Magnetostratigraphy of the middle-upper Jurassic sedimentary sequences at Yanshiping, Qiangtang Basin, China
Magnetostratigraphy of the middle-upper Jurassic sedimentary sequences at Yanshiping, Qiangtang Basin, China
复制标题
羌塘盆地雁石坪中上侏罗统沉积层序的磁性地层学
DOI：
10.1093/gji/ggw199
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发表时间：
2016-09
影响因子：
2.8
通讯作者：
Xifang Liu
中科院分区：
文献类型：
--
作者：
Xiaomin Fang;Jing Bao;Jinbo Zan;Xifang Liu
侏罗纪青藏高原地区发生了拉萨地体与羌塘地体碰撞、中特提斯洋闭合、新特提斯洋开启和大季风停止等一系列重大地质事件。青藏高原中部羌塘盆地中一套厚约3000 m的侏罗系沉积层序--雁石坪群（YSP）记录了这些地质事件。然而，令人惊讶的是，该序列的年表受到的约束很差。本文对羌塘盆地东部YSP剖面YSP群中上部约1060 m厚的夏里组和索瓦组进行了详细的古地磁分析。在40-140、640-800和940-1040 m的地层间距上划分出三个双壳类带，给出了夏里组下段的年代为Duponian-Calovian，下苏瓦组为卡洛夫-牛津时代。上苏瓦组的时代为牛津-基默里纪。在剖面上共采集到544个定向古地磁样品。通过结合热退磁和交变场退磁，对于大多数样品，分离出清晰的特征剩磁（ChRM）方向。强大的ChRM方向通过折叠和反转测试，这支持的ChRM的主要性质，并产生在76.8A度N/297.2A度E（dp = 2.2A度，dm = 3.7A度）的古极点。共成功记录了27个正常和26个反极性区。结合化石年龄的限制，结果表明，该部分是合理的组成的一个Callovian-Early Kimmeridgian年龄沉积序列。
A series of important geological events occurred in the Tibetan Plateau area during the Jurassic, such as the collision of the Lhasa and Qiangtang Terranes, the closure of the Meso-Tethyan Ocean, the opening of the Neo-Tethyan Ocean and the cessation of the mega-monsoon. The similar to 3000 m thick Jurassic sedimentary sequence in the Qiangtang Basin on the central Tibetan Plateau, which is called the Yanshiping (YSP) Group, recorded these geological events. However, the chronology of the sequence is surprisingly poorly constrained. Here, we perform a detailed palaeomagnetic analysis on the similar to 1060 m thick middle and upper portions of the YSP Group (the Xiali and Suowa Formations) in the YSP section of the eastern Qiangtang Basin. Three bivalve zones at stratigraphic intervals of similar to 40-140, 640-800 and 940-1040 m are identified, which yield a Bathonian-Callovian age for the Lower Xiali Fm., a Callovian-Oxfordian age for the Lower Suowa Fm. and an Oxfordian-Kimmeridgian age for the Upper Suowa Fm. A total of 544 oriented palaeomagnetic samples were collected from the section. By combining thermal and alternating field demagnetizations, clear characteristic remanent magnetization (ChRM) directions are isolated for most of the samples. The robust ChRM directions pass fold and reversals tests, which support the primary nature of the ChRMs and yield a palaeopole at 76.8A degrees N/297.2A degrees E (dp = 2.2A degrees, dm = 3.7A degrees). A total of 27 normal and 26 reversed polarity zones were successfully recorded in the section. Combined with fossil age constraints, results suggest that the section is plausibly composed of a Callovian-Early Kimmeridgian age sedimentary sequence.
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影响因子：
2.9
作者：
D. Handschumacher;W. Sager;T. Hilde;D. R. Bracey
通讯作者：
D. Handschumacher;W. Sager;T. Hilde;D. R. Bracey
影响因子：
2.1
作者：
J. Sandoval;J. M. Tavera
通讯作者：
J. Sandoval;J. M. Tavera
影响因子：
4.9
作者：
G. Muttoni;D. Kent;P. Olsen;P. Stefano;W. Lowrie;S. Bernasconi;F. Hernández
通讯作者：
G. Muttoni;D. Kent;P. Olsen;P. Stefano;W. Lowrie;S. Bernasconi;F. Hernández
影响因子：
5.8
作者：
M. Tivey;W. Sager;Sang‐Mook Lee;M. Tominaga
通讯作者：
M. Tivey;W. Sager;Sang‐Mook Lee;M. Tominaga
DOI：
10.1016/0031-0182(90)90023-z
发表时间：
1990-08
期刊：
Palaeogeography, Palaeoclimatology, Palaeoecology
影响因子：
--
作者：
J. Channell;F. Massari;A. Benetti;N. Pezzoni
通讯作者：
J. Channell;F. Massari;A. Benetti;N. Pezzoni