冲断层、张性断层与花岗岩侵入作用关系的构造证据

本文提出了翁布里诺（Hombreiro）侵入体新的构造和岩石组构资料。翁布里诺侵入体是位于西班牙华力西构造带北部的一个同构造便位的花岗岩体。该岩体表现有两期塑性交形特征:早期变形与蒙多涅多（Mondonedo）推覆体的运动有关,此推覆体具有上盘向东的剪切指向;晚期变形则与比韦罗（Vivero）断层有关,此断层为一上盘向西运动的张性剪切带。这两期变形都始于高温近花岗岩固相线条件下,石英中保留有[c]-滑移组构可作证明。这一事实表明,在蒙多涅多推覆体上冲过程中,翁布里诺花岗岩发生侵位,在其定位过程中,张性断层不久即开始活动。本文提出,比韦罗断层的位置受地壳不稳定性所控制,而这种地壳不稳定性则由位于该断层下盘的许多侵入体的侵入作用所引起。     

深反射地震揭示喜马拉雅地区地壳上地幔的复杂结构

报告了中、美两国在喜马拉雅山区进行的第一次深反射地震试验的结果．试验剖面南起喜马拉雅山山脊南亚东县的帕里镇,向北穿过喜马拉雅山脊的荡拉,到达康马南的萨马达．剖面长约１００ｋｍ．共中心点（ＣＭＰ）叠加剖面上显示出：１．在地壳中部有一强反射带,向北缓倾斜下去,延长达１００ｋｍ以上．它可能代表了一个活动的逆冲断裂或是一条巨大的拆离带,印度地壳整体或下地壳沿此拆离层俯冲到藏南之下．２．上部地壳的反射很丰富,显示了上地壳存在着大规模的叠瓦状结构．３．下地壳的反射同相轴呈现短而有规律的分布,显示了塑性流变特征．４．在测线南部莫霍反射明显,深度达７２－７５ｋｍ．发现南部有双莫霍层的存在．５．试验中还取得莫霍层下面３２,３８,４８ｓ等双程走时的多条反射,向北倾斜,反射同相轴延续较长,信息丰富,反映了上地幔的成层结构和变形特征．这些结果对印度大陆地壳整体或其下地壳俯冲到藏南特提斯喜马拉雅地壳之下,并导致西藏南端地壳增厚的观点,给予了实质性的支持．     

雅鲁藏布江缝合带的双陆内俯冲构造与部分熔融层特征──INDEPTH项目结果的初步综合

根据中、美两国合作开展的西藏深反射地震结果,提出雅鲁藏布江缝合带（YZS）的"双陆内俯冲"构造模式和缝合带南、北分别存在着不同特征的、规模不一的部分熔融层;提出YZS处断裂向深部延深有限,认为YZS处地壳增厚有4种机制：①地壳规模的大的俯冲增厚;②上部地壳内的俯冲和背冲增厚;③下地壳内的底部垫托增厚和挤压增厚;④深部熔融体的向上挤入而引起的地壳增厚.提出可能存在两条大的伸展性断裂,造成江孜南、北地块间出现了大升降.     

长江中游反向过程——来自四川盆地东部的构造地貌指示

万里长江的形成经历了数次大规模的河流袭夺事件,现今的长江中游河段(川江)曾经作为古长江的西支,自东向西汇入南流的古金沙江,后来由于不断的反向才使其与古长江的东支,即现今的长江下游得以贯通。针对这一河流演化模式,学术界普遍将长江三峡的黄陵背斜视为古长江东支和西支的分水岭,然而却一直未能获得有效的地貌证据,以致于无法解释具体的河流袭夺和反向过程。为此,本文从川东-湘鄂西弧形断褶带的构造地貌特征入手,深入分析了不同区段长江及其支流与构造线的交切关系,提出古长江东支和西支的分水岭应位于弧形带的"中线"附近的向斜谷地内,而并非前人认为的黄陵背斜。通过对向斜谷地内正交型水系样式下的河流袭夺案例分析,结合先进的河流纵剖面分析技术,揭示出由于基准面下降而造成的纵向河段被袭夺并最终反向的机制。另外,根据江汉盆地西缘(宜昌地区)的白垩纪-新生代地层的沉积学和物源分析,进一步限定了长江中游的袭夺和反向开始于始新世,直到中新世才形成现今贯通的长江。     

结合某滑坡浅谈人类活动对地质环境的影响

文章通过某滑坡的现场调查、勘探取样及综合分析计算,着重说明了人类活动对滑坡体的稳定性影响,以及工程建设中保护生态与地质环境的重要性。     

Identification of Milankovitch Cycles and Calculation of Net Primary Productivity of Paleo-peatlands using Geophysical Logs of Coal Seams

Individual coal seams formed in paleo-peatlands represent sustained periods of terrestrial carbon accumulation and a key environmental indicator attributed to this record is the rate of carbon accumulation. Determining the rate of carbon accumulation requires a measure of time contained within the coal. This study aimed to determine this rate via the identification of Milankovitch orbital cycles in the coals. The geophysical log is an ideal paleoclimate proxy and has been widely used in the study of sedimentary records using spectral analysis. Spectral analyses of geophysical log from thick coal seams can be used to identify the Milankovitch cycles and to calculate the period of the coal deposition. By considering the carbon loss during coalification, the long-term average carbon accumulation rate and net primary productivity (NPP) of paleo-peatlands in coal seams can be obtained. This review paper presents the procedures of analysis, assessment of results and interpretation of geophysical logs in determining the NPP of paleo-peatlands.     

花岗质岩浆产生和演化过程中水的作用与来源

温度和含水量是形成花岗质岩浆最重要的两个参数。在大多数硅质岩浆中，水的含量为2－4wt%。水的主要来源有二，其一是地壳内含水硅酸盐的脱水作用，并视脱水矿物为白云平、黑云母或角闪石，所产生熔体的初始温度相应依次升高，成分由过铝质到偏铝质变为偏铝质到过碱质，K／Na比值、^87Sr/^86Sr初始比值和δ^18O值则依次降低。水的另一主要来源是由俯冲洋壳及上地幔（以含水玄武岩和安山岩的形式)迁移到地壳中的挥发分，所产生花岗岩的地球化学性质将随地壳岩浆与地幔岩浆的相对重要性而变化。     

Dextral‐Slip Thrust Faulting and Seismic Events of the Ms 8.0 Wenchuan Earthquake,Longmenshan Mountains,Eastern Margin of the Tibetan Plateau

Abstract: Dextral-slip thrust movement of the Songpan-Garzê terrain over the Sichuan block caused the Ms 8.0 Wenchuan earthquake of May 12, 2008 and offset the Central Longmenshan Fault (CLF) along a distance of ~250 km. Displacement along the CLF changes from Yingxiu to Qingchuan. The total oblique slip of up to 7.6 m in Yingxiu near the epicenter of the earthquake, decreases northeastward to 5.3 m, 6.6 m, 4.4 m, 2.5 m and 1.1 m in Hongkou, Beichuan, Pingtong, Nanba and Qingchuan, respectively. This offset apparently occurred during a sequence of four reported seismic events, EQ1–EQ4, which were identified by seismic inversion of the source mechanism. These events occurred in rapid succession as the fault break propagated northeastward during the earthquake. Variations in the plunge of slickensides along the CLF appear to match these events. The Mw 7.5 EQ1 event occurred during the first 0–10 s along the Yingxiu-Hongkou section of the CLF and is characterized by 1.7 m vertical slip and vertical slickensides. The Mw 8.0 EQ2 event, which occurred during the next 10–42 s along the Yingxiu-Yanziyan section of the CLF, is marked by major dextral-slip with minor thrust and slickensides plunging 25°–35° southwestward. The Mw 7.5 EQ3 event occurred during the following 42–60 s and resulted in dextral-slip and slickensides plunging 10° southwestward in Beichuan and plunging 73° southwestward in Hongkou. The Mw 7.7 EQ4 event, which occurred during the final 60–95 s along the Beichuan-Qingchuan section of the CLF, is characterized by nearly equal values of dextral and vertical slips with slickensides plunging 45°–50° southwestward. These seismic events match and evidently controlled the concentrations of landslide dams caused by the Wenchuan earthquake in Longmenshan Mountains.     

黄淮海旱区喜降雨雪南方上中旬阴雨寡照—1997年2月—

黄淮海旱区喜降雨雪南方上中旬阴雨寡照—１９９７年２月—陆均天王平（国家气候中心，北京１０００８１）２月，影响我国的冷空气强度弱，全国大部地区气温较常年同期偏高。上中旬，北方大部降水偏少，华北中南部和黄淮等地区干旱明显，下旬一场大范围的降水天气，使旱情...     

The mean value concept in mono-linear regression of multi-variables and its application to trace studies in geosciences

The "mean value concept" in a mono-linear regression of multi-variables is clarified.Its applications to reconstruction of the past 90-year salinity of the sea surface water in Xisha Islands and to tracing the past 80 ka paleo-geomagnetic events from the Luochuan loess 10Be record are introduced in detail,which show the significance and the potential of the "mean value concept" in geoscience research.