西秦岭北缘断裂带新活动特征

在本文中，作者在近几年进行的大比例尺活断层地质填图工作的基础上，介绍了西秦岭北缘断裂带晚第四纪以来活动的基本待征，研究了该断裂带的空间展布情况、几何学和运动学特征、断层活动速率、古地震与地震重复周期等。结果表明，该断裂带自第四纪以来由压性逐渐演变为左旋扭动，其水平滑动速率为２．１－２．８ｍｍ／年，垂直滑动速率为０．４－０．７ｍｍ／年，地震复发周期约为５０００年。     

Metamorphic fluid origins in the Osborne Fe oxide–Cu–Au deposit,Australia: evidence from noble gases and halogens

The Osborne iron oxide–copper–gold (IOCG) deposit is hosted by amphibolite facies metasedimentary rocks and associated with pegmatite sheets formed by anatexis during peak metamorphism. Eleven samples of ore-related hydrothermal quartz and two pegmatitic quartz–feldspar samples contain similarly complex fluid inclusion assemblages that include variably saline (<12–65 wt% salts) aqueous and liquid carbon dioxide varieties that are typical of IOCG mineralisation. The diverse fluid inclusion types present in each of these different samples have been investigated by neutron-activated noble gas analysis using a combination of semi-selective thermal and mechanical decrepitation techniques. Ore-related quartz contains aqueous and carbonic fluid inclusions that have similar ⁴⁰Ar/³⁶Ar values of between 300 and 2,200. The highest-salinity fluid inclusions (47–65 wt% salts) have calculated ³⁶Ar concentrations of approximately 1–5 ppb, which are more variable than air-saturated water (ASW = 1.3–2.7 ppb). These fluid inclusions have extremely variable Br/Cl values of between 3.8 × 10⁻³ and 0.3 × 10⁻³, and I/Cl values of between 27 × 10⁻⁶ and 2.4 × 10⁻⁶ (all ratios are molar). Fluid inclusions in the two pegmatite samples have similar ⁴⁰Ar/³⁶Ar values of ≤1,700 and an overlapping range of Br/Cl and I/Cl values. High-salinity fluid inclusions in the pegmatite samples have 2.5–21 ppb ³⁶Ar, that overlap the range determined for ore-related samples in only one case. The fluid inclusions in both sample groups have ⁸⁴Kr/³⁶Ar and ¹²⁹Xe/³⁶Ar ratios that are mainly in the range of air and air-saturated water and are similar to mid-crustal rocks and fluids from other settings. The uniformly low ⁴⁰Ar/³⁶Ar values (<2,200) and extremely variable Br/Cl and I/Cl values do not favour a singular or dominant fluid origin from basement- or mantle-derived magmatic fluids related to A-type magmatism. Instead, the data are compatible with the involvement of metamorphic fluids that have interacted with anatectic melts to variable extents. The ‘metamorphic’ fluids probably represent a mixture of (1) inherited sedimentary pore fluids and (2) locally derived metamorphic volatilisation products. The lowest Br/Cl and I/Cl values and the ultra-high salinities are most easily explained by the dissolution of evaporites. The data demonstrate that externally derived magmatic fluids are not a ubiquitous component of IOCG ore-forming systems, but are compatible with models in which IOCG mineralisation is localised at sites of mixing between fluids of different origin. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

对我国35年来珠峰高程测定成果的思考

20世纪60年代以来，我国曾单独或与外国合作，在1966年，1975年，1992年，1998年及1999年对珠穆朗玛峰高程进行了5次测定，开展了大规模的大地测量外业作业、数据处理和科学研究，其中包括天文、重力、平面、高程和气象等方面。本文对我国近35年来的珠峰高程测定的成果和最新进展作分析研究，将我国35年来所精确测定的珠峰峰顶雪面高程值取中数，以我国60(似)大地水准面为基准面，得珠峰海拔高为8849.0m±0.5m；若以接近全球高程系统的EGM96大地水准面为基准面，珠峰海拔高为8850.1m±0.5m。     

珠峰及邻近区域第四次大地测量

叙述了我国大地测量工作者于 1998年对珠穆朗玛峰及邻近区域进行的第四次大规模的大地测量外业概况和取得的成果 ,以及数据处理方法和最终结果。经过对 1998、196 6 - 196 8、1975、1992年珠峰及邻近区域四次大地测量数据综合分析 ,从地学方面进行研究 ,得出青藏块体在印度板块的推动下 ,仍向北东东方向运动 ;珠峰地区相对垂直运动在整体抬升的过程中伴有波浪式的起伏等结论。     

滇中南无量山种子植物区系联系及其地位

无量山种子植物区系迄今为止含207科,1027属,2548种,极其丰富,通过对区系相似性系数、云南各自然小区的共有种频率以及中国特有属三方面的分析,把无量山置于东亚植物区的中国-喜马拉雅森林植物亚区的云南高原地区。     

Mobility of rare-earth elements and copper during shear-zone-related retrograde metamorphism

In Mid Proterozoic crystalline rocks of the Mount Isa Inlier, around Cloncurry, Australia, 2000 km² of alteration and brecciation are the product of high-temperature (> 450 °C) concentrated saline solution activity. During retrogression, this fluid was locally responsible for mobility of V, Y, Nb and light rare-earth elements (15 × enrichment). Copper and S were leached during alteration and this may have been a significant source of components in nearby Cu-Au deposits. Similar rare-earth-element behaviour has been observed in the hematite breccias which host Cu-sulfides at the giant Olympic Dam Cu-Au deposit.     

大别山东、北段热量资源短期考察资料的序列延长

本文根据三个月的短期气温资,利用自然止交函数展开和最小二乘方法按不同季节分别对大别山东段和北段的气温资料进行延长,得到了该地区一年内的旬平均气温,其相对误差在4.1%—13.9%之间。     

Mt. Etna volcano high-resolution topography: airborne LiDAR modelling validated by GPS data

High-resolution digital topography is essential for land management and planning in any type of territory as well as the reproduction of the Earth surface in a geocoded digital format that allows several Digital Earth applications. In a volcanic environment, Digital Elevation Models are a valid reference for multi-temporal analyses aimed to observe frequent changes of a volcano edifice and for the relative detailed morphological and structural analyses. For the first time, a DTM (Digital Terrain Model) and a DSM (Digital Surface Model) covering the entire Mt. Etna volcano (Italy) derived from the same airborne Light Detection and Ranging (LiDAR) are here presented. More than 250 million 3D LiDAR points have been processed to distinguish ground elements from natural and anthropic features. The end product is the highly accurate representation of Mt. Etna landscape (DSM) and ground topography (DTM) dated 2005. Both models have a high spatial resolution of 2?m and cover an area of 620?km². The DTM has been validated by GPS ground control points. The vertical accuracy has been evaluated, resulting in a root-mean-square-error of ±?0.24?m. The DTM is available as electronic supplement and represents a valid support for various scientific studies.     

长白山森林植被的生态气候学指标

在全球变化和植被与气候关系的研究中侧重与大尺度、宏观的抽象研究，对小尺度、微观的具体地段植被与气候关系的研究则即地生态气候的研究尚待深入。本文在建立生态气候学指标的基础上，应用桑斯威特（C.W.Thornthwaite)的方法对长白山森林植被的空间分布进行了定量分析。计算了长白山不同坡向不同高度的温度效率指数。根据30个主要树种的温度效率指数，确定了长白山不同坡向的各植被垂直带的温度效率指数及分布高度。并利用AreGIS8.1软件做长白山1：1000000的DEM图，得到长白山不同坡向各垂直带植被与温度效率指数的关系图。     

一场典型的冰雪雨水泥石流过程

1989年7月26日,贡嘎山东坡南关沟发生了一场典型的冰雪雨水泥石流。它下行30多公里后堵塞大渡河,造成直接经济损失245万元。这场泥石流历时约3小时,持续流动时间2小时。到达大渡河时的流速9.4米/秒,最大流量6768.0立方米/秒,总径流量1716.4万立方米,总输沙量627.0万立方米,残留沉积物总方量310.4万立方米(其中泥石流堵塞大渡河的扇形地方量30.0万立方米),弯道爬高15.5—16.5米。输往堵河扇形地下游方的固体物质方量是扇形地方量的19.9倍,泥石流尾流作用强烈。