Numerical modeling of 3-D terrain effect on MT field

Using the boundary element method, the numerical modeling problem of three-dimensional terrain effect on magnetotelluric (MT) field is solved. This modeling technique can be run on PC in the case of adopting special net division. The result of modeling test for 2-D terrain by this modeling technique is basically coincident with that by 2-D modeling technique, but there is a great difference between the results of 3-D and 2-D modeling for 3-D terrain. Project supported by the National Natural Science Foundation of China.     

Geochemical constraints on the petrogenesis of basalts from eastern Jiangnan orogen, South China

The basalts crop out widely in the eastern part of late Proterozoic Jiangnan orogen. In terms of their petrographical and geochemical characteristics, they can be divided into two distinct types: low- and high-Ti. basalts. They crystallized from the magmas derived from the depleted upper mantle differing in partial melting degree. Project supported by the National Natural Science Foundation of China.     

强余震持续时间的早期估计

本研究旨在解决地震序列中强余震持续时间的早期估计问题。文中首先给出了强余震的震级定义，指出：主震型与强震群型序列的强作震持续时间存在差异。使用模式识别方法对主震型序列中强余震持续时间大于１天，小于１天及无强余震等３种情况进行划分之后，给出了两类序列的强余震持续时间与序列和第一震震级的粗略相关关系。     

云南岩石圈热结构

本文探讨了云南深部热流及岩石圈地温分布的横向变化特征，并将岩石圈热结构概括为３种类型；典型现代构造活动区热结构，中间过渡型地质区热结构和稳定地质区热结构。最后，简单讨论了地热与地震活动的关系。     

陆相渐新统划分中的问题及新进展

近年来国际上关于始新世－渐新世界线的研究取得了重大进展，其同位素年龄被确认为３４Ｍａ，北美哺乳动物年代表已据此重新厘定。通过对哺乳动物群的分析和对比，论证了我国原认为是早渐新世的乌兰戈楚期和呼尔井期的时代应改归晚始新世，原认为是中渐新世的三达河期的时代应为早渐新世。在亚洲始新世－渐新世的界线不是在乌兰戈楚期之末，而是在呼尔井期与三达河期之间。     

苏州地区I-A型花岗岩特征与成因的对比研究

应用岩石学、矿物学、地球化学及岩浆物理学等的理论和方法，对苏州地区Ｉ型和Ａ型花岗岩的特征及成因进行了对比研究，得出以下主要结论：Ｉ型花岗岩为晚侏罗世火山弧压性环境产物，侵位较深；而Ａ型者为Ａ２型花岗岩，为早白垩世造山后张性环境产物，侵位较浅，具晶洞构造．Ａ型比Ｉ型花岗岩以酸度、碱度、Ａｌ，Ｆ含量高而Ｈ２Ｏ＋含量低，以ＲＥＥ及不相容元素丰度高，负Ｅｕ异常强，而ｗ（ＬＲＥＥ）／ｗ（ＨＲＥＥ）低为特色．Ａ型者矿物结晶顺序先浅色后暗色，暗色矿物以富铁贫镁、ＲＥＥ分配系数高及负Ｅｕ异常明显及长石富碱贫钙，而与Ｉ型花岗岩不同．Ａ型者副矿物４０余种，属锆石－褐帘石－萤石型，锆石结晶温度高，（１１０），（１１１）晶面发育；而Ｉ型者仅１０余种，属榍石－锆石－磷灰石型，锆石结晶温度低，（１００），（３１１）晶面发育．Ｉ型花岗岩为幔源岩浆与下地壳部分熔融岩浆混合及ＡＦＣ作用产物，而Ａ型花岗岩为残余下地壳（麻粒岩相）熔融后分离结晶产物，二者并非同源岩浆演化关系．Ａ型比Ｉ型岩浆来源浅，酸度大，含水少；故岩浆密度小，粘度大，上升慢，冷凝长．受密度筛影响，Ａ型花岗岩岩浆房及侵位深度小于Ｉ型     

格子Boltzmann方法地震波场模拟

格子Ｂｏｌｔｚｍａｎｎ方法是细胞自动机在某些学科中的具体化和应用。它根据微观运动过程的某些基本特征建立简化的、时间和空间完全离散的动力学模型，这种模型的平行行为符合宏观的微分方程。     

The Discovery of Phlogopite Exsolution Lamellae in Garnets of Eclogite Inclusions, Liaoning Province

In No. 50 kimberlite pipe of Fuxian County, Liaoning Province, an eclogite inclusion(nodule), which is extremely rare in kimberlites, was discovered and phlogopite exsolutionlamellae were found in garnets of the inclusion. Microscopic, TEM and energy spectral observa-tions and studies confirmed that these lamellae are phlogopite. They are colourless and acicularin section, generally 0.5-5μm in width and 10-100μm in length. Nevertheless, fine lamellae,0.05-0.1μm wide and 1-2μm long, are also well developed. Along [111] of the garnet, three setsof phlogopite lamellae show oriented arrangement approximately at angles of 60°-70°, indi-cating that these lamellae might be the product of exsolution from garnet as a result ofpressure-release when eclogite ascended from the relatively deep level to the relatively shallowlevel of the mantle. Tiny acicular exsolution minerals (or inclusions) are commonly found ingarnet and pyroxene in eclogite inclusions of kimberlites all over the world and it has been re-ported that the identified exsolution minerals include pyroxene and rutile. This is the first timethat phlogopite exsolution lamillae were found in eclogite inclusions in the world.     

Mineralization Ages of the Jiapigou Gold Deposits,Jilin

The Jiapigou gold deposits are typical vein type deposits associated withArchaean greenstone belts in China. According to the crosscutting relationships between dykesand auriferous veins, single hydrothermal zircon U-Pb dating and quartz K-Ar,~(40)Ar-~(39)Ar andRb-Sr datings, the main mineralization stage of the Jiapigou deposit has been determined to be2469-2475 Ma, while mineralization superimposition on the gold deposit occurred in1800-2000 Ma and 130-272 Ma. They form a mineralization framework of one oldermetallogenic epoch (Late Archaean-Early Proterozoic) and one younger metallogenic epoch(Mesozoic) of gold deposits in Archaean greenstone belts in China.     

福建省东部及邻区岩浆活动的构造环境与热变质作用

研究区自加里东期运动以来，经历了复杂的构造－岩浆－热演化过程。在分析岩浆活动特征及其形成的构造环境的基础上，探讨了研究区沉积岩系及其中有机质的热变质作用。