华南晚中生代大陆变形、深部过程及动力学

受控古太平洋板块俯冲及后撤作用,华南晚中生代经历了强烈大陆再造,并伴随幕式岩浆活动,是研究活动大陆边缘构造- 岩浆作用、壳幔过程和板块俯冲动力学的天然实验室。本文系统综述了近年来发表的构造变形、岩浆作用和深部结构等多学科成果,以构造解析为主线,深- 浅结合,在华南识别出与古太平洋板块俯冲相关的中晚侏罗世弧背缩短和白垩纪弧后伸展系统,厘定了二者的时空格架和叠加改造关系。弧背缩短系统以扬子中部的隔档- 隔槽式褶皱、深部多层滑脱和双重逆冲推覆构造为特征,具SE向NW的逆冲扩展变形规律,与古太平洋板块的前进式俯冲有关。白垩纪主体以大陆伸展为主,经历了伸展和挤压变形交替,并伴随着岩浆活动的爆发、迁移和停止,其可能与板片俯冲动力学变化有关。在此基础上,我们分析了白垩纪岩石圈长距离伸展的深部过程及浅表响应,提出了岩石圈随深度变化的分层差异伸展模式。自下而上,从岩石圈地幔到上地壳,应变近一致地表现为(W)NW- (E)SE伸展,反映了垂向变形一致性。可能的垂向应力传播过程：板片后撤诱发长距离地幔流,其在岩石圈底部形成剪切牵引应力,促进下岩石圈地幔被动拉伸;上岩石圈地幔局部发育强应变剪切带,作为应力传播构造,其可有效加强壳- 幔间剪切,促进下地壳韧性拉伸,将下地壳和岩石圈地幔的变形关联。我们认为岩石圈伸展、板片后撤和地幔流形成了三位一体的动力学耦合系统,将华南岩石圈长距离伸展的驱动力归结为：① 古太平洋俯冲带海沟后撤和板片回卷诱发的远程效应,和② 地幔流在岩石圈底部施加的剪切牵引应力。     

Stream temperature,specific conductance and runoff process in mountain watersheds

Stream temperature ranged from 3 to 4°C at an experimental site during snowmelt on Hokkaido Island, Japan, which provided direct evidence of major contributions of subsurface water to stream water. In contrast, stream temperatures during rainstorms in summer decreased gradually after stream flow peaked, attaining a nearly constant temperature ranging from 9 to 11°C. During storm flow recession, stream temperatures during summer or snowmelt were similar to the soil temperature at 1·8 m below the land surface, suggesting that subsurface water contributions to stream flow are derived from this depth. The hygrographs during two rainstorms, August 1987 and September 1989, were separated using temperature. The stream temperature was assumed to depend on the mixing of surface flow, having a temperature ranging from that of rainfall to that of shallow (50 cm deep) soil water, and subsurface flow, having the temperature of the soil at 1·8 m below the land surface. Subsurface flow was estimated to contribute 85–90% of the total stream flow during each rainstorm. A two‐component hydrograph separation was also evaluated using specific conductance. Runoff contributions from the two sources for the temperature and specific conductance analysis were similar. Analysis of the temperature and conductance–discharge hysteresis loop, and of individual flow components for storm hygrographs, provide a general picture of the runoff process in the experimental basin. Copyright © 1999 John Wiley & Sons, Ltd.     

雅鲁藏布江流域水文分区研究

青藏高原水系众多,水文站点稀疏,观测资料匮乏,通过水文分区可以将相似流域归为一类,实现其有限测站水文资料向无资料区移用以及达到站网优化设置的目标。以雅鲁藏布江流域(以下简称雅江)为研究对象,利用气象资料和反映下垫面条件的土地利用和地形等物理因子,采用主成分分析、K-Means聚类分析等方法对雅江进行水文分区研究。研究中,根据气候和地形的垂直特征,将雅江划分为5个水文分区,分别为高寒荒漠区、高原温带河谷区、高原峡谷稀林区、高原冰川雨雪区和亚热带山地多雨区,并阐述了各分区的特征。最后,采用斯米尔诺夫检验的方法,选取具有长序列水文资料的站点进行检验,论证了分区结果的合理性。此项成果可为雅江无资料流域水文预测提供依据。     

Cretaceous granitoids and their zircon U–Pb ages across the south‐central part of the Abukuma Highland,Japan

Zircons separated from Cretaceous granitoids are dated from a south‐central transect of the Abukuma metamorphic and granitic terrane. The zircon ages do not follow ‘older’ and ‘younger’ granitoid ages that are used conventionally. In the western part of the study area (Zones I, II and III) where the Takanuki and Gosaisho metamorphic rocks are exposed, the Iritono quartz dioritic stock intruding the greenschist facies rocks in Zone III exhibits the oldest age of 121 Ma in the studied region. Quartz diorite located northward shows 112 Ma, but the other four granitoids intruding into the Takanuki and Gosaisho metamorphic rocks are younger and 103–99 Ma. Two‐mica and biotite granites belong to the youngest age group of 99 Ma. The granitic activities of both the Abukuma and Ryoke belts were initiated by intrusion of quartz dioritic magmas and were ended by two‐mica granite activity. The ages of the eastern two batholiths vary from 110 to 106 Ma (four samples), and show no age common to the Kitakami granitoids farther to the north. Throughout the Japanese Islands arc, Cretaceous granitic activities became younger toward the marginal sea side from the Kitakami Mountains, to the Abukuma Highland, and the Ryoke Belt, then to the Sanin belt of the Inner Zone of Southwest Japan.     

全球海洋大气柱水汽含量遥感融合数据产品生成

本研究利用国际在轨SSMIS、WindSat、AMSR-E、ASMR2和国产HY-2A微波辐射计多源遥感大气柱水汽含量观测数据,基于最优插值算法,生成了2003-2015年全球海洋每日0.25°高分辨率的大气柱水汽含量多源遥感融合产品,以及2012-2015年未使用HY-2A微波辐射计数据的全球海洋每日0.25°遥感融合产品。利用无线电探空仪水汽含量观测数据,对生成的全球海洋大气柱水汽含量融合产品进行精度检验。结果表明,总体上,13年间均方根误差和标准差小于3 mm,平均偏差小于0.6 mm,平均绝对偏差小于2 mm,相关系数大于0.98;使用HY-2A微波辐射计数据产品会使融合结果的精度出现微小的降低;AMSR2和HY-2A微波辐射计数据的联合使用对于替代AMSR-E数据具有积极意义。     

江西弋阳晚白垩世塘边组风成砂岩碎屑锆石U-Pb定年及其物源意义

赣东北信江盆地晚白垩世圭峰群塘边组以发育大型高角度交错层理的风成砂岩为特征,总体为干旱气候条件下沙漠沉积环境的产物。该地区所采砂岩样品为紫红色中-细粒长石石英砂岩,碎屑颗粒主要包括石英、长石、云母和岩屑,多呈次圆状,分选性较好。利用碎屑锆石LA-ICP-MS测年法,对塘边组风成砂岩进行U-Pb同位素定年,分析物源。碎屑锆石颗粒大多数大于100μm,Th/U值为0.1～2.1,且大部分锆石内部具有清晰的振荡环带结构,表明多数为岩浆锆石。~(206)Pb/~(238)U年龄加权平均值为141.4±1.2Ma。锆石U-Pb年龄主要集中于5个年龄段,分别是137～170Ma、431～506Ma、798～1172Ma、1268～2493Ma、2501～3488Ma。这些主要年龄区间与中国东南地区已知的岩浆事件对应,分别为燕山运动、加里东运动、晋宁运动、吕梁运动。其中,燕山期酸性火山-侵入杂岩提供了主要物源。结合风成砂岩交错层理反映的古风向数据,认为弋阳塘边组碎屑物质主要来自盆地北西部的九岭地区及北东部地区。     

Water Resource Development in the Quaternary Ryukyu Limestone Regions of Japan:Application of the GIS to the Site Selection of Underground Dams

Based on the natural and social conditions as well as hydrogeological characteristics of the Ryukyu limestone, a major aquifer in the Ryukyu Islands, a conception of underground dam, was proposed in the early 1970s in order to develop ground water resources in the Quaternary Ryukyu limestone regions of Japan. The practice of nearly thirty years has shown that the underground dam is an environment-friendly and effective way for developing ground water in these regions.To further improve the technology associated with underground dam, the authors introduced related analytic methods. The application of the geographical information system technology to site selection of the underground dam is reported in this paper.     

Petrogenesis of lunar meteorite EET 96008

Lunar meteorite EET 96008 is a fragmental breccia that predominantly consists of basaltic mineral clasts (0.5-2 mm), along with minor lithic fragments and breccia clasts. The matrix consists mainly of smaller mineral fragments (<0.5 mm), bound by glassy cement, the majority of which are pyroxene and plagioclase. The pyroxene possesses extensive exsolution lamellae. These lamellae, up to 1 μm in width, are atypical for mare-basalts. One of the distinguishing textures of EET 96008 is the presence of small pockets (∼400 × 500 μm) of mesostasis areas consisting of coarse (∼20 μm) intergrowths of ferroaugite, fayalite and Si-rich glass. Laths of ilmenite, armalcolite, apatite and whitlockite are also distributed in these areas. Ilmenite grains are abundant and dispersed throughout the thin sections. Chromite and ulvöspinel are present but in minor abundance. Troilite, generally rare in this rock, occurs as several grains in one pyroxene crystal. FeNi metal is conspicuously absent from this meteorite.The molar Fe/Mn ratio in olivines and pyroxenes and the age of the meteorite are evidence for a lunar origin. The mineralogy of EET 96008 shows close affinity to a mare-basalt source, albeit with possible minor highland/non-mare components. The bulk-rock, major-, trace- and rare-earth-element (REE) contents are similar to that of very low-titanium (VLT) basalts, which have experienced extreme fractional crystallization to the point of silicate liquid immiscibility. Mineralogical and textural features of this sample suggest that at least some of the breccia components were derived from a slow-cooled magma. The mineralogy and petrology of EET 96008 is strikingly similar to the lunar meteorite EET 87521, and we support the conclusion that EET 96008 and EET 87521 should be paired.Isochron ages of 3530 ± 270 Ma for apatite and 3519 ± 100 Ma for whitlockite of this rock are consistent with derivation from a mare-basalt precursor. These ages are within error of the low-Ti basalts, dated from the Apollo 12 and 15 sites. The whole-rock, platinum-group-element (PGE) contents of EET 96008 overlap with pristine low-Ti mare basalts, suggesting the presence of only a minimal extraterrestrial component.     

LGZ系列全液压多功能桩机及其在多种工法的应用

LGZ系列全液压多功能桩机拥有可轴向滑移主动钻杆、大扭矩中空式回转动力头和双筒同步卷扬机3项专利技术,具有施工安全、一机多能、传动平稳高效等技术优势。本文介绍了该系列桩机的性能参数、技术特点,及其在螺杆桩、螺旋挤土桩、水泥土搅拌桩、长螺旋钻孔灌注桩、大直径长螺旋钻孔桩等5种工法中的应用。实践证明,LGZ系列全液压多功能桩机可以满足多种桩基工法施工需求,并可扩展到更多工法应用。