人工多晶橄榄石样品孔隙压缩高温高压实验研究

人工制备多晶橄榄石样品的高孔隙度是实验关注的问题之一。本文着重研究在给定温度条件下人工多晶橄榄石样品高温高压孔隙压缩问题。文中给出了含水的湿样品和干燥样品孔隙度与实验压力的关系曲线,并提出了衡量样品压实程度的压实系数Ｖｏ／Ｖ的概念。     

土在高压力段的压缩性参数外推方法探讨

根据土高压固结试验的压缩曲线几何特征,提出了基于一定较高压力水平的固结试验结果外推更大压力段的压缩性参数和压缩曲线的方法。实际验证结果表明,该方法简便易行,且精确度较高。     

高密度电法勘探技术及其应用

简述了高密度电法勘探技术的基本原理。从电极排列、数据预处理及反演处理方法等方面介绍了该技术在应用中应注意的关键技术问题及其处理方法,并通过在长-邵高速公路勘察的应用实例,来说明高密度电法勘探技术在岩溶洞穴、地质灾害等探测领域具有较好的探测效果。     

新疆北部的两类埃达克岩

新疆北部有两类埃达克岩，一是俯冲型，形成于早、中泥盆世-早石炭世晚期（≥320Ma），包括了埃达克岩、富Nb玄武岩、高（富）Mg安山岩。第二类埃达克岩是底侵型，形成于中晚二叠世（≤280Ma）。第一类埃达克岩分布于西天山的阿拉套山、博罗科努山，中天山的骆驼沟和巴仑台，东天山的土屋-延东，阿尔泰山陆缘南富蕴-青河南，准噶尔盆地中部陆梁，克拉玛依等地。在阿尔泰陆缘南，苦橄岩与埃达克岩、富Nb玄武岩和高（富）Mg安山岩密切组合。第二类埃达克岩分布于西天山的阿吾拉勒山和东天山的三岔口，未发现富Nb玄武岩和高（富）Mg安山岩组合。俯冲型埃达克岩、富Nb玄武岩和高（富）Mg安山岩的高Sr低Y、Yb、富Eu及高εNd（t）（＋1．5～＋10．0），低（^87Sr／^86Sr）；（〈0．7070）的同位素组成，均一致表明其源区物质为洋壳板片，部分为地幔楔、弧前棱柱，产于岛弧环境；而底侵型埃达克岩源于底侵的幔源玄武质物质，形成于后造山环境。两类埃达克岩及其组合岩石的地质及地球化学特点，展示了中亚型造山在本区晚古生代陆壳增生作用的多样性：在增生构造过程上，有洋壳板片的斜俯冲、俯冲板片的撕裂、板片窗、俯冲剥蚀及玄武质物质的底侵作用等；在增生方向上，有洋壳板片的侧向斜俯冲，也有玄武质物质垂向上底侵于壳-幔边界；在增生物质上，有洋壳板片、地幔楔、受地幔楔混染的洋壳板片熔体，弧前棱柱、地幔楔受板片熔体交代后形成熔体及底侵的幔源玄武质物质。与两类埃达克岩有关，尤其是第一类埃达克岩及其组合岩石，在本区广泛发育了Cu、Au成矿作用，其中部分达到大型-超大型规模。因此．对埃达克岩及其组合岩石的识别及相关Cu、Au成矿作用的找矿勘探应予以足够重视。     

使用VMware模拟双机HA环境及其应用前景

介绍使用虚拟计算机的概念和发展现状及VMware主要产品的区别,对于VMware的3个主要产品Work-station、GSX Server和ESX Server,给出了合理的使用建议,并论述了采用虚拟机所带来的好处以及在国家气象信息中心的应用前景。该文还介绍了VMware GSX Server的使用方法和注意事项。最后通过逐步的讲解,实现了一个虚拟的Suse Linux双机加共享存储阵列的高可用测试(HA)环境,以替代现实中昂贵的硬件环境。     

Single GPS receiver time-relative positioning with loop misclosure corrections

Time-relative positioning makes use of observations taken at two different epochs and stations with a single global positioning system (GPS) receiver to determine the position of the unknown station with respect to the known station. The limitation of this method is the degradation over time of the positioning accuracy due to the temporal variation of GPS errors (ionospheric delay, satellite clock corrections, satellite ephemerides, and tropospheric delay). The impact of these errors is significantly reduced by adding to the one-way move from the known to the unknown station, a back move to the known station. A loop misclosure is computed from the coordinates obtained at the known station at the beginning and at the end of the loop, and is used to correct the coordinates of the unknown station. The field tests, presented in this paper, show that using the loop misclosure corrections, time-relative positioning accuracy can be improved by about 60% when using single frequency data, and by about 40% with dual frequency data. For a 4-min processing interval (an 8-min loop) and a 95% probability level, errors remain under 20 cm for the horizontal components and 36 cm for the vertical component with single frequency data; and under 11 cm for the horizontal components and 29 cm for the vertical component with dual frequency data.     

Turbulence Scale Dependence of the Richardson Constant in Lagrangian Stochastic Models

We investigate the relative dispersion properties of the well-mixed class of Lagrangian stochastic models. Dimensional analysis shows that, given a model in the class, its properties depend solely on a non-dimensional parameter, which measures the relative weight of Lagrangian-to-Eulerian scales. This parameter is formulated in terms of Kolmogorov constants, and model properties are then studied by modifying its value in a range that contains the experimental variability. Large variations are found for the quantity, g* = 2gC₀^{− 1}, where g is the Richardson constant.     

金矿的地质地球化学找矿标志

地层和岩浆岩含金高丰度是金矿赋集的物质来源,断裂构造是容矿、储矿的空间。一般说来,金成矿物质越丰富,就越有利于形成大矿、富矿。以江西金矿找矿为例,阐述正确圈定金异常,合理布置探矿工程,获得找金成果新突破的实际意义。     

Control of wind strength and frequency in the Aral Sea basin during the late Holocene

Changing content of detrital input in laminated sediments traced by XRF scanning and microfacies analyses reflect prominent variations in sedimentation processes in the Aral Sea. A high-resolution record of titanium from a core retrieved in the northwestern Large Aral Sea allows a continuous reconstruction of wind strength and frequency in western Central Asia for the past 1500 yr. During AD 450–700, AD 1210–1265, AD 1350–1750 and AD 1800–1975, detrital inputs (bearing titanium) are high, documenting an enhanced early spring atmospheric circulation associated with an increase in intensity of the Siberian High pressure system over Central Asia. In contrast, lower titanium content during AD 1750–1800 and AD 1980–1985 reflects a diminished influence of the Siberian High during early spring with a reduced atmospheric circulation. A moderate circulation characterizes the time period AD 700–1150. Unprecedented weakened atmospheric circulation over western Central Asia are inferred during ca. AD 1180–1210 and AD 1265–1310 with a considerable decrease in dust storm frequency, sedimentation rates, lamination thickness and detrital inputs (screened at 40-μm resolution). Our results are concurrent with changes in the intensity of the Siberian High during the past 1400 yr as reported in the GISP2 Ice Core from Greenland.     

On-going orogeny in the outer-arc of the Timor–Tanimbar region, eastern Indonesia

The Timor–Tanimbar islands of eastern Indonesia form a non-volcanic arc in front of a 7 km deep fore-arc basin that separates it from a volcanic inner arc. The Timor–Tanimbar Islands expose one of the youngest high P/T metamorphic belts in the world, providing us with an excellent opportunity to study the inception of orogenic processes, undisturbed by later tectonic events.Structural and petrological studies of the high P/T metamorphic belt show that both deformation and metamorphic grade increase towards the centre of the 1 km thick crystalline belt. Kinematic indicators exhibit top-to-the-north sense of shear along the subhorizontal upper boundaries and top-to-the-south sense in the bottom boundaries of the high P/T metamorphic belt. Overall configuration suggests that the high P/T metamorphic rocks extruded as a thin sheet into a space between overlying ophiolites and underlying continental shelf sediments. Petrological study further illustrates that the central crystalline unit underwent a Barrovian-type overprint of the original high P/T metamorphic assemblages during wedge extrusion, and the metamorphic grade ranged from pumpellyite-actinolite to upper amphibolite facies.Quaternary uplift, marked by elevation of recent reefs, was estimated to be about 1260 m in Timor in the west and decreases toward Tanimbar in the east. In contrast, radiometric ages for the high P/T metamorphic rocks suggest that the exhumation of the high P/T metamorphic belt started in western Timor in Late Miocene time and migrated toward the east. Thus, the tectonic evolution of this region is diachronous and youngs to the east. We conclude that the deep-seated high P/T metamorphic belt extrudes into shallow crustal levels as a first step, followed by doming at a later stage. The so-called ‘mountain building’ process is restricted to the second stage. We attribute this Quaternary rapid uplift to rebound of the subducting Australian continental crust beneath Timor after it achieved positive buoyancy, due to break-off of the oceanic slab fringing the continental crust. In contrast, Tanimbar in the east has not yet been affected by later doming. A wide spectrum of processes, starting from extrusion of the high P/T metamorphic rocks and ending with the later doming due to slab break-off, can be observed in the Timor–Tanimbar region.