Late Jurassic to early Cretaceous magnetostratigraphy of scientific drilling core LK-1 in the Lingshan Island of Riqingwei Basin,eastern China  

作　　者：Yanjun CHENG Zhiping WU Xiaoyu LIU Yaoqi ZHOU Yining DAI Tongjie ZHANG Tengfei ZHOU 

机构地区：[1]College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,China [2]School of Geosciences,China University of Petroleum(East China),Qingdao 266580,China

出　　处：《Science China Earth Sciences》2022年第4期742-758,共17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.42002030,42072169);National Science and Technology Major Project(Grant No.2016ZX05024-002-001);the Key R&D Plan of Shandong Province(Grant No.2017CXGC1608);the Natural Science Foundation of Shandong Province(Grant No.ZR201910280267)。

摘　　要：The Sulu orogenic belt is an uplift zone that was formed in the Late Triassic.Several Jurassic to Cretaceous sedimentary successions have been recognized within the Sulu orogenic belt in recent studies,including outcrops that are considered to be related to the newly discovered Riqingwei Basin.This basin has been the focus of extensive study due to its continuous Cretaceous rock sequence,geological location and petroleum resource potential.However,the lack of a consolidated chronology for the strata has precluded a better understanding of stratigraphy,tectonic evolution and resource potential of the Riqingwei Basin.Here,we present the results of a new magnetostratigraphic study of the continental scientific drilling borehole LK-1,which is located on Lingshan Island,offshore Shandong province,eastern China.The goals of this study are to(1)refine the Late Jurassic to Early Cretaceous chronostratigraphic framework of the Riqingwei Basin,and(2)investigate the location of the J/K boundary in the Borehole Core LK-1.The observed patterns of the paleomagnetic polarity zone in the LK-1 borehole correlate well with the geomagnetic polarity time scale(GPTS),and the continuous magnetostratigraphy profile defined in this core indicates an age ranging from 146.5 to 125.8 Ma for the samples interval.The sediment accumulation rates(SAR)of LK-1 show one period of high SAR(~10.5 cm kyr^(-1))at 135.3–130.6 Ma and two periods of low SAR(~4.8 and~2.2 cm kyr^(-1))at145.7–135.3 and 130.6–125.8 Ma,respectively.In addition,the magnetostratigraphic results suggest that the Jurassic-Cretaceous(J/K)boundary of the LK-1 is located within the magnetozone N21.2 n(~1254 m).This comprehensive geochronologic framework provides a good correlation of the marine Upper Jurassic to Lower Cretaceous strata in the Riqingwei Basin to other marine strata and continental sequences,in addition to providing a foundation for the study of the structural evolution of eastern China.

关 键 词：MAGNETOSTRATIGRAPHY Continental Scientific Drilling borehole LK-1 J/K boundary Late Jurassic to Early Cretaceous Riqingwei Basin 

分 类 号：P618.13[天文地球—矿床学]