Mineralogy, petrology and P–T–t path of Ca–Na amphibole assemblages, Saint-Martin des Noyers formation, Vendée, France

Abstract The Saint-Martin des Noyers Formation is interpreted as a slice of an island-arc system of Lower to Middle Palaeozoic age, located in the internal part of the Variscan orogen in Vendée (Armorican Massif, France). Metamorphosed igneous rocks range in composition from ultramafic to rhyolitic. The regular increase in the FeO/(FeO+MgO) ratio, from mafic to silicic samples, results in a systematic variability in the nature and composition of the metamorphic phases. In basaltic samples, the occurrence of relict garnet-barroisite assemblages suggests relatively high-pressure conditions for the peak of metamorphism. During a subsequent retrograde evolution, the primary barroisitic hornblendes recrystallized to texturally complex mixtures of actinolite and hornblende. Despite this complication, it is possible to decipher a P–T-t path based on amphibole chemistry. The P–T trajectory deduced is dominated by the effect of pressure and consistent with early underthrusting and subsequent tectonic uplift of the ancient arc of Saint-Martin des Noyers.     

Saraswati Nadi in Haryana and its linkage with the Vedic Saraswati River — Integrated study based on satellite images and ground based information

Detailed studies on the status of Saraswati Nadi of northern Haryana have been carried out using multi date and multi resolution satellite images, GIS techniques and ground data. Palaeochannels have been delineated using remote sensing techniques and validated using discovered archaeological sites, sedimentological data from drilled wells and water quality data. Detailed analysis of hydrological data (rainfall and stream discharge), catchment area and petrographic analysis of rock samples have been done to decipher the dwindling state of Saraswati Nadi. Likelihood of Adi Badri as the place of origin of Saraswati Nadi and its possible linkage with the Vedic Saraswati River is discussed. Suggestions have been given for safeguarding and revival of Saraswati Nadi as a national heritage.     

腾冲盆地阻水构造的发现

腾冲来凤山北麓前缘,潜伏一段阻水构造——地下水位坡降带。从研究13个水文钻井、119口民间井、2个泉水露头地下水位特征入手,采用古水文和现代水文地质研究方法,论证此段阻水构造的存在。     

遥感影像快速正射处理系统测试方案探讨

在Ortho系统发布前的软件测试中设计了一套测试方案,按照该方案中的测试路线和方法,通过采用各种基础资料进行试生产和与PCI软件的比对,测定了Ortho系统存在的缺陷和不足,并结合实际情况,给出了恰当的分析意见和验证了方案的正确性。     

基于遥感与GIS的于田绿洲土地覆盖动态研究

在完成于田绿洲图像库和矢量数据库的基础上,通过遥感与GIS技术,研究了近10a于田地区的土地覆盖类型变化,并结合历年实地考察结果,分析了该地区的环境变化和荒漠化程度,研究结果对西部干旱区绿洲的环境演变和可持续发展研究,具有现实意义。     

RS技术在实时区域土壤侵蚀评价中的应用--以福建省花山溪流域为例

传统数据采集方法严重制约了土壤侵蚀评价实时、快速的要求。文章以福建花山溪流域为例,基于“通用土壤侵蚀方程式”(USLE)为土壤侵蚀定量评价模型,利用多时效、多光谱的遥感数据,在ERDAS8．5软件平台上,研究提取流域动态最易变化的植被、土地利用类型等信息的技术方法。研究结果证实,这种方法可以快速、准确地提取影响土壤侵蚀的基本参数．进而实现对区域流域土壤侵蚀的实时评价。     

基于粗糙集的K--均值聚类算法在遥感影像分割中的应用

结合粗糙集理论和K——均值聚类算法，提出一种遥感影像的粗糙聚类分割方法。根据遥感影像中特征属性的相互依赖关系，应用粗糙集理论的等价关系。求出K——均值聚类所需要的初始类的个数和均值。然后采用聚类算法对图像进行分割。实验结果表明该方法比随机选取聚类的中心点和个数减少了运算量．提高了分类精度和准确性。     

赤水油气遥感直接探测意义与TM选择及分类分析

本文以赤水油气遥感为例，说明油气直接探测的意义,选择TM数字磁带资料作为提取油气遥感信息源的原因，经计算机图象处理，将直接提取出的遥感信息分类，排除油气遥感无用信息，保留其有用信息，图出有可能的天然气远景区，为进一步油气勘探提供科学依据。     

Organic geochemistry and petrology of barren and Mo–Ni–PGE mineralized marine black shales of the Lower Cambrian Niutitang Formation (South China)

Marine black shales of the Lower Cambrian Niutitang Formation in southern China host Mo–Ni–platinum group elements (PGE) mineralization confined to a phosphate- and pyrite-rich stratiform body (max. 20-cm thick). The H/C atomic ratio, carbon isotopic composition, FTIR spectra of bulk organic matter, and spectra of extractable part of organic matter indicate similar sources and thermal evolution of organic matter in barren and mineralized black shales.The morphology and relative abundance of organic particles in barren and mineralized shales are different. In barren black shales, organic particles comprise only elongated bodies and laminae 2–10 μm across or elongated larger bodies (> 10 μm) with R_max = 2.96–5.21% (Type I particles). Mineralized black shales contain Type I particles in rock matrix (90–95 vol%), small veinlets or irregular organic accumulations (Type II particles, 1–5 vol%) that display weak to well developed mosaic texture and a variable reflectance (R_max = 3.55–8.65%), and small (< 1 to 5 μm) rounded or irregular Type III organic particles (1–4 vol%) distributed within phosphate nodules and sulphide rip-up clasts. Type III particles show similar reflectance as particles of Type I in rock matrix. Type I particles are interpreted as remnants of in situ bacterially reworked organic matter of cyanobacteria/algal type, Type II as solidified products or oil-derived material (migrabitumen), and Type III particles as remnants of original organic matter in phosphatized or sulphidized algal/microbial oncolite-like bodies. Equivalent vitrinite reflectances of Type I and III particles in barren and mineralized rocks are similar and correspond to semi-anthracite and anthracite. Micro-Raman spectra of organic particles in rocks display a wide belt in the area of 1600 cm^− 1 (G belt) and approximately the same belt in the area of 1350 cm^− 1 (D belt). The ratio of integrated areas of the two belts correlate with R_max values.The Mo–Ni–PGE mineralized body is interpreted as to represent a remnant of phosphate- and sulphide-rich subaquatic hardground supplied with organic material derived from plankton and benthic communities as well as with algal/microbial oncolite-like bodies that originated in wave-agitated, shallow-water, nearshore environment.     

增长曲线模型中线性估计类所有可容许估计

对增长曲线模型中回归矩阵的函数的线性估计进行了研究。在矩阵损失下 ,作者得到了线性估计在一切线性估计类中可容许的充要条件