格尔木——额济纳旗地学断面地体构造的古地磁学研究

给出了格尔木－额济纳旗地学断面及其邻区的２３个古地磁新数据，为该区地体构造的划分提供了古地磁证据。提出北山北部地体属于哈萨克斯坦板块的东延部分，探讨了该板块晚古生代的逆时针旋转运动，分析了塔里木板块的演化特点，该板块大约于泥盆纪通过顺时针旋转运动与哈萨克斯坦板块对接拼合，应用多个参考点古纬度资料研究板块运行特征的方法，分析了断面域及其区地体构造的演化过程。研究发现了北祁连地体的古生代南向位移事件，     

红河断裂带白垩纪古地磁及青藏高原地质构造演化

红河断裂带两侧古地磁结果表明,羌塘地体与扬子地台至少从早白垩世以来已连接为一个整体。青藏高原是由四个发育历史不同的地体组成的大地构造复合体,在晚古生代它们分别是劳亚古陆、华夏复合古陆和冈瓦纳古陆的组成部分。拉萨地体与羌塘地体碰撞拼合形成欧亚板块构造格局。喜玛拉雅地体、印度板块与欧亚板块碰撞拼合、推挤,使青藏高原隆起,并使欧亚板块的块体沿已存在的断层产生左行走滑,这种作用至今仍在继续     

中国满洲里──绥芬河地学断面地球物理综合研究

叙述满洲里－绥芬河地学断面的地球物理成果．断面全长１３００ｋｍ，穿越了中国东北的大兴安岭岩浆岩带和张广才岭岩浆岩带，松辽盆地和海拉尔盆地，以及郯庐断裂北延部分的敦化－密山断裂、佳木斯－伊通断裂．结合地质资料，解释了断面多种地球物理方法的资料，包括重力、磁力、大地电磁（ＭＴ）、地震（广角地震测深、垂直反射地震与天然地震）、地热、古地磁以及综合解释，给出了断面岩石层构造的地球物理解释模型．讨论了松辽盆地基底的性质、莫霍界面的性质、大兴安岭重力梯级带的特征与成因，以及断面域地块拼合过程．研究结果认为，东北亚大地是一个拼合的增生大陆，是世界上一种新型的小地块碰撞拼合时受大洋板块俯冲的应力场作用形成的盆、山相间结构．     

中国三大地块的碰撞拼合与古欧亚大陆的重建

根据最新取得的华北地块的古地磁数据,并与目前收集到的按一定判据经过筛选的华南地块、塔里木地块、蒙古褶皱带与中亚褶皱带、西伯利亚板块以及稳定欧亚大陆的数据对比分析,对中国三大地块--华北、华南、塔里木地块的碰撞、拼合及其与北邻的西伯利亚板块的构造关系,进行了初步的讨论,并尝试作了古欧亚大陆的重建.     

华南和华北陆块显生宙的古地磁及构造演化

本文采用给每个岩石单元的古地磁极以单位权的方法,对目前收集到的、并按一定可靠性判据选择出来的华南和华北陆块的古地磁数据,进行了统计分析,绘制了它们的显生宙视极移曲线。进而根据古地磁结果,分析了两大陆块显生宙的构造演化,着重探讨了它们的碰撞时限和拼合过程。     

从沉积特征研究格尔木－额济纳旗地学断面走廊域地体的构造演化史

将格尔木－额济纳旗地学断面走廊域及其邻区划分为１４个地体，分属扬子－华南、华北－柴达木、塔里木和哈萨克斯坦－准噶尔４个板块，其间为规模不等的洋盆所分隔．从中元古代以来，上述板块经历了开裂到碰撞、拼合的复杂过程．主要的事件包括：早古生代时期祁连小洋盆的闭合、柴达木－祁连重新和华北拼合；石板井－小黄山洋盆闭合，塔里木和哈萨克斯坦－准噶尔板块拼合；晚古生代时期阿尔金洋盆和古亚洲洋闭合，柴达木－华北、塔里木－准噶尔和西伯利亚拼合成一个完整陆块；中新生代时期，除了受南侧特提斯洋盆活动及陆块碰撞的影响以外，一系列陆相盆地沉积、陆内构造变动及青藏高原隆升成为该区构造演化中的主要事件．     

腾冲火山区域构造演化过程

根据腾冲火山区在区域上的构造亲缘关系、构造时空演化关系 ,并借助古地磁研究成果而得出的腾冲及邻区主要板块拼合关系 ,研究该区地壳构造演化过程     

中国新生代古地磁数据表

在地质历史时期曾一度彼此分离的中朝扬子、塔里木地块,于古生代末—中生代早期碰撞、拼合,并于中生代末焊合,与欧亚板块形成统一的整体,从而结束了它们之间大幅度相对运动的历史。然而板块(包括地块)内部由断裂围限的次一级块体在构造应力作用下彼此之间也会产生相对运动。这种运动表现为块体绕水平轴的掀斜和绕垂直轴的转动。通常,在野外可直接观测块体的掀斜量,而转动量则不能直接获得。正是由于古地磁的测试能够定性或半定量地测得地块的转动量,从而为研究新构造提供基础资料     

腾冲火山地热区的构造演化与火山喷发

讨论了腾冲地区在Ｄ－Ｅ２时期的板块拼合演化过程及其大地构造单元位置，用以说明腾冲火山地热区的现今区域构造条件，讨论了火山喷发时期与板块碰撞时代的关系。     

显生宙中国大地构造演化的古地磁研究

根据古地磁数据可靠性的试用判据，对华北、杨子、塔里木中国三大稳定地块显生宙的构造古地磁数据做了初步检验，考虑古极点的密集区，选用２２９个古极点以“世”或“纪”为单位进行统计，获得三大稳定地块显生宙综合古地磁视极移曲线。以此为基本依据，结合地质构造、古生物和全球古地理重建图的综合分析，初步探讨了三大稳定地块运动演化的大致轮廓，华北、杨子、塔里木地块碰撞、拼接时限和方式以及华北地块与西伯利亚板块运动演化的关系     

Mianlüe tectonic zone and Mianlüe suture zone on southern margin of Qinling-Dabie orogenic belt

The Mianlue tectonic zone (Mianlue zone), an ancient suture zone in addition to theShangdan suture in the Qinling-Dabie orogenic belt, marks an important tectonic division geo-logically separating north from south and connecting east with west in China continent. To de-termine present structural geometry and kinematics in the Mianlue tectonic zone and to recon-struct the formation and evolution history involving plate subduction and collision in theQinling-Dabie orogenic belt, through a multidisciplinary study, are significant for exploring themountain-building orogenesis of the central orogenic system and the entire process of the majorChinese continental amalgamation during the Indosinian.     

Mianle tectonic zone and Mianle suture zone on southern margin of Qinling-Dabie orogenic belt

The Mianle tectonic zone, defined as a series of fault zones consisting mainly of south-verging thrusts and nappes, represents the south boundary of the Qinling-Dabie orogenic belt. The north side of the eastern end of the Mianle tectonic zone adjoins the exposure of the Dabieshan UHP rocks. Further to east, the zone was offset by the Tanlu faults and moved to eastern Shandong Province. While to its west, across the Qinghai-Tibetan Plateau, the zone was dislocated by the Altun fault, and…     

Three evolutionary stages of the collision orogenic deformation in the Middle Yangtze Region

A discussion of collision orogenic deformation has been made for the Middle Yangtze Region. Based on its deformation assemblage orders, three developing stages are classified successively as compression thrust uplift, strike-slip escape rheology and tension extension inversion. The collision orogenesis of the studied region has been divided into three developing periods of initial, chief and late orogeny. Based on the data from Wugong Mts., Jiuling Mts. and Xuefeng Mts., for each stage, its variation of stress and strain axes, the conversion of joint fractures and their relative tectonic evolution are described, models are plotted and corresponding explanations are made for the rock chronology dating value in the same tectonic period.     

鄂尔多斯盆地晚古生代以来古地磁研究

在鄂尔多斯盆地的韩城、铜川等7条剖面144个采样点上,采集了下二叠统至下白垩统的样品约1500个.分别在中国、英国、法国的4个古地磁实验室中进行测试和实验研究.样品均经系统热退磁或交变退磁处理.数据经主向量分析、部分线性谱分析,以分离剩磁成分和选取特征剩磁方向.全部特征剩磁方向通过了倒转检验,晚二叠世和早、中三叠世的结果还通过了广义褶皱检验.并做了大量磁化率、等湿剩磁、薄片岩矿鉴定和少量居里温度测定的实验研究. 所得数据以世（统）为单位计算了古地磁极位置和采样地区古纬度,绘制了鄂尔多斯盆地晚古生代以来视极移曲线和地块古方位变化图,提出了华北地块运动模式,并通过与现有的华南地块资料的综合对比分析,提出华北地块与华南地块的碰撞在东部始于晚三叠世之前,全部拼合完成于中侏罗世末.     

An optimised method for calculating the O+-O collision parameter from aeronomical measurements

A study has been made of the interaction between the thermosphere and the ionosphere at high latitudes, with particular regard to the value of the O⁺-O collision parameter. The European incoherent scatter radar (EISCAT) was used to make tristatic measurements of plasma parameters at F-region altitudes while simultaneous measurements of the neutral wind were made by a Fabry-Perot interferometer (FPI). The radar data were used to derive the meridional neutral winds in a way similar to that used by previous authors. The accuracy of this technique at high latitudes is reduced by the dynamic nature of the auroral ionosphere and the presence of significant vertical winds. The derived winds were compared with the meridional winds measured by the FPI. For each night, the value of the O⁺-O collision parameter which produced the best agreement between the two data sets was found. The precision of the collision frequency found in this way depends on the accuracy of the data. The statistical method was critically examined in an attempt to account for the variability in the data sets. This study revealed that systematic errors in the data, if unaccounted for by the analysis, have a tendency to increase the value of the derived collision frequency. Previous analyses did not weight each data set in order to account for the quality of the data; an improved method of analysis is suggested.     

Investigation of Crustal Thickness in Eastern Anatolia Using Gravity,Magnetic and Topographic Data

The tectonic regime of Eastern Anatolia is determined by the Arabia-Eurasia continent-continent collision. Several dynamic models have been proposed to characterize the collision zone and its geodynamic structure. In this study, change in crustal thickness has been investigated using gravity, magnetic and topographic data of the region. In the first stage, two-dimensional low-pass filter and upward analytical continuation techniques were applied to the Bouguer gravity data of the region to investigate the behavior of the regional gravity anomalies. Next the moving window power spectrum method was used, and changes in the probable structural depths from 38 to 52 km were determined. The changes in crustal thickness where free air gravity and magnetic data have inversely correlated and the type of the anomaly resources were investigated applying the Euler deconvolution method to Bouguer gravity data. The obtained depth values are consistent with the results obtained using the power spectrum method. It was determined that the types of anomaly resources are different in the west and east of the 40° E longitude. Finally, using the obtained findings from this study and seismic velocity models proposed for this region by previous studies, a probable two-dimensional crust model was constituted.     

苏北-胶南构造混杂岩带的地质特征和岩性地层柱

本文简要介绍了产于华北板块与扬子板块碰撞带范围内的苏北-胶南构造混杂岩带的地质构造背景,并系统地研究滑移介质、中-浅源和深源构造块的基本特征。在深源构造岩块的研究基础上建立了壳幔过渡带至上地幔段的岩性地层柱,对上地幔可能存在的地质作用类型进行了探讨     

The Lhasa Terrane: Record of a microcontinent and its histories of drift and growth

The Lhasa Terrane in southern Tibet has long been accepted as the last geological block accreted to Eurasia before its collision with the northward drifting Indian continent in the Cenozoic, but its lithospheric architecture, drift and growth histories and the nature of its northern suture with Eurasia via the Qiangtang Terrane remain enigmatic. Using zircon in situ U–Pb and Lu–Hf isotopic and bulk-rock geochemical data of Mesozoic–Early Tertiary magmatic rocks sampled along four north–south traverses across the Lhasa Terrane, we show that the Lhasa Terrane has ancient basement rocks of Proterozoic and Archean ages (up to 2870 Ma) in its centre with younger and juvenile crust (Phanerozoic) accreted towards its both northern and southern edges. This finding proves that the central Lhasa subterrane was once a microcontinent. This continent has survived from its long journey across the Paleo-Tethyan Ocean basins and has grown at the edges through magmatism resulting from oceanic lithosphere subduction towards beneath it during its journey and subsequent collisions with the Qiangtang Terrane to the north and with the Indian continent to the south. Zircon Hf isotope data indicate significant mantle source contributions to the generation of these granitoid rocks (e.g., ~ 50–90%, 0–70%, and 30–100% to the Mesozoic magmatism in the southern, central, and northern Lhasa subterranes, respectively). We suggest that much of the Mesozoic magmatism in the Lhasa Terrane may be associated with the southward Bangong–Nujiang Tethyan seafloor subduction beneath the Lhasa Terrane, which likely began in the Middle Permian (or earlier) and ceased in the late Early Cretaceous, and that the significant changes of zircon ε_Hf(t) at ~ 113 and ~ 52 Ma record tectonomagmatic activities as a result of slab break-off and related mantle melting events following the Qiangtang–Lhasa amalgamation and India–Lhasa amalgamation, respectively. These results manifest the efficacy of zircons as a chronometer (U–Pb dating) and a geochemical tracer (Hf isotopes) in understanding the origin and histories of lithospheric plates and in revealing the tectonic evolution of old orogenies in the context of plate tectonics.