古生代陆相盆地中的17万年天文周期  

The 170 kyr Astronomical Cycles in the Paleozoic Terrestrial Basin

作　　者：李玉寅 黄何 高远[1,4] 成虎[1] 黑晨露 梁爽 王成善 LI YuYin;HUANG He;GAO Yuan;CHENG Hu;HEI ChenLu;LIANG Shuang;WANG ChengShan(School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China;Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Chengdu University of Technology),Chengdu 610059,China;State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences(Beijing),Beijing 100083,China)

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]成都理工大学沉积地质研究院,成都610059 [3]油气藏地质及开发工程国家重点实验室(成都理工大学),成都610059 [4]中国地质大学(北京)生物地质与环境地质国家重点实验室,北京100083

出　　处：《沉积学报》2024年第1期39-51,共13页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(41972096)。

摘　　要：【目的】米兰科维奇周期通过调控地球天文轨道参数来影响地球气候系统和有机碳埋藏。除通过线性过程调控气候系统的常规周期外,还存在通过一系列“非线性”正负反馈进程调控气候系统的“非常规”天文周期,如17万年斜率振幅调制周期。先前研究已证明17万年天文周期对中新生代地球中高纬度有机碳埋藏具有调控作用,然而由于缺乏准确的天文解和高分辨率的地质记录,17万年信号在古生代鲜有报道。【方法】对准噶尔盆地早二叠世芦草沟组的总有机碳含量和自然伽马测井数据进行旋回地层学分析,认为芦草沟组保存了短偏心率、斜率、岁差周期信号。【结果】根据短偏心率周期进行了天文调谐,结果显示芦草沟组沉积持续时间约为2.8 Myr,沉积速率估算为9.1 cm/kyr。除常规周期外,17万年周期信号也在去趋势数据序列和斜率振幅调制曲线中被发现。【结论】对古生代陆相地层中的17万年天文周期进行系统探讨,基于强烈的斜率信号,推测该17万年周期信号来源于斜率振幅调制周期s3-s6。它通过调控早二叠世地球中高纬度水循环过程影响有机碳埋藏,而沉积盆地中的阈值响应效应将高频的斜率周期中的较低频17万年振幅调制周期放大,并出现在地质记录中。[Objective]Milankovitch cycles affect the Earth's climate system and organic carbon burial by regulating the Earth's astronomical orbital parameters.In addition to the conventional astronomical cycles that regulate the cli-mate system through linear processes,there are"unconventional"astronomical cycles that regulate the climate sys-tem through a series of"non-linear"positive or negative feedback processes,such as the 170 kyr obliquity amplitude modulation(AM)cycle.Previous studies have demonstrated the modulating effect of the 170 kyr cycle on organic car-bon burial in the middle to high latitudes of the Earth during the Mesozoic-Cenozoic.However,owing to the lack of accurate astronomical solutions and high-resolution geological records,the 170 kyr cycle has rarely been reported in the Paleozoic.[Methods]In this study,the total organic carbon content and natural gamma logging data of the Early Permian Lucaogou Formation in the Junggar Basin were analyzed with cyclostratigraphy,which concluded that the Lucaogou Formation has preserved short eccentricity,obliquity,and precession cycles.[Results and Discussions]The astronomical tuning results based on the short eccentricity cycle show that the deposition duration of the Lucao-gou Formation is~2.8 Myr,and the sedimentary rate is estimated at 9.1 cm/kyr.In addition to conventional astro-nomical cycles,the 170 kyr cycle was found in detrended data series and their obliquity AM series,which is the first systematic exploration of the 170 kyr cycle in a Paleozoic terrestrial basin[.Conclusions]Based on the strong obliqui-ty signals,this 170 kyr cycle likely originates from the s3-s6 obliquity AM cycle.It can affect organic carbon burial by modulating water circulation processes in the middle to high latitudes of the earth during the Early Permian.Further-more,the threshold response effect in sedimentary basins amplifies the 170 kyr AM cycle in the obliquity cycle and appears in the geological record.

关 键 词：旋回地层学 17万年天文周期 二叠纪 准噶尔盆地 芦草沟组 

分 类 号：P53[天文地球—古生物学与地层学]