秦岭核桃坝石炭系深水相遗迹化石,沉积环境和古地理分析

研究剖面位于陕西凤县核桃坝，构造上属秦岭造山带的商丹缝合带。核桃坝剖面下部为浅海陆棚相粉砂岩、泥灰岩和灰岩；中、上部以重力流沉积为主。在中部浊积岩中产遗迹化石：Ｎｅｒｅｉｔｅｓ ｆｅｎｇｘｉａｎｅｎｓｉｓ ｉｃｈｎｏｓｐ．ｎｏｖ．，Ａｃａｎｔｈｏｒｈａｐｈｅ ｃｆ． Ａ． ｉｎｃｅｒｔａ Ｋｓｉａｚｋｉｅｗｉｃｚ，Ｃｈｏｎｄｒｉｔｅｓ ｉｃｈｎｏｓｐ．，Ｐｌａｎｏｌｉｔｅｓ ｉｃｈｎｏｓｐ．等。其     

低温条件下有机酸对铁、铜的淋滤实验研究

水／岩作用实验研究表明，在低温条件下柠檬酸、草酸和酒石酸对岩石中的铁、铜都有很高的淋滤率。这表明，在表生地质作用过程中有机酸对成矿元素有很强的活化能力。实验研究同时发现，有机酸对成矿元素的活化能力受其分解温度的限制，由于大部分有机酸的分解温度都在２５０℃以下，因而有机酸对成矿元素的活化仅限于低温条件。本次研究还显示，判断一种岩石能否成为矿源层，不能简单的以其中成矿元素的含量高低作为标准，其中更关键的因素是元素在岩石中的存在形式，如果成矿元素在岩石中难以活化的形式存在，那么含量再高也无法提供成矿物质     

北秦岭南缘弧前盆地沉积作用及盆地发展

秦岭被商丹缝合带分为北秦岭和南秦岭两个部分,在北秦岭南缘残留着与俯冲作用相关的岛弧火山岩以及弧前沉积体。对沿海丹带两个地区(黑河地区和黑山地区)弧前沉积体岩相组合和相序的研究显示,它们主要由深水浊积岩系。火山碎屑岩,扇三角洲沉积以及局限性台地碳酸盐岩和陆棚碎屑岩组成。总的沉积序列显示向上变浅趋势,但在弧前内侧边缘则表现为向上变深趋势。两个不同地区岩相和相序的差异明显受物源、海平面变化以及特别是构造作用的挫制。深水浊积岩系所反映的线状物源供给形式、扇三角洲体系的发育和其内部不同沉积段反复重叠的特征指示一种活动构造环境。弧前区构造发展一方面与其前部加积或下部垫底作用有关,另一方面则在很大程度上受由斜向俯冲而导致的伸展作用的影响。     

The Texture,Mineral Assemblages and Origin of Metamorphic Peridotite from Kuda Ophiolite,Xinjiang

There are two grades of network-type texture in metamorphic peridotite from the Kuda ophiolite,Xinjiang,China,The first graduation consists of coarse-grained olivine with plastic deformation fabrics,orthopyroxene and minor clinopyroxene and Cr-spinel.The second graduation consists of small minerals filling among the mineral grains of the first graduation.Four kinds of assemblages containing tremolite have been discovered in the second graduation,which were formed during mantle partial melting and mantle metasomatism of a highly depleted peridotite.     

丰城洛市地区推,滑覆构造特征及其成因探讨

介绍了洛市地区推、滑覆构造特征、运动学标志及其形成时期、成因模式。     

武夷地区燕山期成矿特征及找矿方向

武夷及邻区燕山期成矿作用在环太平洋成矿带中具有四大特色：（１）成岩成矿在时空上从陆内向陆缘发展；（２）岩浆成矿作用具多层次造浆与多层次就位成矿；（３）华夏系列多字型复合构造控岩控矿；（４）成岩成矿具北北东向向洋分带与纬向分带叠加的“双向”分带。武夷地区是寻找火山－斑岩铜、金、锡、银铅锌等矿产的重要成矿带，又是找寻动热变质或花岗岩－剪切带型金矿床的有利地带。     

Early Estimation of Strong Aftershock Duration Time

In order to solve the problem of early estimation of moderately strong aftershock duration time in an earthquake sequence,this study has been conducted.First,the definition of the strong aftershock has been given.It is pointed out that there is a difference in the strong aftershock duration time between the main shock type sequence and the strong earthquake swarm sequence.After dividing the three cases,i.e.,a strong aftershock duration time larger than 1 day,smaller than 1 day,and no strong aftershock occurred in a main shock type sequence by using the pattern recognition method,we gave the rough correlation relation between strong aftershock duration time and first large shock magnitude for two types of sequences.Finally,the judgment index and method of estimating strong aftershock duration times for different sequence types have been given.     

Attenuation of coda waves and Q c value beneath the Chengdu telemetered seismic network

Based on the single scattering model of coda power spectrum analysis, digital waveform data of 50 events recorded by the real-time processing system of the Chengdu telemetry network are analyzed to estimate the Q _c values of earth medium beneath the Chengdu telemetry network for several specified frequencies. It is found that the Q _c shows the frequency dependency in the form of Q _c = Q ₀ f ⁿ in the range of 1.0 to 20.0Hz. Estimated Q ₀ ranges from 60.83 to 178.05, and n is found to be 0.713 to 1.159. The average value of Q ₀ and n are 117 and 0.978 respectively. This result indicates the strong frequency dependency of the attenuation of coda waves beneath the Chengdu telemetry network. Comparing with the results obtained in other regions of the world, it is found that Q ₀ ⁻¹ value and its change with frequency are similar to those in regions with strong tectonic activity. This subject is supported by the Ministry of Personnel, China for partly sponsoring.     

PREDICTIONS OF CRUSTAL DEFORMATION CAUSED BY CHANGING POLAR ICE ON A VISCOELASTIC EARTH

Changes in polar ice could cause vertical crustal motion of up to several mm yr-1 along the edge of the Greenland and Antarctic ice caps. Measurements of the uplift could help constrain the changing ice volumes. The problem is complicated by the Earth's visco-elastic response to past loading, including the Late Pleistocene deglaciation. A method is described for removing these visco-elastic effects, by using simultaneous measurements of vertical motion and surface gravity. A linear combination of these two measurement types can be formed which is relatively independent of visco-elastic effects, and which can be interpreted in terms of present-day fluctuations in ice.