新世的缓慢冷却过程则与当时的古夷平面发育有关。本文不仅丰富完善了川北地区构造-热演化成果，而且对于该地区下一步油气勘探具有重要的指导意义。

Tectono-thermal evolution of the Micangshan Uplift in the northern Sichuan Basin

The tectono-thermal history of the Micangshan Uplift since the Neoproterozoic was determined in this study based on the combined thermal simulation of the measured zircon (U-Th)/He and apatite fission track ages. The zircon (U-Th)/He ages and apatite fission track ages of the Precambrian samples in the Micangshan Uplift are 138-190 Ma and 106.1-120.6 Ma, respectively. These ages are lower than the corresponding stratigraphic ages or the diagenetic crystallization age, indicating that they effectively record the thermal information in the past. Thermal history modeling results show that the Micangshan Uplift since the Neoproterozoic experienced two rapid cooling events that occurred in Early Jurassic-Early Cretaceous and since late Miocene. They are respectively related to the collisions of the Yangtze-North China plates and India-Eurasia plates, whereas the slow cooling events during the Cretaceous-early Miocene were related to the ancient planation surface. According to the reconstructed burial and thermal history, the source rocks of the Lower Cambrian Qiongzhusi Formation in the Micangshan Uplift entered a high-overmature stage in the Late Triassic due to the high temperature (180-200℃) burial process. This study provides new insights for the tectono-thermal evolution and hydrocarbon accumulation, which are important for guiding further oil and gas exploration in the northern Sichuan Basin.