As a part of INDEPTH 3/GEODEPTH geological surface investigations were carried out during two field campaigns in 1998 and 1999. The working area covers a roughly N\|S (30～36°N) tren ding, 200km wide belt through...As a part of INDEPTH 3/GEODEPTH geological surface investigations were carried out during two field campaigns in 1998 and 1999. The working area covers a roughly N\|S (30～36°N) tren ding, 200km wide belt through the Lhasa Terrane and Qiangtang Terrane at a longitude of 88～90°E. Field geology was focused on geological mapping, structural measurements, and extensive sampling for the purpose of fission track geochronology. Additionally a total number of 742 orientated palaeomagnetic samples were drilled at 73 sites. Most of the samples were taken in fine\|grained sediments of Cretaceous, Eocene, and Neogene age. Five sites were drilled in acid to intermediate volcanics.A first sequence of measurements has been applied on a set of specimen. Most of the chosen formations (>80%) have acquired stable remanences which are carried by hematite and magnetite. As an example for the characteristic demagnetising behaviour of fine\|grained probable Cretaceous sandstones see Fig.1a. The unblocking temperature of 650℃ allows to identify hematite as remanence carrier.. Although single sites show well\|defined mean directions (e.g. site 76B: α 95 =3 8; k =185 8) the distribution among several site means of one formation could scatter (Fig.1b). It has to be checked carefully if rotations of single crustal elements are responsible for this effect. There is evidence to assume the detected characteristic remanences to be primary—further analysis including fold tests will be performed after the data set has increased.展开更多
随着藏中丰富的矿产资源逐步进入深度开发阶段,农牧民和政府对矿企的发展制约越来越强,F and H-G-C系统协调矛盾凸显。文章通过建立藏中矿区F and H-G-C系统协调评价体系和评价指标,并结合实证数据,分析研究藏中矿区F and H-G-C系统存...随着藏中丰富的矿产资源逐步进入深度开发阶段,农牧民和政府对矿企的发展制约越来越强,F and H-G-C系统协调矛盾凸显。文章通过建立藏中矿区F and H-G-C系统协调评价体系和评价指标,并结合实证数据,分析研究藏中矿区F and H-G-C系统存在的主要问题,提出促进藏中矿区F and H-G-C系统协调发展的建议。展开更多
文摘As a part of INDEPTH 3/GEODEPTH geological surface investigations were carried out during two field campaigns in 1998 and 1999. The working area covers a roughly N\|S (30～36°N) tren ding, 200km wide belt through the Lhasa Terrane and Qiangtang Terrane at a longitude of 88～90°E. Field geology was focused on geological mapping, structural measurements, and extensive sampling for the purpose of fission track geochronology. Additionally a total number of 742 orientated palaeomagnetic samples were drilled at 73 sites. Most of the samples were taken in fine\|grained sediments of Cretaceous, Eocene, and Neogene age. Five sites were drilled in acid to intermediate volcanics.A first sequence of measurements has been applied on a set of specimen. Most of the chosen formations (>80%) have acquired stable remanences which are carried by hematite and magnetite. As an example for the characteristic demagnetising behaviour of fine\|grained probable Cretaceous sandstones see Fig.1a. The unblocking temperature of 650℃ allows to identify hematite as remanence carrier.. Although single sites show well\|defined mean directions (e.g. site 76B: α 95 =3 8; k =185 8) the distribution among several site means of one formation could scatter (Fig.1b). It has to be checked carefully if rotations of single crustal elements are responsible for this effect. There is evidence to assume the detected characteristic remanences to be primary—further analysis including fold tests will be performed after the data set has increased.
文摘随着藏中丰富的矿产资源逐步进入深度开发阶段,农牧民和政府对矿企的发展制约越来越强,F and H-G-C系统协调矛盾凸显。文章通过建立藏中矿区F and H-G-C系统协调评价体系和评价指标,并结合实证数据,分析研究藏中矿区F and H-G-C系统存在的主要问题,提出促进藏中矿区F and H-G-C系统协调发展的建议。
