西藏申扎地区晚古生代地层岩石磁学研究  

Rock Magnetism of the Late Paleozoic in Xainza area of Tibet,West China

作　　者：程鑫[1] 吴汉宁[1] 郭强[1,2] 侯宝宁[1,3] 王宝江[1,2] 康伟伟 梁利平[1,5] 石月[1] 刘钊[1] 闫昭圣[1] 鱼磊[1] 彭喜明[1] 魏娜娜[1] 

机构地区：[1]西北大学大陆动力学国家重点实验室/地质学系,陕西西安710069 [2]陕西延长石油集团研究院,陕西西安710075 [3]胜利石油管理局滨南采油厂,山东滨州256606 [4]中国石油集团测井有限公司青海事业部,甘肃敦煌736202 [5]中国石油长庆油田分公司输油处,陕西西安710018

出　　处：《西北大学学报（自然科学版）》2012年第5期819-826,832,共9页Journal of Northwest University（Natural Science Edition）

基　　金：国家自然科学基金资助项目(41074045;41174055);中国地质调查局国土资源大调查综合研究基金资助项目(1212010610102);陕西省普通高等学校重点学科专项资金(081802);西北大学大陆动力学国家重点实验室自主研究课题(10DZSY008)

摘　　要：目的研究西藏申扎地区晚古生代地层载磁矿物特征,为构造磁学等提供依据。方法运用饱和等温剩磁(SIRM),三轴等温剩磁(SIRM)热退磁,磁化率-温度(χ-T)曲线和NRM热退磁实验等方法进行综合分析。结果中—上二叠统样品中含较多针铁矿、赤铁矿;下二叠统和石炭系样品中以磁铁矿为主;泥盆系样品中富集铁硫化物。结论该套沉积地层中具有不同磁学特征的磁性矿物共生组合,可能导致岩石剩磁获得过程相对复杂;剖面上磁性矿物组合的变化,蕴含着沉积环境演化的信息。Aim The Gandise block located in the northern margin of Gondwana continent. Gandise marine depos its can help to trace evolutionary history of the Paleo-Tethys in northern Gondwana. Late Palcozoic successions, yielding diversified fossils, are Paleozoic strata seen in Zakang well-exposed in the Xainza area, located in the central part of the Gandise block. ~ / of Xamza is known as the best developed in northern Tibet and would provide key insights into the study of Paleozoic tectonic movement and evolution of the Qinghai-Tibet Plateau. This study pro- vides new insights for studying paleomagnetism and magnetostratigraphy in the Xainza area of Tibet, west China. Methods Rock Magnetism experiments, including progressive acquisition of IRM, thermal demagnetization of a three-component IRM, temperature-dependent magnetic susceptibility measurements, and the thermal demagnetiza-tion, were conducted on the Late Paleozoic deposits recovered from the Zakang section. Results The results show that middle and late Permian sediments have high contents of goethite and hematite ; early Permian and Carbonifer- ous sediments are dominated by magnetite; and Devonian sediments are rich in ferromagnetic iron sulfides. Conclu- sion The diversified magnetic mineral paragenesis in a set of sedimentary strata, may lead to the rock IRM acquisition a relatively complex process; magnetic mineral assemblages in the profile also contains information on the e- volution of depositional environments.

关 键 词：青藏高原 冈底斯 申扎 岩石磁学 晚古生代 

分 类 号：P318[天文地球—固体地球物理学]