Late Oligocene-Early Miocene Thrusting in Southern East Kunlun Mountains, Northern Tibetan Plateau

Southward thrusting occurred in Late Oligocene-Early Miocene in southern East Kunlun (昆仑) Mountains formed the South Kunlun thrust (SKT). Permian strata and Triassic rocks were thrusted over the Paleocene-Eocene red-beds of Fenghuoshan (风火山) Group and Oligocene brownish red conglomerate and sandstone of Yaxicuo (雅西错) Group along SKT faults, formed tectonic slices, low-angle thrust faults, multi-scaled outliers, and nappe structures in south of Middle Kunlun fault (MKF). In addition, SKT displacement or shortening is estimated to be ～(30-35) km across Dongdatan (东大滩) valley and East Wenquan (温泉) basin. 39Ar-40Ar dating of chlorite of ductile shear zone along front thrust fault indicates that SKT thrusting occurred at 26.5±2.7 Ma, and fission track dating of apatite from mylonitic granite in SKT gives the age 26±2 Ma, corresponding to initial time of rapid uplift of East Kunlun Mountains. Thrust faults and folds of SKT were covered unconformably by Late Miocene lacustrine strata, and major thrusting of SKT ended before 13.5-14.5 Ma according to regional chronological data in northern Tibetan plateau.     

川西攀枝花—西昌地区结晶基底的划分

长期以来,由于同位素年龄依据不足和没有正确区分晚二叠世热接触变质岩、喜马拉雅期动力变质岩与前震旦纪区域变质岩,攀西地区结晶基底的划分存在许多困难和问题。本文依据1：50000区域地质调查结果,将原仁和群(Pt1R)修改为晚二叠世岩浆岩和喜马拉雅期动力变质岩,将五马箐(岩)组(Pt1w)和顶针杂岩(Pt1D)修改为晚二叠世热接触变质岩和喜马拉雅期动力变质岩,将安宁村组(Ptlα)和纸房沟组(Pt1z)修改为震旦系地层,并依据岩石学、岩石化学和微量元素地球化学特征,将结晶基底划分为变质侵入体、变质表壳岩和TTG套岩,论述了结晶基底的成因和演化。     

Sunspot numbers based on historic records in the 1610s: Early telescopic observations by Simon Marius and others

Hoyt & Schatten (1998) claim that Simon Marius would have observed the sun from 1617 Jun 7 to 1618 Dec 31 (Gregorian calendar) all days, except three short gaps in 1618, but would never have detected a sunspot – based on a quotation from Marius in Wolf (1857), but mis‐interpreted by Hoyt & Schatten. Marius himself specified in early 1619 that for one and a half year... rather few or more often no spots could be detected... which was never observed before (Marius 1619). The generic statement by Marius can be interpreted such that the active day fraction was below 0.5 (but not zero) from fall 1617 to spring 1619 and that it was 1 before fall 1617 (since August 1611). Hoyt & Schatten cite Zinner (1952), who referred to Zinner (1942), where observing dates by Marius since 1611 are given but which were not used by Hoyt & Schatten. We present all relevant texts from Marius where he clearly stated that he observed many spots in different form on and since 1611 Aug 3 (Julian) = Aug 13 (Greg.) (on the first day together with Ahasverus Schmidnerus); 14 spots on 1612 May 30 (Julian) = Jun 9 (Greg.), which is consistent with drawings by Galilei and Jungius for that day, the latter is shown here for the first time; at least one spot on 1611 Oct 3 and/or 11 (Julian), i.e. Oct 13 and/or 21 (Greg.), when he changed his sunspot observing technique; he also mentioned that he has drawn sunspots for 1611 Nov 17 (Julian) = Nov 27 (Greg.); in addition to those clearly datable detections, there is evidence in the texts for regular observations. For all the information that can be compared to other observers, the data from Marius could be confirmed, so that his texts are highly credible. We also correct several shortcomings or apparent errors in the database by Hoyt & Schatten (1998) regarding 1612 (Harriot), 1615 (Saxonius, Tard´e), 1616 (Tard´e), 1617–1619 (Marius, Riccioli/Argoli), and Malapert (for 1618, 1620, and 1621). Furthermore, Schmidnerus, Cysat, David & Johann Fabricius, Tanner, Perovius, Argoli, and Wely are not mentioned as observers for 1611, 1612, 1618, 1620, and 1621 in Hoyt & Schatten. Marius and Schmidnerus are among the earliest datable telescopic sunspot observers (1611 Aug 3, Julian), namely after Harriot, the two Fabricius (father and son), Scheiner, and Cysat. Sunspots records by Malapert from 1618 to 1621 show that the last low‐latitude spot was seen in Dec 1620, while the first high‐latitude spots were noticed in June and Oct 1620, so that the Schwabe cycle turnover (minimum) took place around that time, which is also consistent with the sunspot trend mentioned by Marius and with naked‐eye spots and likely true aurorae. We consider discrepancies in the Hoyt & Schatten (1998) systematics, we compile the active day fractions for the 1610s, and we critically discuss very recent publications on Marius which include the following Maunder Minimum. Our work should be seen as a call to go back to the historical sources. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

中国南部及邻区能源资源成矿区带数据集

能源矿产是国家安全和经济发展的战略资源,加强我国及周边地区油气和煤等能源资源的研究和开发利用意义重大。依据板块构造和大陆动力学以及油气与煤成藏地质学理论,以深部构造控制盆—山发育、盆—山耦合和热动力系统控制成矿的研究工作思路,应用70个油气田、471个煤田的基础地质资料,从沉积盆地发育的区域地质特征、成矿地质条件和成矿单元诸多方面,在地理信息系统（GIS）平台上提示了该区板块构造格局与能源资源的时空分布规律。中国南部及邻区能源资源可划分为3个成矿域,每个成矿域又可进一步划分为成矿省、含矿区（盆地）、矿田聚集区带、矿田（油气田）五个级别的成矿区域。数据集由构造带（断裂带和造山带）类型和时代、盆地类型和时代、能源矿产资源类型和丰度、成矿区带等元数据组成。该数据集是在区域大地构造研究的基础上,结合沉积盆地能源矿产（石油、天然气、煤）资源评价资料,综合分析成矿区带特征,利用地理信息系统（GIS）建立的一套完整的数据库,不仅是对中国南部及邻区区域地质认识和沉积盆地能源资源勘查工作成果的集成,而且为国家科学地引导地质找矿工作部署提供理论基础。     

城市化影响地下水水质的正负效应

以石家庄市为例, 通过城市化水平和地下水污染态势的定量计算、分析, 对城市化影响地下水水质的机理及其正负效应进行了探讨.结果表明: 石家庄城市化发展处于初级阶段; 城市化影响地下水水质有正负两方面的效应, 城市化水平的提高, 有助于改善地下水水质, 但却易于加剧地下水盐污染.本研究为以地下水作为主要、甚至唯一供水水源城市的可持续发展提供了一种理论和根本途径.      

Early formed regional antiforms and synforms that fold younger matrix schistosities: their effect on sites of mineral growth

In the metamorphic cores of many orogenic belts, large macroscopic folds in compositional layering also appear to fold one or more pervasive matrix foliations. The latter geometry suggests the folds formed relatively late in the tectonic history, after foliation development. However, microstructural analysis of four examples of such folds suggests this is not the case. The folds formed relatively early in the orogenic history and are the end product of multiple, near orthogonal, overprinting bulk shortening events. Once large macroscopic folds initiate, they may tighten further during successive periods of sub-parallel shortening, folding or reactivation of foliations that develop during intervening periods of near orthogonal shortening. Reactivation of the compositional layering defining the fold limbs causes foliation to be rotated into parallelism with the limbs.Multiple periods of porphyroblast growth accompanied the multiple phases of deformation that postdated the initial development of these folds. Some of these phases of deformation were attended by the development of large numbers of same asymmetry spiral-shaped inclusion trails in porphyroblasts on one limb of the fold and not the other, or larger numbers of opposite asymmetry spirals on the other limb, or similar numbers of the same asymmetry spirals on both limbs. Significantly, the largest disparity in numbers from limb to limb occurred for the first of these cases. For all four regional folds examined, the structural relationships that accompanied these large disparities were identical. In each case the shear sense operating on steeply dipping foliations was opposite to that required to originally develop the fold. Reactivation of the folded compositional layering was not possible for this shear sense. This favoured the development of sites of approximately coaxial shortening early during the deformation history, enhancing microfracture and promoting the growth of porphyroblasts on this limb in comparision to the other. These distributions of inclusion trail geometries from limb to limb cannot be explained by porphyroblast rotation, or folding of pre-existing rotated porphyroblasts within a shear zone, but can be explained by development of the inclusion trails synchronous with successive sub-vertical and sub-horizontal foliations.     

永定河中下游MIS7以来地层沉积演化及新石器时代以来气候变化

利用廊坊东A27钻孔岩心资料,样品微体生物、孢粉特征综合分析,结合AMS14C测年,对永定河中下游地区MIS7以来的地层进行分析,建立了MIS7以来的沉积地层格架,并对其进行了年代厘定,讨论了该地区大约MIS7阶段以来氧同位素分期气候下的地层及环境效应.结果表明,永定河中下游地区晚第四纪可划分为U1～U8共8个沉积单元...     

Stress‐dependent hardening and failure surfaces of dry sand

During several triaxial compression experiments on plastic hardening, softening, and failure properties of dense sand specimens, it was found on various stress paths that the size of the failure surface was not constant. Instead, it changed depending on the current state of hydrostatic pressure. This finding is in contrast to the standard opinion consisting of the fact that the failure surface remains constant, once it has been reached during an experiment or in situ. In general, the behaviour of cohesionless granular‐material‐like sand is somehow characterised in between fluid and solid, where the solid behaviour results from the angle of internal friction and the confining pressure. Although the friction angle is an intrinsic material property, the confining pressure varies with the boundary conditions, thus defining different solid properties like plastic hardening, softening, and also failure. Based on our findings, it was the goal of the present contribution to introduce an improved setting for the plastic strain hardening and softening behaviour including the newly found yield properties at the limit state. For the identification of the material parameters, a complete triaxial experimental analysis of the tested sand is given. The overall elasto‐plasticity concept is validated by numerical computations of several laboratory foundation‐ and slope‐failure experiments. The performance of the proposed approach is compared with the standard concept of a constant failure surface, where the corresponding yield surfaces are understood as contours of equivalent plastic work or plastic strain. Copyright © 2012 John Wiley & Sons, Ltd.     

利用背景噪声反演鄂尔多斯块体及其南缘地区地壳速度结构

文中利用分布在鄂尔多斯块体及其南部周缘地区的53 个宽频带地震固定台站的连续波形记录,采用双台互相关计算 方法由背景噪声提取瑞利波格林函数,经时频分析获得相速度和群速度频散曲线,并分别计算了汾渭地堑、秦岭北缘、鄂 尔多斯块体内部和六盘山地区4 个不同构造区的平均频散曲线,进而反演了各构造区的地壳上地幔一维横波速度结构。结 果显示：地壳厚度在汾渭地堑为34 km,在秦岭北缘地区和鄂尔多斯块体均为40 km,在六盘山地区最厚,达49~50 km;相 应的上地幔顶部横波速度分别为4.20,4.2,4.30 和4.15 km/s;地壳内结构浅部特征差异最大,在地壳中部六盘山地区的速 度较低,下部地壳不同地区的波速较一致。     

河流形态的分维及与洪水关系的探讨--以长江中下游为例

河流水系形态特征可以通过河流的分形特征来反映,分形维数则是河流分形特征的量化表示,其与河流洪水之间存在着一定的关系。以长江中下游为例,利用网格覆盖法计算出长江中下游河流分维,分析了长江中下游河流的分形特性,并在此基础上结合长江中下游洪水分析不同水系特征下洪水的特点。研究结果表明,一般来说河道分维越大、河网分维越小,洪水发生可能性则越高。