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.
出处
《西北大学学报（自然科学版）》
CAS
CSCD
北大核心
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)
关键词
青藏高原
冈底斯
申扎
岩石磁学
晚古生代
Qinghai-Tibet Plateu
Gandise
Xainza
Rock Magnetism
Late Paleozoic
