地质通报2018，Vol.37Issue(5)：759-775,17.
青藏高原东南缘保山地体上新世地壳旋转变形运动的古地磁学研究及构造意义
Paleomagnetic study of Pliocene lacustrine strata in the Baoshan Basin at the southeastern edge of the Tibetan Plateau
摘要
Abstract
The southeastern part of the Tibetan Plateau has been strongly deformed by the penetration of the Indian Plate since the early Cenozoic.A large clockwise rotation of the Baoshan Terrane was reported through previous paleomagnetic studies.The authors therefore carried out a paleomagnetic study of the Pliocene lacustrine strata in the Baoshan Basin.A total of about 160 samples were treated by thermal demagnetization,and the characteristic remanent magnetism components (ChRMs) were isolated from these samples along the Yangyi section (YYN),southeastern part of Baoshan Basin.Site-mean direction from the YYN is Ds/Is=20.21°/37.1°,Ks=59.7,α95=4.8°,N=16 after tilt correction,which give a paleomagnetic pole at 67.9°N,205.7°E,A95=2.6°.The ChRM directions of the YYN section pass the fold and reversal tests,indicating that it represents the primary remanent magnetization during the formation of sedimentary rocks.The results reveal that the Baoshan Terrane has suffered from a clockwise rotation about 19.2°±6° relative to the paleomagnetic reference pole of East Asia since the Pliocene.Based on a comparison with the magnetostratigraphic results of the drilled core on the east margin of Baoshan basin,the authors hold that the age of the sampled strata of the YYN section is 6±0.2Ma,and a mean rotating rate of the Baoshan basin is about 3.2°±1.0°/Ma.This result is consistent with the large clockwise rotation of the Baoshan basin since the Miocene revealed by Oligocene and Miocene paleomagnetic studies of the Baoshan Terrane and Tengchong Block.关键词
青藏高原东南缘/保山地体/古地磁/上新世/旋转运动Key words
southeastern Tibetan Plateau/Baoshan Terrane/paleomagnetism/Pliocene/rotation分类
天文与地球科学引用本文复制引用
蒲宗文,杨振宇,仝亚博,赵越,王恒..青藏高原东南缘保山地体上新世地壳旋转变形运动的古地磁学研究及构造意义[J].地质通报,2018,37(5):759-775,17.基金项目
国家自然科学基金项目《青藏高原东南缘地块新生代侧向逃逸运动及其对地壳构造变形的控制作用》(批准号:41572183)、《云南地区构造变形的GPS测量和中新世以来古地磁研究》(批准号:41672192),中国地质科学院基本科研业务费项目《青藏高原东南缘及东南缘新生代构造变形的古地磁证据》(编号:YYWF201613)和中国地质调查局项目《长江经济带活动构造与区域地壳稳定性调查》(编号:DD20160268) （批准号:41572183）
