松辽盆地南部上、下白垩统界线研究:以松辽盆地国际大陆科学钻探松科3井为例  

The Upper-Lower Cretaceous boundary in the southern Songliao Basin:A case study of ICDP borehole SK-3

作　　者：高航 王璞珺[1] 高有峰[1,2] 万晓樵[3] 杨光 户景松 吴怀春[5] GAO Hang;WANG Pujun;GAO Youfeng;WAN Xiaoqiao;YANG Guang;HU Jingsong;WU Huaichun(College of Earth Sciences,Jilin University,Changchun 130061,China;Research Center of Paleontology and Stratigraphy,Jilin University,Changchun 130026,China;School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China;Exploration Department,Jilin Oilfield Company,PetroChina,Songyuan 138000,China;School of Ocean Sciences,China University of Geosciences(Beijing),Beijing 100083,China)

机构地区：[1]吉林大学地球科学学院,吉林长春130061 [2]吉林大学古生物学与地层学研究中心,吉林长春130026 [3]中国地质大学(北京)地球科学与资源学院,北京100083 [4]中国石油吉林油田分公司勘探部,吉林松原138000 [5]中国地质大学(北京)海洋学院,北京100083

出　　处：《地学前缘》2023年第3期425-440,共16页Earth Science Frontiers

基　　金：国家重点研发计划项目(2019YFC0605402);国家自然科学基金项目(41790453)。

摘　　要：国际上公认的上、下白垩统界线绝对年龄为100.5 Ma,该界线的“金钉子”位于海相地层中,而陆相层序中有关该地层界线的“金钉子”迄今尚无报道。陆相上、下白垩统界线的研究对于了解白垩纪中期温室条件下陆地上所经历的古地理、古环境、古气候的演化过程具有重要价值。我国东北地区的松辽盆地发育完整的白垩纪陆相地层,可能为陆相的上、下白垩统地层界线的研究提供连续的地质记录。本文基于松辽盆地国际大陆科学钻探松辽盆地南部松科3井全取心资料,通过对岩石类型、岩性序列和沉积相研究,于井深1191.6 m处的泉头组二段上部滨浅湖相沉积序列中发现灰色、灰绿色流纹质岩屑晶屑沉凝灰岩。通过同沉积期岩浆锆石U-Pb测年获得年龄(96.8±2.9)Ma,时代属于塞诺曼中期。结合前人资料得到研究区登娄库组—泉头组沉积速率为90.54~110 m/Ma,由此确定出上、下白垩统界线位于松科3井泉一段中部(井段1526.6~1598.6 m)。本文在考虑测年结果误差的情况下,另外计算出松科3井上、下白垩统界线介于泉二段中部至登四段上部(井段1279.6~1917.6 m)。其他学者基于松辽盆地北部松科1井和松科2井年代学研究结果,推测该界线应位于登娄库组内部。松科3井连续取心结果揭示的登娄库组和泉头组为连续发育的河流相和湖泊相沉积序列。地震反射层位对比结果显示,在整个松辽盆地内普遍发育登娄库组—泉头组的地层和连续沉积记录,因此在松辽盆地其他地区的登娄库组—泉头组地层中也应存在上、下白垩统界线的连续沉积的地质记录。本文为在松辽盆地及邻区探寻上、下白垩统陆相地层界线的全球“金钉子”提供了基础资料和探索方向。The internationally recognized absolute isotopic age of the Upper-Lower Cretaceous stratigraphic boundary is 100.5 Ma,and the Global Boundary Stratotype Section and Points(GSSP)for the boundary is placed in marine strata;however,there have been no reports of GSSP(“golden spikes”)for terrestrial boundaries anywhere in the world.The terrestrial Upper-Lower Cretaceous stratigraphic boundary is of great value in understanding the evolution of paleogeography,paleoenvironment and paleoclimate on land under the greenhouse conditions in the Middle Cretaceous,and the ideal geological records for studying this boundary may be found in the Songliao Basin,northeastern China,where a complete set of Cretaceous continental strata are developed.Here,we investigated the rock types,lithologic sequence and sedimentary facies in the core section of International Continental Scientific Drilling Program(ICDP)borehole SK-3,southern Songliao Basin.Based on the core description,gray and gray-green rhyolitic lithic crystalline tuffite deposit is found in the coastal-shallow lacustrine sedimentary sequences of the upper part of the second member of the Quantou Formation at 1191.6 m depth.The tuffite deposit,according to zircon U-Pb dating of its syndepositional magmatic components,has an zircon age of(96.8±2.9)Ma and belongs to the Middle-Cenomanian period.Combined with previous data,the deposition rate for the Quantou-Denglouku Formations in the study area is 90.54110 m/Ma,and we conclude accordingly that the Upper-Lower Cretaceous stratigraphic boundary is located in the middle of the first member of the Quantou Formation in borehole SK-3(at 1526.61598.6 m depth).Considering analytical errors in the age-dating results,the Upper-Lower Cretaceous stratigraphic boundary in borehole SK-3 is independently calculated to be between the middle of the second member of the Quantou Formation and the upper part of the fourth member of the Denglouku Formation(at 1279.61917.6 m depth).Other researchers have tentatively placed the boundary in the

关 键 词：松辽盆地 国际大陆科学钻探松科3井 上、下白垩统地层界线 陆相地层界线潜在金钉子 白垩系登娄库组—泉头组 

分 类 号：P534.53[天文地球—古生物学与地层学] P539.2[天文地球—地质学]