苏鲁超高压变质带中非超高压花岗质片麻岩的准确识别:来自锆石微区矿物包体及SHRIMP U-Pb定年的证据

通过隐藏在锆石微区矿物包体激光拉曼的系统鉴定和阴极发光图像特征的详细研究,配合相应的锆石微区SHRIMP U-Pb定年测试,发现苏鲁地体超高压变质带中确实存在非超高压变质的花岗质片麻岩。该类岩石中的锆石晶体自核部到边部所保存的矿物包体以不含超高压矿物为特征,相应的阴极发光图像具有典型岩浆结晶锆石的核部和幔部,以及变质的再生边的特点。其中岩浆结晶锆石微区记录的~(238)U-~(206)Pb年龄为404～748Ma,表明原岩中部分锆石可能经历了Pb丢失,也不排除后期热事件因素的影响,原岩的形成年龄应大于748 Ma;而锆石的再生边所记录的~(238)U-~(206)Pb。年龄为204～214 Ma,与研究区经历超高压变质的副片麻岩和花岗质片麻岩锆石微区所记录的苏鲁地体快速折返过程中角闪岩相退变质年龄(~(238)U-~(206)Pb年龄的平均值为211±4 Ma,刘福来等,2003a)十分相似。上述特征表明,苏鲁地体超高压变质带中的部分花岗质片麻岩在超高压变质事件之前就已经形成,但并未“参与”深俯冲—超高压的变质演化过程,而是在苏鲁地体快速折返的角闪岩相退变质过程中与超高压岩片“拼贴”在一起。该项成果不仅为正确识别非超高压变质岩石提供了一个新的研究方法,而且对进一步深入探讨苏鲁地体超高压和非超高压岩片的“拼贴”机制有着重     

Gold Content of Mantle-Derived Rocks from Eastern China and Its Implications

We have analyzed the gold content of 65 samples of mantle-derived xenoliths and their host rocks from eastern China, which is found to be inhomogeneous, falling in the ranges of 1.0×109-8.2×109 (averaging 3.8 ×10-9) and 0.2×10-9-5.3×10-9 (averaging 2.7×10-9) in the mantle-derived xenoliths and the host basalts respectively. Except the samples from Wanquan County of Hebei Province and Anding County of Hainan Province, the gold content is the highest on the margins of the North China platform and decreases spatially towards the north and south, and temporally the samples of the Tertiary have a higher gold content than those of the Quaternary. The gold content of the mantle-derived xenoliths and the host Paleozoic kimberlites is 3.8×10-9-180×109and 0.1×10-9-38.0×10-9 respectively, which are higher than that in the mantle-derived xenoliths in basalt and the host Cenozoic basalts. The mantle-derived xenoliths have a higher gold content than the host rocks, but their relativity is not very clear, su     

A Catalogue of Earthquakes With Moment Magnitude of the Center-Southern Asia Test Area of the Global Seismic Hazard Assessment Program

We compile a regional catalogue of earthquakes with moment magnitude of the Center-Southern Asia test area(20°-35°N,85°-105°E)for the Global Seismic Hazard Assessment Program(GSHAP).There are significant inhomogeneous and uncompleted data,and n uniformity of earthquake magnitudes in this test area because this region is situated on the boundaries of many countries,such as China,India,Nepal,Vietnam,etc.We establish a relationship between Gutenberg surface-wave magnitude and IASPEI surface-wave magnitude,which can be used for conversion of different magnitude scales into moment magnitude for this catalogue.A catalogue of events with Mw≥6.0 of this test area is given at the end of this paper.     

克里牙北部含油构造的遥感解译

根据油气区地物的波谱特征及影像特征分析和信息提取,发现了新疆克里牙北部含油构造。     

基于Rough Set理论的油层识别方法

本文简介了智能信息处理中新出现的Ｒｏｕｇｈ Ｓｅｔ（ＲＳ）理论,讨论了ＲＳ理论进行决策分析的方法,提出了将连续属性离用化的最优化思想,并探讨了ＲＳ理论用于测井数据判别油水层的问题。判别结果表明;本方法具有速度快,易实现,可优选属性等特点,且判别符合油水层的问题,判别结果表明：本方法具有速度快,易实现,可优选属性等特点,且判别符合率优于手工方法与ＢＰ网络方法,具有实用价值。     

混合岩中浅色体的有限迁移及其对变形分解的影响

熔体在地壳和地幔中怎样迁移及其动力学是地质学中的一个重要问题。作为地壳深融作用的产物 ,混合岩中的浅色体提供了一个极好的机会来探讨影响地壳熔体在中下地壳迁移的因素。为此 ,我们对美国加州南 Sierra Nevada岩基中典型的混合岩、变泥质岩及邻近的花岗闪长岩进行了详细的主要元素地球化学和野外构造变形分析 ,同时应用流体动力学理论估算了在中下地壳条件下 ,典型浅色体的迁移距离。南 Sierra Nevada岩基中的混合岩中的浅色体厚度为 1mm至 1cm。在部分熔融程度较高的区域 (>10 % ) ,浅色体相互连接而成网结状构造 ,应变的承载方式主要以 IWL(Interconnected Weak L ayers)形式进行 ,即熔融体表现为弱相而承载大部分的应变。相反地 ,在部分熔融程度较低的区域 (<5 % ) ,浅色体孤立地出现 ,应变的承载方式主要以 L BF(L oad- Bearing Frame-work)形式进行 ,即应变主要由非熔融体的基质来承担。这表明在混合岩形成过程中 ,熔体的出现强烈地制约着应变分解作用。应用 Shaw的岩石粘度模型 ,我们根据浅色体的主要元素地球化学成分计算了浅色体在熔融状态下的粘度。根据流体动力学原理 ,估算了浅色体在不同条件下的迁移距离。计算结果表明 :1和典型花岗岩相比 ,浅色体具有较高的粘度 ,为 10 9～ 10 1 2     

库车再生前陆盆地油气运移特征

本文首先在数值模拟的基础上对库车再生前陆盆地中主要烃源岩的排烃特征进行了研究。结果表明 ,侏罗系湖沼相泥岩和煤岩是盆地主要的气源岩 ,三叠系湖相泥岩是盆地主要的油源岩 ,克依构造带是盆地主要的烃源区。在此基础上进一步结合构造、地层压力和油气分布等资料对盆地的油气运移特征进行了系统地分析和总结 ,认为库车盆地的油气运移通道主要有两种 ,即断层、不整合面和砂体。断层是油气垂向运移的主要通道 ,位于盆地北部的克依构造带 ;不整合面和砂体是油气侧向运移的主要通道 ,主要与盆地南部秋里塔格构造带和塔北隆起上的油气有关。不同类型的源岩具有不同的排烃时间和油气运移时间。运移动力主要为异常孔隙流体压力 ,垂向运移距离在 2～ 5 km之间 ,侧向运移距离较长 ,一般在 2 0～ 4 0 km之上 ,并以前者为主     

The movement age of hidden fault and analysis on width of its effect zone from shallow seismic sounding and drilling data

Introduction Artificial seismic sounding is a geophysical exploration technique developed in prospectingfor oil and gas and other mineral resources and consists of reflection wave and refraction waveexploration methods. With rapid development of computer techniques and sounding instruments,the reflection wave method became a high-resolution imagery technique for underground struc-tures and is widespreadly used in detection of underground caves and in engineering exploration.In previous se…     

The record of paleoclimatic change from stalagmites and the determination of termination Ⅱ in the south of Guizhou Province,China

A high-resolution climate record from 163.00 kaBP to 113.80 kaBP has been obtained through TIMS-U series dating and carbon and oxygen isotope analysis of the three large stalagmites from two caves in the south of Guizhou Province, China. The record of the oxygen isotopes from the stalagmites reveals that the undulation characteristics between the cooling event of the glacial period and the warming event of the interglacial period in the research area can compare well to those of ice cores, lake sediments, loess and deep sea sediments on the scale of ten-thousand years or millennium time scale. The climate undulation provided by the record of the stalagmites has a coherence with the global changes and a tele-connection to the paleoclimate changes in the north polar region. Our results suggest that the direct dynamics of paleo-monsoon circulation changes reflected in the record of the stalagmites might be caused by changes of the global ice volume, and in turn related to various factors, including the sol     

台湾地区地震的空间关联维特征与构造环境研究

采用关联维方法对台湾地区地震活动的空间特征进行了研究。先利用 10 0a来台湾的地震目录计算各个地震区、带的关联维数 ,将地震空间分布的分形特征定量表达出来 ,然后综合分析地震空间分布的关联维数和孕震构造环境之间的关系 ,得出了以下结论 :1)台湾东、西部地震区由于地震属于不同的大地构造单元 ,因此关联维数有较大的差异 ;2 )在各地震区内部的各个地震带由于板块构造、地壳结构、活断层分布上的差异 ,而具有与其构造特征相对应的关联维数 ;3)各地震带内部的各个不同的部位又由于不同的构造应力场 ,而导致地震分布上出现不同的丛集性 ,表现为不同的关联维数。这些结论充分说明通过关联维分析所得到的地震活动的空间图像与地震活动所代表的不同地质构造背景有着良好的对应关系