沉积学报2025，Vol.43Issue(5)：1665-1678,14.DOI:10.14027/j.issn.1000-0550.2025.055
深时高频古风暴沉积特征与成因机制研究
Study on Sedimentary Characteristics and Genesis Mechanism of Deep-Time High Frequency Palaeo-Storms:An example from the Devonian Ganxi Formation in the Longmenshan area
摘要
Abstract
[Objective]The Devonian Ganxi Formation in the Longmenshan area developed abundant storm deposi-tion records,making it is an excellent location for studying the characteristics of paleo-storm deposition,but there is a lack of systematic research on the changing trend of high-frequency storm deposition,particularly on the possible genesis mechanism of deep-time paleo-storm development.[Methods]In this study,two field profiles,Anlecun and Yingzuiyan,in Ganxi village,Guixi town,Beichuan Qiang Autonomous County,Longmenshan area,which are well exposed in the Ganxi Formation,were selected for identifying and describing in detail the characteristics of high-frequency storm deposition developed within the sections.Storm frequency and abundance curves reflecting the frequency and intensity of changes in storm activities were established to analyze the changing pattern of storm deposi-tion intensity.[Results](1)Two types of storm depositional signatures were developed in the Devonian Ganxi Forma-tion in the Longmenshan area:storm depositional structures and biological shell enrichment layers,with the former including storm erosion structures and wave structures,and the latter including three types:storm-wave scouring and transporting,storm and bumping,and opportunistic species explosion.(2)Spectral analysis of storm abundance curves suggests that the 100-kyr eccentricity cycle was developed in the storm deposits of the Devonian Ganxi Forma-tion in the Longmenshan area.[Conclusions](1)The 100-kyr eccentricity cycle is the main orbital cycle that caused climate variations and changes in storm frequency and intensity in the Devonian Ganxi Formation.(2)Storm activi-ties were controlled by a short eccentricity cycle of 100 kyr,and the amount of sunshine brought by the high eccentricity promoted the movement of the Intertropical Convergence Zone(ITCZ),affecting the monsoon circulation and precipitation changes.The Longmenshan area,which was located on the South China Plate,was in the path of the ITCZ during the Devonian,and the heat and evaporation of seawater provided by warming during the period of high eccentricity also promoted the formation of tropical cyclones,which in turn contributed to the occurrence of storms at a high frequency.关键词
高频风暴沉积/天文轨道旋回/成因机制/泥盆系,龙门山地区Key words
high frequency storm deposition/astronomical orbital cycle/genesis mechanism/Devonian/Longmenshan area分类
天文与地球科学引用本文复制引用
李凤杰,王佳,陈政安..深时高频古风暴沉积特征与成因机制研究[J].沉积学报,2025,43(5):1665-1678,14.基金项目
国家自然科学基金项目(42372142)National Natural Science Foundation of China,No.42372142 （42372142）
