Intensive peatland wildfires during the Aptian-Albian oceanic anoxic event 1b:Evidence from borehole SK-2 in the Songliao Basin,NE China  

作　　者：Zhi-Hui Zhang Da-Wei Lü Tian-Tian Wang Dong-Zhao An Hai-Yan Liu Dong-Dong Wang Cheng-Shan Wang 

机构地区：[1]Shandong Provincial Key Laboratory of Depositional Mineralization and Sedimentary Minerals,College of Earth Sciences and Engineering,Shandong University of Science and Technology,Qingdao 266590,Shandong Province,China [2]Institute of Earth Sciences,China University of Geosciences,Beijing 100083,China [3]School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China [4]Chinese Academy of Geological Sciences,Beijing 100037,China

出　　处：《Journal of Palaeogeography》2022年第3期448-467,共20页古地理学报（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Grant Nos.42102127,42172117,41772096);the Natural Science Foundation of Shandong Province(Grant No.ZR2021QD087);the Chinese Postdoctoral Science Foundation(Grant No.2021M702019);the SDUST Research Fund,Shandong University of Science and Technology(Grant No.2018TDJH101)。

摘　　要：The Cretaceous has been considered a“high-fire”world accompanied by widespread by-products of combustion in the rock record.The mid-Cretaceous oceanic anoxic event 1b(OAE1b)is marked by one of the major perturbations in the global carbon cycle characterized by deposition of organic-rich sediments in both marine and terrestrial settings.However,our understanding is still limited on changes in wildfire activity during OAE1b period.Here,we carried out a comprehensive analysis,including organic carbon isotope(δ^(13)C_(org)),total organic carbon(TOC),coal petrology,trace elements,and pyrolytic polycyclic aromatic hydrocarbons(pyroPAHs),of coal seams of the middle Aptian to early Albian Shahezi Formation from borehole SK-2 in Songliao Basin,Northeast China.Two negativeδ^(13)C_(org) excursions in the Shahezi Formation can be corresponded with the 113/Jacob and Kilian sub-events of OAE1b.Moreover,the intensive peatland wildfires have been identified during the sub-event periods of OAE1b based on the co-occurrence of high abundance of charcoal and pyroPAHs at that time.In addition,Sr/Ba,Sr/Cu and Sr/Rb ratios demonstrate that enhanced peatland wildfires were controlled by dryer climate conditions owing to episodic northward migration of arid zones in East Asia related with rising global temperature during the sub-events of OAE1b.The climate-driven extensive wildfire activity in the mid-latitude terrestrial ecosystems can be a contributing factor for OAE1b through the increased flux of nutrients fuelling primary producers in the lake and marine environments and leading to more speculative anoxia to allow the deposition of organic-rich sediments.Our results provide essential understanding of the importance of wildfires in driving mechanism of oceanic anoxic events(OAEs)in Earth's history.

关 键 词：Lower Cretaceous OAEs PEATLAND Wildfire COALS 

分 类 号：P618.13[天文地球—矿床学]