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1.
根据岩石地导学与地貌地层学特征,将江西修水地区的第四系列分为5个岩石地层单位。由老到新为:(1)赣县组为一套暗红色强风化砾石层,组成修水河第五级阶地,形成时代大于1.0Ma.B.P;(2)进贤组分上,下两段,下段为棕红色强网纹化红土和砂砾层,组成第四级河流阶地,上段为一套褐红色网纹化亚粘土与砂,砂砾石组合,组成第三级阶地,进贤组成的年龄大致为0.9~0.1MaB.P;(3)莲塘组岩性以厚层的褐黄色  相似文献   

2.
江西修水第四系网纹红土的地层学研究   总被引:32,自引:1,他引:32  
根据大量野外观察和室内分析结果,较详细论述了江西修水地区第四系网纹红土的地貌地层、岩石地层、磁性地层和年代地层等方面的特征,并在此基础上,就有关网纹红土的形成时代、成因以及与黄土的对比等问题进行了讨论,提出1)网纹红土可分为强网纹化红土和弱网纹化红土两个岩性段,每个岩性段又由若干个密集网纹层与稀疏网纹层构成;网纹红土与下伏红色砾石层属同期产物;2)网纹红土中的密集网纹层的地质意义相当于北方黄土中的古土壤;3)网纹红土形成于早更新世末(约0.9MaB.P.)至晚更新世初(约0.1MaB.P.);4)网纹红土发育于湿热气候条件下,地下水埋深浅,地表低洼、排水不畅的环境。  相似文献   

3.
黄河中游水系的阶地发育时代   总被引:62,自引:2,他引:62  
岳乐平  雷祥义 《地质论评》1997,43(2):186-192
本文通过磁性地层学方法研究了兰州段黄河阶地,宝鸡段渭河阶地,洛川段洛河阶地,结果表明:兰州段黄河最高阶为六级阶地,发育于1.40MaB.P.,兰州地区黄河最早出现在1.60MaB.P.。一级支流宝鸡段渭河最高阶地为五级阶地,发育于1.20MaB.P.洛川地区洛阳最早出现在1.20MaB.P.。黄河中游水系的阶地形成,主要是由于青藏高原的隆起以及地壳不断震抬升作用造成的。  相似文献   

4.
一、工区地层情况工区地形属冲积绿洲平原,局部洼沟最大高差2~4m,稍加修整,汽车可以通行。钻孔穿过的地层,有冲积物,洪积物和风积物构成的河漫滩,其间以砂砾石层、砾石层为主,砂土层仅在部分Ⅰ级阶地和Ⅱ级阶地出现100~500mm;砾石有花岗岩、闪长岩、石英岩、花岗片麻岩和脉石英等;砾石度(从浅井中得知)大于100mm的占63%,大于300mm的占23%;从河漫滩观察,磨盘大的砾石,亦是星罗棋布,由此给施工带来困难,打半节孔的机会很多。  相似文献   

5.
一、问题的提出砂金矿床大都是分布在河床、河谷阶地、湖滨等地带,地层多由亚砂土、砂和砂砾石等组成,在砾石层中往往含有大小不等、成份复杂的漂卵砾石,在砂矿钻探中必须穿过这类复杂层位;并钻至基岩一定深度而终孔。其中钻孔要穿过漂、卵石则是一大难关,往往在钻进中被迫停钻,不得不另打新孔,有时一处要打几个才能成孔一个,甚至一个也成不了,其结果不但影响一个矿区的普查勘探速度,增加勘探成本,而且也影响了地质资料的收集和地质报告的质量。所以,在砂矿普查勘探中,对穿过漂、卵砾石问题一直是国内外砂矿钻探工作者不易解决的难题,如  相似文献   

6.
宁夏清水河谷盆地广泛发育全新世冲积层,构成二—三级阶地,主要为一套粉砂质土、亚砂土夹砂砾石层。内含丰富的孢粉计90余属种,自下而上建立3套孢粉组合。经区域对比,其年代地层分别相当于下、中、上全新统。古气候经历了寒冷干燥—温暖偏干—干旱的演变。  相似文献   

7.
宁夏同心县清水河全新世地层   总被引:1,自引:0,他引:1  
宁夏清水河谷盆地广泛发育全新世冲积层,构成二-三级阶地,主要为一套粉砂质土、亚砂土夹砂砾石层。内含丰富的孢粉计90余属种,自下而上建立3套孢粉组合,经区域对比,其年代地层分别相当于下、中、上全新统。古气候经历了寒冷干燥-温暖偏干-干旱的演变。  相似文献   

8.
通过对大兴安岭北段东坡扎兰屯东南前新生代基岩上高位砂砾石沉积的展布、沉积特征、砾组特征及孢粉分析等研究,分析本套砂砾石层的成因及其气候环境记录,并结合区域资料,探讨其形成时代和新构造意义.分析结果表明,研究区高位砂砾石层可划分为Ⅰ级、Ⅱ级和Ⅲ级高位砂砾石层,沉积时代初步厘定为早全新世、晚更新世和中更新世.3级高位砂砾石层均为河流作用的冲积成因,水动力条件较强,略具冲积扇特征,分别为雅鲁河Ⅰ级、Ⅱ级阶地沉积记录和嫩江Ⅲ级阶地沉积记录.孢粉分析显示,Ⅱ级和Ⅲ级高位砂砾石层沉积时为针叶森林草原环境,气候温凉干旱;Ⅰ级高位砂砾石层沉积时为落叶阔叶森林草原环境,气候温暖偏干,其后变为草原荒漠环境,气候寒冷干旱.雅鲁河主河道晚更新世以来由东向西略有迁移,嫩江主河道中更新世以来由西向东不断迁移,雅鲁河断裂和嫩江断裂所夹的断块中更新世以来存在3期抬升.  相似文献   

9.
通过精细露头层序地层学的研究,将三叠纪标定了二级层序2个,三级层序9个。提出并厘定了层序旋回的等级系列:一级(200—400Ma),二级(10—100Ma),三级(1—10Ma),四级(0.1—0.2Ma),五级(0.2—0.05Ma)和六级(±0.02Ma)层序旋回。将三叠纪盆地划分为被动边缘(T1+2)和前陆盆地(T3)阶段。进一步标定了古构造沉降对有效容纳空间及层序形成的贡献。提出并规范了高频层序的内涵本质及其划分方案。建立并标定了不同物质背景之下的高频层序四种鉴定类型:三角洲河口坝或滨岸旋回序列型;波痕指数垂向有序变化型;厚层灰岩或白云岩与薄层灰岩或白云岩有序叠置偶合型和砂屑灰岩与砂、泥岩层偶型。高频层序行为堆叠样式及其所携带的信息可深刻地揭示三级层序的内部构架,提高地层对比精度。为建立高分辨率层序地层学和定量编制全球海平面变化曲线奠定了基础。  相似文献   

10.
通过对兰州段黄河Ⅱ和Ⅲ级阶地剖面的地层岩性、粒度分析和光释光测年等,认为剖面中被普遍界定为河漫滩沉积的一套厚几米至几十米具水平层理的细粒砂土层是以冲、洪积与黄土互层的交互式沉积,其开始沉积的时期与气候进入冰期或冰阶相对应。据此可将兰州段黄河阶地剖面地层划分为三部分,即:河流砂砾石层、加积层与风成黄土层,分析了这一地层结构的发育过程,指出沉积相的识别和划分对于阶地研究具有重要意义。  相似文献   

11.
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.  相似文献   

12.
Robert L. Linnen   《Lithos》2005,80(1-4):267-280
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.  相似文献   

13.
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).  相似文献   

14.
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  相似文献   

15.
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),  相似文献   

16.
17.
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-  相似文献   

18.
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-  相似文献   

19.
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.)  相似文献   

20.
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  相似文献   

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