现代土壤湿度测量方法的评价和问题

本文对土壤湿度测量方法的研究状况作了简要分析。研究了进一步改进恒温称重法的可能性;提到了湿度测量中应用“核磁共振”法的可能性;对适合线路观测需要的轻便湿度表的研究,例如很有前途的介电法进行了分析。     

Constraints of Mantle and Crustal Sources Interaction during Orogenesis of Pre- and Post-collision Granitoids from the Northern Arabian-Nubian Shield: A Case Study from Wadi El-Akhder Granitoids,Southern Sinai,Egypt

The Egyptian older and younger granitic rocks emplaced during pre- and post-collision stages of Neoproterozoic Pan-African orogeny, respectively, are widely distributed in the southern Sinai Peninsula, constituting 70% of the basement outcrops. The Wadi El-Akhder, southwestern Sinai, is a mountainous terrain exposing two granitoid suites, namely the Wadi El-Akhder Older Granites (AOG) and the Homra Younger Granites (HYG). The AOG (granodiorites with subordinate tonalite compositions) have geochemical characteristics of medium-K calc-alkaline, metaluminous to mildly peraluminous granitoids formed in an island-arc environment, which are conformable with well-known Egyptian older granitoids rocks, whereas the HYG display calc-alkaline to slightly alkaline nature, peraluminous syeno-, monzogranites and alkali feldspar granites matching well those of the Egyptian younger granites. With respect to the AOG granitoids, the HYG granites contain lower Al2O3, FeO*, MgO, MnO, CaO, TiO2, Sr, Ba, and V, but higher Na2O, K2O, Nb, Zr, Th, and Rb. The AOG are generally characterized by enrichment in LILE and LREE and depletion in HFSE relative to N-MORB values (e.g., negative Nb and Ta anomalies). The geochemical features of the AOG follow assimilation-fractional crystallization (AFC) trends indicative of extensive crustal contamination of magma derived from a mantle source. The chemical characteristics of the AOG are remarkably similar to those of subduction-related granitoids from the Arabian-Nubian Shield (ANS). The compositional variations from monzogranites through syenogranites to alkali feldspar granite within HYG could not be explained by fractional crystallization solely. Correlating the whole-rock composition of the HYG to melts generated by experimental dehydration melting of meta-sedimentary and magmatic rocks reveals that they appear to be derived by extended melting of psammitic and pelitic metasediments, which is similar to the most of younger granitic suites in the ANS.     

掩盖区比例尺1:200000地质测量

正如规范和方法指南中所规定的那样,此例尺1:200000地质测量的目的,是全面查明某一地区地质构造,阐明它的地质发展史。详细程度应足以:(1)确定矿产与火成岩变质岩及沉积岩一定组合的关系;(2)查明发现矿产的远景;(3)划出布置更详细的普查或勘探工作的地段。     

关于羣众性水利工程效益及其对徑流影响的某些问題的发言

为了研究羣众性水利工程效益及其对徑流影响,而召开的这次会議无論在內容方面以及目的方面都是世界上任何一个国家里都未曾有过的特殊会議。会議的特点是,研究轟蟲烈烈的全民改造自然运动在水利方面所获得的成果,研究中国人民在进行革命性的征服自然力进而利用过去为害人民的自然力(水利資源)发展国民經济,首先是发展农业当中所获得的成果。     

不同围压下岩石中泊松比的各向异性

由弹性波纵横波速比计算得到的泊松比,在利用地震波反演地下结构和物质组成时,可以提供比单纯地利用纵波或者横波波速更强的约束. 为了研究不同岩石中泊松比及其各向异性随围压的变化,选取19块典型的岩石样品,在不同围压下沿相互正交的3个方向同时测量纵、横波速度,并通过计算得到了泊松比及其各向异性. 结果表明,在大部分样品中泊松比各向异性与纵波速度各向异性有一定的相关性,但在有的样品中泊松比各向异性与纵波速度各向异性没有明显的关系,甚至表现出完全相反的变化规律. 由于泊松比也表现出很强的各向异性,在排除微裂隙的影响后有的仍可以达到30髎以上,在利用实际地震波传播数据通过泊松比反演地下物质结构时必须考虑其各向异性的影响.     

西天山古俯冲带深部流体来源——来自高压变质带內高压脉和主岩的Pb,Sr同位素证据

对西天山高压变质带内高压脉的研究表明, 高压脉与寄主岩石具总体一致的Pb和Sr同位素组成, 高压脉206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb及87Sr/86Sr (t = 340 Ma)分别为17.122~17.431, 15.477~15.611, 37.432~38.689和0.70529~0.70705; 主岩上述比值为17.605~17.834, 15.508~15.564, 37.080~38.145和0.70522~0.70685. 与主岩相比, 高压脉具大得多的Pb同位素组成变化. 高压脉和主岩Rb/Ba, Ce/Pb, Nb/U和Ta/U比值均介于洋岛玄武岩(OIB)或洋中脊玄武岩(MORB)与陆壳间, 显示有陆壳物质混入. 西天山古俯冲带深部成脉流体为来自具I类富集地幔特征的大洋玄武岩(主岩原岩)进变质脱水与来自俯冲沉积物(包括陆源沉积物)进变质脱水形成的两种流体的混合.     

西澳大利亚伊尔冈地块花岗岩—绿岩组合形式的成因

西澳大利亚的伊尔冈地块主要由太古宙椭圆形花岗质岩石区和围绕其边缘呈弧形分布的绿岩带组成。该地体典型部位的露头型式表明,它们起因于大型穹—盆褶皱干涉构造,而不是具有陡立边缘的岩基的底辟侵位。绿岩和下伏花岗质岩石最初是在近水平状态下一起变形的。结果,使花岗质岩石发生重结晶,并形成基本与绿岩层理平行的片麻状构造。近水平且巨厚的二长花岗岩岩席是后来侵入任绿岩系下部层位的,后期变形作用产生两组连续的并相互具高角度垂直轴而的褶皱,它们构成了直径从数匣米到50多公里的穹—盆褶皱干涉构造。     

开发地球物理学的最新进展

当今在石油价格下跌、国内储量减小的情况下,很多公司把注意力都集中在通过精确确定壮年油区、并更详细地描述其特征来提高储量的问题上.经济地质局的分析表明,除了阿拉斯加以外,通过加密钻探、扩展钻探和二次完孔,可使美国大陆的油储量增加800亿桶,汽储量增加180万亿立方英尺.然而这只能在以详细的地质估评为基础时才能实现.因为开发壮年油     

Comparison of Kuqa foreland basin with Persian Gulf Basin in salt tectonics

Compared Kuqa foreland basin with Persian Gulf Basin in development of salt layers, salt tectonics, and the relation between salt tectonics and hydrocarbon, it is concluded that the salt diapirs are relative to hydrocarbon. Searching salt diapirs and related traps in Kuqa foreland basin is important. The forming mechanism of salt tectonic in Kuqa foreland basin is different from that of Hormuz Series, but similar to that of Lower Fars Series/Gachsaran Formation. Inspired by the role of salt tectonics of Lower Fars Series/Gachsaran Formation in hydrocarbon accumulation, the authors considered that the exploration below salt layer should be enforced, and the traps below salt layer in the southern part of the Kuqa foreland basin would be found where salt layer is thicker. On the contrary, the traps should be found both above and below the salt layer in front of the northern mountain where salt layer is thin. The Triassic and Jurassic source rocks are rich in this area with great exploration prospective.