Evaluation of the four potential Cretaceous-Paleogene (K-Pg) boundaries in the Nanxiong Basin based on evidences from volcanic activity and paleoclimatic evolution  

作　　者：Mengting ZHAO Mingming MA Mei HE Yudan QIU Xiuming LIU 

机构地区：[1]School of Geographical Sciences,Fujian Normal University,Fuzhou 350007,China [2]Key Laboratory of Humid Sub-tropical Eco-geographical Process of Ministry of Education,Fujian Normal University',Fuzhou 350007,China [3]Key Laboratory for Subtropical Mountain Ecology,Fujian Normal University,Fuzhou 350007,China [4]Department of Environment and Geography,Macquarie University,Sydney NSW 2109,Australia

出　　处：《Science China Earth Sciences》2021年第4期631-641,共11页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 41602185 and 41772180);the International Geoscience Programme (IGCP 679);the Innovation Research Team Fund of Fujian Normal University (Grant No. IRTL1705)。

摘　　要：Determining the location of the Cretaceous-Paleogene(K-Pg) boundary in terrestrial strata is highly significant for studying the evolution of terrestrial ecosystems at the end of the Cretaceous(especially the extinction of non-avian dinosaurs). At present, research on terrestrial K-Pg boundaries worldwide is concentrated in the middle and high latitudes, such as North America and Northeast China. Although many studies have also been carried out in the Nanxiong Basin, located at low latitudes(which has become the standard for dividing and comparing the continental K-Pg stratigraphy in China), many researchers have proposed four possible boundaries from different perspectives. Therefore, the exact location remains to be determined. In this study, the total mercury(Hg) content, environmental magnetism, geochemistry, and other parameters for the samples collected near the four boundaries were determined and compared with existing records. Results indicated that: 1) The total Hg content significantly increased in the upper part of the Zhenshui Formation and Pingling part of the Shanghu Formation with sharp fluctuations. As per latest dating results of Deccan Traps, the significantly high Hg value was attributed to the Deccan Traps eruption. Boundary 1 was located in the middle of the Hg anomaly interval, which was consistent with the relationship between the global K-Pg boundary and time of volcanic eruption. 2) The reconstructed paleoclimate evolution curve revealed that the red sediments in the basin recorded the late Maastrichtian warming event(66.2 Ma). Regarding the relationship between the four boundaries and this warming event, only boundary 1 was found to be closest to the real K-Pg boundary of the Nanxiong Basin.

关 键 词：Nanxiong Basin K-Pg boundary total Hg content late Maastrichtian warming event 

分 类 号：P534.53[天文地球—古生物学与地层学]