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早三叠世扬子地台位于特提斯东北缘,研究者根据大量地质证据和模拟实验证实该时期巨型季风强度最大,且控制了整个泛大陆和周边海域的气候循环。笔者于川西北广元上寺剖面下三叠统中发现一套保存完好的风暴岩,其发育于飞仙关组下部,风暴沉积特征明显,风暴侵蚀构造、风暴撕裂构造和层理构造发育;根据沉积构造、岩石性质等识别了Sa-Sb-Sc、Sb-Sd、Sa-Sc-Sd三种序列组合(Sa-滞留砾屑沉积,Sb-粒序层理,Sc-丘状交错层理,Sd-均质层理)。早三叠世研究区处于有利于保存风暴沉积的浅海环境,风暴岩的形成、发展与特征对古气候研究有重要意义。我们认为上寺地区(乃至扬子地区)的风暴沉积,可能是最强盛的季风循环影响的结果;而P/T界线生物大量灭绝后缺乏潜穴生物的背景使风暴岩得以保存。
The Early Triassic Yangtze platform is located on the northeastern margin of Tethys. Based on a large amount of geological evidence and simulation experiments, the authors confirmed that the monsoon was the strongest in this period and controlled the climate cycle throughout the entire continent and the surrounding sea. A well-preserved storm rock was found in the Lower Triassic of the Guangyuan Shangsi Section in the northwest of Sichuan Province. It developed in the lower part of Feixianguan Formation, with obvious storm deposits, storm erosion structure, storm tear structure and bedding structure development. Based on the sedimentary structure and rock properties, Sa-Sb-Sc, Sb-Sd and Sa-Sc-Sd sequences are identified as Sa-Retained gravel sediments, Sb- , Sd-homogeneous layering). The Early Triassic study area is in a shallow sea environment conducive to the preservation of storm deposits. The formation, development and characteristics of storm rocks are of great significance for paleoclimate research. We believe that the storm deposits in the Shangsi area (and in the Yangtze region) are likely to be the result of the most powerful monsoon circulation. The absence of the source rocks of the P / T boundary after massive extinction has saved the storm rock.