The New Meteorite Fall of Yanzhuang—A Severely Shocked H6 Chondrite with Black Molten Materials     

Xiande Xie  Zhaohui Li  Daode Wang  Jingfa Liu  Ruiying Hu  Ming Chen 《中国地球化学学报》1994,13(1):39-46

At 21:45 hr (Beijing time) on Oct. 31, 1990 the Yanzhuang meteorite hit the ground at the Yanzhuang village, Wenyuan County, Guangdong Province. Several fragments, totalling 3.5 kg, were recovered during the field survey. This meteorite is a rare one of its kind due to its heavily shocked features and thick veins made up of black molten materials. Olivine and low-calcium pyroxene are compositionally homogeneous with Fa=18.59, Fs=16.35 and Wo=1.29. The chemical composition (total Fe=28.0%) and recrystallized texture of the chondritic mass show that the Yanzhuang is an H6 chondrite. The black molten materials occur in the form of blocks (up to 2×3×4 cm in size) and veins (0.1–15 mm in width), and contain a lot of rounded and elliptic FeNi-FeS blobs (up to 6–10 mm in length). The metal in these blobs exhibits distinct dendritic structure characteristic of rapid cooling. Unmolten and molten samples are very similar in chemical composition, fitting well with the average H-chondrites. Partial melting and FeNi/FeS-silicate separation have not been observed in the molten materials of the Yanzhuang. This project was financially supported by the Science Foundation of Guangdong Province.  相似文献   

On the enhanced confining pressure aproach to the mechanics of reinforced soil     

G. A. Athanasopoulos 《Geotechnical and Geological Engineering》1994,12(2):122-132

Summary A review is presented of conceptual approaches that are currently in use for interpreting the operation of reinforced soil. The concepts of enhanced confining pressure and of reduced normal tensile strains are found to be closely related to current experimental and theoretical investigations as well as to the design methodologies available at present for reinforced soil applications. Focusing on the enhanced confining pressure concept, analytical expressions are developed that allow the estimation of the value of equivalent confining stress increase when the properties of soil and reinforcement and the state of stresses acting on a cylindrical reinforced soil element are known. The derived expressions can also be utilized for estimating the soil-reinforcement friction angle from the results of triaxial tests on cylindrical samples reinforced with horizontal layers of reinforcement.  相似文献   

Aggregate resources: Production and environmental constraints     

R. Poulin  R. C. Pakalnis  K. Sinding 《Environmental Geology》1994,23(3):221-227

Aggregates are produced from sand and gravel deposits or from bedrock sources. Production sites are numerous to minimize transport and are more and more in a competing land use position. Urbanization, while creating a market, also sterilizes deposits and pressures producers to relocate further from populated areas. Regulating and permitting quarries is an issue in regions with growing populations. This regulatory environment may cause exploitation schemes to evolve towards greater recycling, importing, and marine production, for example. These changes may be entirely attributable to increased environmental constraints on producing operations and not on conventional mining constraints such as overburden, ore grade, and costs of operation.  相似文献   

北秦岭灰池子花岗岩基成岩物质来源探讨   总被引：3，自引：0，他引：3  

张宏飞  骆庭川 《矿物岩石》1994,14(1):67-73

本文主要通过Ｎｄ，Ｓｒ和Ｏ同位素示踪研究，分析了灰池子花岗岩基的成岩物质来源，初步查明该岩体的岩浆源区由６９％的地幔物质和３１％的陆壳物质混合而成，属壳幔型花岗岩。  相似文献   

某些方解石单晶的光学质量评价     

黄德群 《矿物学报》1986,(4)

本文用光学方法检查了经野外地质工作者挑选过的天然方解石单晶的光学质量。发现部分晶体的光学均匀性很差,晶体中的光散射颗粒很多,不能满足作为光学介质的要求。  相似文献   

陕西柞水—山阳成矿带中酸性小岩体的地球化学研究   总被引：2，自引：0，他引：2  

Li Zejiu 《地球科学》1986,(4)

本成矿带内中酸性小岩体均为浅成—超浅成相、高温条件下岩浆结晶的产物。根据岩体及矿床中硫同位素、铅同位素成分及全岩稀土元素组成特征,判断成岩物质来源于地壳深部或上地慢。来自岩浆熔体的热水溶液是导致成矿的重要因素。  相似文献   

The importance of atmospheric input of terrestrial organic material to deep sea sediments     

Robert B. Gagosian  Edward T. Peltzer 《Organic Geochemistry》1986,10(4-6)

The concentrations of lipids were determined in atmospheric particle, gas and rain samples collected from the tropical North Pacific to assess lipid sources, transport mechanisms and fluxes to the ocean surface. Four lipid compound classes (aliphatic hydrocarbons, fatty alcohols, fatty acid esters, and salts) all unequivocally show a terrestrial vascular plant source. These aerosol lipids originate from wind erosion of Asian and American soils and direct emission from vegetation. The major fluxes result from rain rather than dry deposition. These fluxes are large enough to have a major potential impact on the inventory of terrestrially derived lipid material found in deep-sea sediments. This has been showm for n-alkanes, fatty alcohols, fatty acids, total lipids and for organic carbon. By comparing atmospheric and sediment trap fluxes with sediment accumulation rates, it is suggested that some biogenic terrestrial material is more protected from degradation than marine-derived material.  相似文献   

论太行山构造岩浆带的岩浆来源及其成因   总被引：8，自引：0，他引：8  

牛树银  董国润 《地质论评》1995,41(4):301-310

本文以太行山构造岩浆带及其东西两侧断陷盆地的地质特征及深部探测资料为依据，探讨远离俯冲板内构造岩浆带中岩浆的成因、来源及侵位机制。提出了韧性流变－岩浆隆起模式。认为在区域构造应力场和地幔位势差、密度差的控制下?隆升的造山带剥蚀物向两侧断陷盆地搬运，而中下地壳则沿深部向山根缓倾的韧性拆离带迁移到造山带的深部，并在拆离剪切作用及流体的参与下形成深熔岩浆，这种深熔岩浆，在沿陡倾剪切带上侵过程中，不断与中  相似文献   

安太堡露天煤矿排土场基底黄土的微结构演化与弱层的形成机理          下载免费PDF全文

陈敏 《地质论评》1995,41(6):571-576

本文根据安太堡露天煤矿排土场基底黄土的粘土矿物组成的微结构及其在分级荷载下微结构变化的研究，论述了排土场基底黄土内弱层的形成机理，提出弱层是在上覆排土压力下由于黄土的微结构变化而形成的演化弱层。并指出弱层的形成是导致排土场失稳滑坡的主要控制因素，这种弱层在新排土场设计时期并不存在，极具隐蔽性，但在设计时必须考虑在排土增至一定高度后，弱层的形成对排土场稳定性的影响，否则必将会存在重大滑坡隐患。  相似文献   

关于生命起源研究的问题及其主攻方向的探讨   总被引：1，自引：0，他引：1  

王将克  钟月明 《地球科学进展》1995,10(2):196-201

本文综述和分析了近几十年来国内外关于生命起源的研究的问题及各种假说和见解，提出物质的起源是生命起源问题研究的核心，生命起源问题应是研究原始地球的非生命物质如何演变成为生命物质的，地球上分子手性的起源是生命起源问题研究的主攻方向，有机分子光学活性百发生在由化学进化转入生物进化这一过渡阶段。  相似文献