Kanfenggou UHP Metamorphic Fragment in Eastern Qinling Orogen and Its Relationship to Dabie-Sulu UHP and HP Metamorphic Belts, Central China

In the Central Orogenic Belt, China, two UHP metamorphic belts are discriminated mainly based on a detailed structural analysis of the Kanfenggou UHP metamorphic fragment exposed in the eastern Qinling orogen, and together with previous regional structural, petrological and geochronological data at the scale of the orogenic domain. The first one corresponds to the South Altun-North QaidamNorth Qinling UHP metarnorphic belt. The other is the Dabie-Sulu UHP and HP metamorphic belts. The two UHP metamorphic belts are separated by a series of tectonic slices composed by the Qiniing rock group, Danfeng rock group and Liuling or Foziling rock group etc. respectively, and are different in age of the peak UHP metamorphism and geodynamic implications for continental deep subduction and collision. Regional field and petrological relationships suggest that the Kanfenggou UHP metamorphic fragment that contains a large volume of the coesite- and microdiamond-bearing eclogite lenses is compatible with the structures recognized in the South Altun and North Qaidam UHP metamorphic fragments exposed in the western part of China, thereby forming a large UHP metamorphic belt up to 1000 km long along the orogen strike. This UHP metamorphic belt represents an intercontinental deep subduction and collision belt between the Yangtze and Sino-Korean cratons, occurred during the Paleozoic. On the other hand, the well-constrained Dabie-Sulu UHP and HP metamorphic belts occurred mainly during Triassic time (250-220 Ma), and were produced by the intracontinental deep subduction and collision within the Yangtze craton. The Kanfenggou UHP metamorphic fragment does not appear to link with the DabieSulu UHP and HP metamorphic belts along the orogen. There is no reason to assume the two UHP metamorphic belts as a single giant deep subduction and collision zone in the Central Orogenic Belt situated between the Yangtze and Sino-Korean cratons. Therefore, any dynamic model for the orogen must ac-count for the development of UHP metarnorphic rocks belonging to the separate two tectonic belts of different age and tectono-metamorphic history.     

基于H.323协议的独立IP可视电话的设计与实现

论述了独立IP可视电话实现的关键技术，介绍了H．323协议的相关内容，并在H．323协议框架的基础上提出了一种可行的独立IP可视电话的设计和实现方案。     

Geochemical and Sm–Nd isotopic characteristics of metabasites from central Hainan Island, South China and their tectonic significance

Abstract   Major and trace elements and Sm–Nd isotopic data are presented for metabasites that are present as lenses within Paleozoic metasediments in the Chenxing and Bangxi regions, central Hainan Island, Southeast (SE) China. Most metabasites are metamorphosed cumulated gabbroic rocks tholeiitic in nature, and characterized by varying degrees of depletion in Th, Nb, Ta and light rare earth elements (LREE). Moreover, they show high positive ∈Nd(T) values of approximately +7, similar to those of mid-ocean ridge basalts (MORB). A Sm–Nd isochron age of 333 ± 12 Ma obtained for the metabasites is interpreted as their crystallization age. The combined geochemical and Sm–Nd isotopic data suggest that the metabasites were generated by dynamic partial melting from a MORB-like mantle source in an oceanic regime. These rocks probably represent remnants of fragmented oceanic crust of the eastern part of Paleo-Tethys. They were obducted onto the continental crust as part of the 'Shilu Mélange' in earliest Mesozoic time when southern Hainan (part of the Indochina block) collided with northern Hainan (part of South China). Alternatively, they could be formed in a volcanic rifted passive margin at the sea-floor spreading stage as part of MORB-like seaward-dipping reflector break-up packages.     

极低级变质作用和极低级变质带综述

极低级变质作用是指变质作用最低级的部分，包括成岩作用和浅层变质作用，其变质温度范围大体介于１５０－３７０℃之间。本文简要地对极低级变质作用和极低级变质带的特征和研究领域进行综述，可以看出，通过极低级变质作用和极低级变质带的研究，能够提供造山带、沉积盆地演化及板劈理发育等有关地球动力学过程和流变状态信息；强调指出进一步研究极低级变质作用和极低级变质带的必要性。     

豫西东秦岭造山带低压变质带的变质变形和变质反应

豫西西峡北部低压变质带受到４次变形改造。低压变质作用主要发生在Ｄ１和Ｄ２变形间期，形成黑云母－红柱石、石榴石－红柱石、十字石－红柱石和堇青石－红柱石４个递增变质带。由矿物变质反应识别出堇青石－红柱石带ｐ－Ｔ趋势具有减压增温特点，这一演化特征可能反映变质作用具有地壳拉张的地球动力学特点。     

云开隆起区钾长球斑片麻状黑云母花岗岩锆石特征研究——形貌、成分以及U-Pb同位素年龄

云开隆起区核部广泛出露的钾长球斑片麻状黑云母花岗岩中存在形貌、成分不同的3类锆石,这些锆石的单颗粒U—Pb同位素年龄明显不同,说明此类陆壳改造型花岗岩源岩成因复杂,源岩时代老于1364Ma,岩体形成时代为463～508Ma。     

云开隆起低压麻粒岩相变质作用时代的重要发现

首次报道云开隆起低压麻粒岩９５０Ｍａ左右的变质作用年龄，结合麻粒岩的岩相学以及区域地质特征，指出晋宁期云开地区处于拉张的构造环境。     

东昆仑黑海地区沙松乌拉组变质碎屑岩的地球化学特征及其对物质来源的约束

沙松乌拉组是整个东昆仑地区早古生代最早的海相沉积,是原特提斯洋盆打开时的沉积记录。对沙松乌拉组的物质来源进行研究,可以为恢复和反演东昆仑地区早古生代构造格局提供依据。本文在野外地质调查的基础上,对沙松乌拉组的岩石地球化学特征进行了研究。通过系列判别图解,得到沙松乌拉组的岩石类型为杂砂岩、岩屑砂岩,源岩主要为长英质及部分古老沉积组分;得到物源区大地构造环境主要为大陆岛弧和活动大陆边缘,少量物源来自被动大陆边缘。分析前期通过碎屑锆石法得到的小庙群、万宝沟群、晋宁期岩浆岩及白沙河组物源区的形成环境及岩石性质,与地球化学判别结果较为吻合。     

横断面测图比例尺及断面间距对挖填工程量的精度影响

横断面测图比例尺及断面间距的选择，直接影响到挖填工程量的计算精度，本文通过对方量精度估算分析，提出了供设计人员和测绘人员参考的测量方案。