江西广丰地区中奥陶统层序地层分析

本文通过对广丰县周家坞中奥陶统露头剖面层序、体系域、副层序的研究，识别出了三个不同性质的Ⅱ型层序界面和二个三级层序，确认这三个层序界面为符合实际又易于野外识别的自然界面，并对ＳＱ２中反映最大海泛期的高分辨异旋回驱动机制事件，提出可能受米兰柯维奇频率的春分点和秋分点间约２万年间隔的控制。     

三维任意形体高密度电阻率法数值模拟方法

为研究高密度电阻率法对各种三维地电体的反映规律，本文介绍了正演程序编制的方法并给出了计算实例。     

Structure of the Mount Raymond transverse zone at the southern end of the Wyoming salient, Sevier fold-thrust belt, Utah

The Mount Raymond transverse zone (MRTZ) forms the east-west-trending boundary between the Wyoming salient of the Sevier fold-thrust belt and the Uinta/Cottonwood arch in north-central Utah. Major faults in the zone dip 40° to 45° north. Our structural analysis indicates that the MRTZ contains both contractional and extensional structures. The contractional structures (thrusts and related folds) initially formed as part of a southeast-verging, northeast-trending thrust system. This system gradually curved and merged to the north with the east-verging Absaroka thrust system in the apex of the Wyoming salient. The contrast in trend between structures in the MRTZ and those in the apex of the Wyoming salient reflects the initial curvature of the salient. This curve formed because the stratigraphic sequence involved in thrusting thinned gradually southward, toward the axis of a proto-Uinta arch. The present east-west trend of the MRTZ developed during Laramide uplift of the Unita/Cottonwood arch, an event which tilted the faults into their present position. Cenozoic crustal extension subsequently reactivated segments of the MRTZ. In sum, the evolution of the MRTZ illustrates how post-thrusting processes can affect the map-view geometry of thrust belts to create transverse zones.     

Accretion and exhumation at a Variscan active margin, recorded in the Saxothuringian flysch

The Saxothuringian flysch basin, on the north flank of the Central European Variscides, was fed and eventually overthrust by the northwestern, active margin of the Tepla-Barrandian terrane. Clast spectra, mineral composition and isotopic ages of detrital mica and zircon have been analyzed in order to constrain accretion and exhumation of rocks in the orogenic wedge. The earliest clastic sediments preserved are of early Famennian age (ca. 370?Ma). They are exposed immediately to the NW of the suture, and belong to the par-autochthon of the foreland. Besides ultramafic (?ophiolite) material, these rocks contain clasts derived from Early Paleozoic continental slope sediments, originally deposited at the NW margin of the Saxothuringian basin. These findings, together with the paleogeographic position of the Famennian clastics debris on the northwestern passive margin, indicate that the Saxothuringian narrow ocean had been closed by that time. Microprobe analyses of detrital hornblendes suggest derivation from the “Randamphibolit” unit, now present in the middle part of the Saxothuringian allochthon (Münchberg nappes). Detrital zircons of metamorphic rocks formed a little earlier (ca. 380?Ma) indicate rapid recycling at the tectonic front. The middle part of the flysch sequence (ca. early to middle Viséan), both in the par-autochthon and in the allochthon, contains abundant clasts of Paleozoic rocks derived from the northwestern slope and rise, together with debris of Cadomian basement, 500-Ma granitoids and 380?Ma (early Variscan) crystalline rocks. All of these source rocks were still available in the youngest part of the flysch (c. middle to late Viséan), but some clasts record, in addition, accretion of the northwestern shelf. Our findings permit deduction of minimum rates of tectonic shortening well in excess of 10–30?mm per year, and rates of exhumation of ca. 3?mm/a, and possibly more.     

Conductivity of NaCl solution at 0.4–5.0 GPa and 25–500 °C

NaCI-H₂O is the most fundamental ternary system in geology. Until now, the measurements of electrical conductivity of NaCl solutions are still little at high pressures (> O.5 GPa) We measured the conductivity of 0.01 m NaCl solution at 0.4–5.0 GPa and 25-500°C. The results are consistent with that of Quist and Marshall (1968) at 0.4 GPa. The conductivity of NaCl solution increases with increasing temperature. The results also show that the conductivity of NaCl solution changes little with increasing pressure below 1.5 GPa and changes rapidly with increasing pressure above 1.5 GPa. The rapid increase of the conductivity of NaCl solution may play an important role in many geological processes (such as the genesis of ore deposits under hydrothermal condition) and other fields. Project supported by the National Natural Science Foundation of China.     

Crustal structure of Dabieshan orogenic belt

The crustal structures ofP velocity and density on the deep seismic sounding profile across the Ilabieshan orogenic belt are presented. There is a 5-km-thick crustal “root” between the Yuexi and Xiaotian where the elevation is highest on the profile. An apparent Moho offset of 4. 5 km beneath the Xiaotian-Mozitan fault marks the paleo-suture of the Triassic collision. A high-velocity anomaly zone at the depth below 3 km beneath the ultra-high pressure (UHP) zone may be correlated to the higher content of UHP metamorphic rocks. Project supported by the National Natural Science Foundation of China and the Joint Earthquake Science Foundation.     

造山带岩浆活动与构造运动关系研究综述

熔体及其活动在造山带的演化中发挥了重要作用。熔体活动发迹了地壳应力作用方式而诱发形成剪切带或断层；熔体活动调整块体间的位移而影响造山带的变形；     

秦岭造山带南北向构造及有关问题的讨论

秦岭造山带具有复杂和长期演化的历史，本文对秦岭造山带的主造山期，结构特征（包括构造单元划分），构造体制和发展演化等进行了综合和讨论。     

滇西北金沙江带蛇绿岩,蛇绿混杂岩形成环境及时代

本文对滇西北金沙江带蛇绿岩及其混杂岩的产状、规模，岩石学及岩石化学特征等进行系统的综合研究，并根据大量的化石资料，将该区蛇绿岩的形成时代厘定为晚石炭世至二叠纪，蛇绿要岩的形成时代厘定为早、中三叠世，论证了本区蛇绿岩产于规模较小的洋盆环境之中，由于金沙江洋盆发育阶段较短暂，不具有隔离冈瓦纳及扬子两大古生物地理区系的作用，因此，金沙江缝合带不能构成古特提斯域的主缝合带。     

Quantitative Tectonic Markers of Large Coastal Earthquakes in Fujian, Guangdong, Taiwan and Hainan——with a Discussion of Qualitative Indicators

This paper expounds the quantitative tectonic indicators and some qualitative indicators of large earthquakes in the coast areas of Fujian, Guangdong, Taiwan and Hainan. The main quantitative indicators include uplift amplitude of the Moho, Quaternary and Late Holocene coasts. The paper also gives a brief account of the research method on quantitative indicators of surface uplifted zones. Taiwan is a famous neotectonic zone and an area of large earthquakes in the world. There is only one large-earthquake area in each of Fujian, Guangdong and Hainan Provinces. Along the coast large earthquake areas there are certainly many remains of crustal activity. Among these remains, coast activity, taking the sea level as the accurate marker horizon, can determine not only the amplitude of coastal elevation and subsidence in a certain period, but also the cycle and rate of positive or negative movements.