具有0.4Ma准周期的事件群发性与气候—构造旋回刍论：—以黄土区为对比区

实地考察研究了中国黄土分布区及其它地区上新世末期以来的各种地质事件，用多种测年法和古土壤断代法确定了黄土、水系、沉积、侵蚀、火山、断裂等气候和构造事件的发生年代，指出第四纪事件具有一种准周期为０．４Ｍａ的同步群发性，提出了一种描述地球内外地质动力全球性变化的“气候－构造旋回”模式。     

论中国黄土的基本地质问题

中国黄土的地质问题,包含的内容十分广泛。本文仅就中国的黄土成因、中国黄土高原形成的地质背景与古环境演化、中国黄土区域地层等基本地质问题加以论述,并着重论述和研究了中国黄土区域地层问题。我们从岩石地层、生物地层、磁性地层、气候地层和年代地层等方面进行了分析对比。对中国黄土地层形成发育有了新的认识。     

地球构造变动对土壤分带格局和古气候事件的影响

本文初步综编了新生代地质事件序列表(以中国为主),其中有一些对应较好的事件群,启发了我们对一些事件时间链的机理思考,并展示了探索气候事件应予涉及的研究范畴。本文通过对全球土壤带分布和全球构造板条分布的对比研究,认为土壤带的分布有两点突出表现：一是与全球构造板条分带格局基本相似,二是喜马拉雅一阿尔卑斯高原山带和美洲科迪勒拉高山高原带决定了两条平行于它们的土壤带,说明构造活动所造成的地形起伏对气候局域变化的重要影响。通过对青藏高原第四纪抬升史及中国黄土－古气候的研究,可以认为,第四纪时期的几次重要的气候转型事件都是由当时的地球构造活动所引发的。     

新构造活化与气候恶化

中国南、北方大陆河流阶地形成初期强烈的侵蚀活动与构造活化、火山喷发、巨厚层黄土发育、冰川扩展等构造、气候事件近于同时，其他大陆上也有类似现象。据此提出了新构造活化在在伴有气候恶化(一般为变冷)以及地球星体运动存在一种具有０．４Ｍａ准周期的气候－构造旋回的概念，并指出自上新世末期以来存在八个主旋回。     

青海省西宁市大墩岭黄土剖面元素组分变化与四纪古气候演化

根据黄土剖面中古土壤系列与砂质黄土中常量元素氧化物含量基本特征，主要地质特征、黄土堆积与古土壤形成古气候环境、演化过程与主要元素组分特征、关系进行了讨论，结合孢粉测年等资料，1.19MaB.P.黄土形成以来的气候演变过程与元素组分变化关系。     

最后两个冰期黄土中记录的Heinrich型气候节拍

洛川、宜川及渭南黄土剖面古风化强度的研究揭示出，在Ｌ１和Ｌ２中记录了一系列干冷气候事件。它们多数发生于黄土与古土壤的交界处，以５０００—１００００ａ的间隔叠置于明显的准２００００ａ岁差周期上。前六个事件的时代与北大西洋的Ｈｅｉｎｒｉｃｈ事件大致相当。上述结果表明，Ｈｅｉｎｒｉｃｈ事件在东亚季风区有明显印迹，且类似事件在相当于深海氧同位素阶段６的黄土中也存在。最后两个事件时我国的古环境状况可能比末次盛冰期还要干冷些。这些事件出现的地层层位似乎表明，它们易发生于由地球轨道变化引起的气候转变时期。     

后记之一

有关黄土是由大量的降尘物质堆积演化而成的看法，即通常所说的“风成学说”，已被愈来愈多的第四纪科学家所接受。近年来，有的学者提出了我国北方黄土层以下的红粘土的原始物质源自降尘的看法。黄土区以及大部分由黄土物质重新堆积形成的华北平原是中华文明的摇篮，如果地质时期没有大量的粉尘堆积并继而形成有利于农业耕作的广袤的黄土区，那么中华文明的发展大概又该是另外一种模式了。从这个角度看，沙尘及由它导致的粉尘堆积并不是毫无积极意义的地质事件。不过，到了人类文明高度发展的今天，沙尘事件却愈来愈成为困扰人们的日常生产…     

新疆伊犁盆地黄土古气候记录与Heinrich事件对比分析

伊犁盆地作为中国黄土高原与欧洲黄土区的过渡区域,其第四纪古气候研究对于揭示全球气候驱动及耦合机制具有重要的意义.通过对伊犁盆地塔勒德晚更新世黄土-古土壤剖面粒度、低频磁化率及地球化学元素分析,探讨了西风区黄土-古土壤序列中古气候指标变化特征及记录的全球气候突变事件.结果表明:古土壤层中粒径10μm颗粒物含量明显高于黄土层,与之相反的是古土壤层中的低频磁化率、Zr/Rb值和元素Ti含量均小于黄土层,且元素Ti含量与Zr/Rb间具有较高的相关性.黄土-古土壤剖面中古气候代用指标清晰的记录了6次Heinrich(H)事件及Younger Drays(YD)事件,但YD事件、H1、H2、H5和H6事件变幅较H3和H4事件显著,古气候指标与格陵兰冰芯δ18O、季风区李家塬粒度和洛川、西峰及环县Zr/Rb值均具有较好的一致性,所记录的气候事件较李家塬、洛川、西峰更为显著.结合已有研究说明,Heinrich和D-O旋回等气候事件是由西风区向季风区传递的,MIS3阶段温度的升高和常年受西风的影响是造成塔勒德气候环境变化特征的主要控制因素.     

中亚黄土沉积与西风区末次冰期快速气候变化

气候快速变化过程与机制一直是古气候研究的热点科学问题,随着不同地区高分辨率地质记录的增多,年代学方法的改进,此类快速气候变化事件的区域差异性日益突出,对比和认识这些区域之间的变化细节,有助于认识快速气候变化的规律和驱动机制。文章以中亚黄土为主要研究对象,根据黄土沉积特征与现代气候特征,将中亚黄土分为西部、北部和东部3个亚区,在总结中亚西风区黄土古气候研究进展的基础上,回顾了近年来中亚地区末次冰期西风区气候突变事件研究现状与问题,初步探讨了在亚轨道尺度上末次冰期快速气候变化发生过程和机制。结果表明,粒度、矿物学、地球化学等指标均指示中亚这3个黄土亚区末次冰期确实存在千年尺度的快速气候波动信号,但在年代和变率上存在区域差异,这种差异除了缺乏精确的年代学控制外,还与区域水热组合和区域地形结构有关。这些冷暖的快速气候变化与北大西洋高纬地区冰盖收缩扩张、西伯利亚高压强度和范围的变化导致风动力变化和西风带南北迁移有关。今后需进一步加强高分辨率年代序列的建立,进一步遴选中亚黄土中有效的、能够独立反映风力强度、源区信息、古温度、古降水等代用指标,并结合古气候模拟试验研究其驱动机制。     

多重地层方法在第四系1∶5万区调中的应用

结合河北矾山幅(Ｋ－５０－１３５－Ｂ）１∶５万区调成果，在全面分析了第四纪地层常用划分方法（岩性法、地貌法、古生物法、气候法、古地磁法、年龄法）的利弊和应用效果的基础上，提出对第四系进行多重地层综合划分应分三步：①根据岩石地层学和地貌地层方法，建立研究区地层相对新老顺序；②根据生物地层学、气候地层学等方法，确定地层的相对地质年代；③根据古地磁和年代学方法，确定重要地质界限和地质事件的年龄；并对多重地层方法野外填图的基本程序进行了讨论。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

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GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)     

GEOCHEMISTRY

正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861