论文部分内容阅读
中国东南大陆晚侏罗世地层普遍缺失,仅零星见于个别地区,香港新界东北的荔枝庄组即为其一。荔枝庄组出露于香港世界地质公园沉积岩园区的荔枝庄地区,自下往上由火山岩—沉积岩—火山岩组合而成,沉积岩中发育大型包卷层理和滑塌构造等典型沉积构造,是香港地区最具代表性的晚侏罗世火山—沉积岩系。通过实测地层剖面研究,确定其成岩过程大体上可划分为早期普林尼式火山爆发、中期破火山口湖相沉积和晚期普林尼式火山爆发三个阶段,以湖相沉积作用为主、火山喷发作用为辅;受晚期火山岩浆活动的影响,沉积岩层普遍发生硅化或炭化。荔枝庄组独特的岩石组合与形成的古地理环境,为探讨中国东南大陆中生代火山活动—沉积作用方式与成岩过程,提供了难得的研究实例。
The Late Jurassic strata in southeastern China are generally missing, with only sporadic occurrences in some areas. The Litchi Chuang Formation in northeast New Territories, Hong Kong is one of them. The Lai Chih Chuen Formation was exposed in the Lai Chih Chuang area in the Sedimentary Rock Park of the World Geopark in Hong Kong. It is composed of volcanic rocks - sedimentary rocks and volcanic rock from bottom to top, and is characterized by large-scale sedimentary bedding and slump structures in sedimentary rocks. The most representative Late Jurassic volcanic-sedimentary rock series. Based on the measured stratigraphic profile, the diagenetic process can be generally divided into three stages: early Pliny volcanic eruption, mid-term caldera lacustrine deposition and late Pliny volcanic eruption, with the lacustrine facies as the main deposit, Complementary to volcanic eruptions, silicification or carbonization of sedimentary rocks occurs generally due to late volcanic activity. The unique rock assemblages and paleogeographic environments of the Lai Chih Chuen Formation provide a rare case study for exploring the Mesozoic volcanic activity-sedimentation modes and diagenesis processes in the southeastern China.