New constraints to the geodynamic evolution of the southern sector of the Calabria–Peloritani Arc (Italy)Nouvelles données sur l'évolution géodynamique du secteur méridional de l'Arc Calabro-Péloritain (Italie)     

Glauco Bonardi  Paola de Capoa  Angelida Di Staso  Manuél Martı́n-Martı́n  Iván Martı́n-Rojas  Vincenzo Perrone  José Enrique Tent-Manclús 《Comptes Rendus Geoscience》2002,334(6):423-430

New studies have been carried out on the Tertiary of the Stilo Unit, the uppermost of the Calabria–Peloritani Arc southern sector, and the Stilo–Capo d'Orlando Formation, sealing the whole nappe stack. The Tertiary terrains linked to the Mesozoic cover of the Stilo Unit consist of the lowermost Oligocene Palizzi Formation and the Late Rupelian–Aquitanian Pignolo Formation. The possibility that they deposited before the emplacement of this unit as the highest tectonic sheet of the sector is suggested. The base of the Stilo–Capo d'Orlando Formation resulted of Burdigalian age in both type areas. This interpretation, together with the existing and new data, allows proposing an age close to the Aquitanian–Burdigalian boundary for the stacking of the whole Calabria–Peloritani Arc southern sector. To cite this article: G. Bonardi et al., C. R. Geoscience 334 (2002) 423–430.  相似文献   

辽河西部凹陷沙三段浊积岩储层中钙质夹层研究   总被引：29，自引：0，他引：29  

林承焰  黄金柱 《沉积学报》1996,14(3):72-80

本文阐明了辽河西部凹陷高升、兴隆台、曙光和冷东四个地区沙三段浊积岩油气储层内的钙质夹层识别标志，定性、定量地揭示了它在剖面和平面上空间分布规律，探讨了它的成因机制，指出了钙质胶结作用和钙质夹层对储层性质与油气分布的重要影响。  相似文献   

Calcareous nannofossils and the Santonian/Campanian and Campanian/Maastrichtian boundaries on the Brazilian Continental Margin: historical overview and state of the art     

Armando Scarparo Cunha  Rogério Loureiro Antunes  Jackie A. Burnett 《Cretaceous Research》1997,18(6):823-832

Recognition of the Campanian stage on the Brazilian Continental Margin, using calcareous nannofossils, has been historically problematic. This paper constitutes an overview of earlier works, showing how nannofossil biostratigraphic ideas have evolved since Troelsen & Quadros provided the first biozonation of this region in 1971. Recent studied have provided data which have helped to clarify these apparent biostratigraphic problems, and allows this region to be placed in a global biostratigraphic context.The earliest researchers identified the Santonian/Campanian boundary by the last occurrences of ‘Lithastrinus grillii’ andPetrobrasiella venata. P. venatawas later abandoned as an index species due to its rarity and, instead, the last occurrences ofMarthasterites furcatusand ‘Lithastrinus grillii’ became the most-used markers. However, the stratigraphic age of these biohorizons diverged from those quoted in the literature. In the Brazilian basins, these extinctions, rather than having occurred in the Campanian as was recorded elsewhere, were considered to mark the top of the Santonian, as suggested by correlations with other microfossil groups (primarily foraminifera and palynomorphs). To explain this phenomenon, the existence of a condensed sequence was postulated for most of the Brazilian marginal basins, where the uppermost Santonian deposits were apparently indistinguishable from those of the lowermost Campanian. In line with current correlations presented in the nannofossil literature, and with new information obtained from core and side-wall samples, it is now believed that the extinction of these speciesdidoccur in the Campanian in the Brazilian basins, whilst the last occurrence ofLithastrinus moratus(previously misidentified asLithastrinus grillii) has become a useful Santonian marker. Thus the Santonian/Campanian boundary in Brazil lies in a stratigraphic position similar to elsewhere in nannofossil terms, that is below CC18.The Campanian/Maastrichtian boundary was initially characterised in nannofossil terms in Brazil by the last occurrence ofBroinsonia parca constricta, and later by the last occurrence ofEiffellithus eximius. Recently acquired data has shown that the sequence of events in the Brazilian marginal basins is similar to that of the Sissingh/Perch-Nielsen standard biozonation scheme through this interval. Again, correlations in the literature with the recently defined boundary (in macrofossil terms) thus allow the boundary to be determined between the last occurrences ofBroinsonia parca constrictaandUniplanarius trifidus, that is, in CC23b.  相似文献   

东太平洋中新世钙质超微化石及其地层学、古海洋学意义     

李日辉  孟祥营 《海洋地质与第四纪地质》1992,(3)

本文研究了《海洋四号》87—88两个航次CC—48和CC(c)—9两岩心的钙质超微化石。共鉴定出7属13种。CC—48岩心自上而下可分为3个钙质超微化石组合,其中组合3和2分别相当于NN2和NN3带;CC(c)—9孔722cm以下的钙质超微化石属于一个组合,大致相当于NN3—4带。两孔所见最老沉积皆为早中新世。同时根据CC(c)—9孔NN3—4带中广泛见有Discoaster exilis化石,认为在该区其地史分布可下延至NN3带(最迟不晚于NN4带)。并结合CaCO_3含量、溶解指数及丰度变化,在早中新世钙质软泥沉积中识别出两个较强的溶蚀期,认为是南极底层水强烈活动所致。  相似文献   

Upper Cretaceous deposits in the northwest of Saratov oblast,Part 1: Litho- and biostratigraphic analysis of the Vishnevoe section     

A. G. Olfer’ev  V. N. Beniamovski  V. S. Vishnevskaya  A. V. Ivanov  L. F. Kopaevich  E. M. Pervushov  V. B. Sel’tser  E. M. Tesakova  V. M. Kharitonov  E. A. Shcherbinina 《Stratigraphy and Geological Correlation》2007,15(6):610-655

The work is dedicated to multidisciplinary study of Upper Cretaceous deposits exposed at the day surface in a ravine near the village of Vishnevoe, the Petrovsk district of Saratov oblast. The exposed section includes deposits of the Bannovka, Mozzhevelovyi Ovrag, Mesino-Lapshinovka, Rybushka, Ardym, Lokh formations and of the Borisoglebsk sequence first distinguished in the Volga River basin. Age ranges of the formations studied are confirmed or defined more precisely (the Ardym and Lokh formations) based on fossil faunas of cephalopods, bivalves, radiolarians, planktonic and benthic foraminifers. The middle-upper Coniacian range of the Borisoglebsk sequence is substantiated. Distribution of brachiopods, sponges, radiolarians, ostracodes and calcareous nannoplankton in the section is established. Radiolarian assemblages are used to distinguish biostratigraphic subdivisions corresponding in rank to faunal beds. Based on nannofossil assemblages, zones and subzones of standard zonations after Perch-Nielsen (1985) and Burnett (1998) are established. Stratigraphic ranges of certain radiolarian, ostracode and calcareous nannoplankton taxa are verified.  相似文献   

铜陵凤凰山岩体的地质地球化学特征     

邵拥军  彭省临  刘亮明  吴淦国 《矿产与地质》2003,17(5):627-629

着重探讨了凤凰山岩体的地质和地球化学特征，并从地球化学的角度分析了岩体的成因，认为凤凰山岩体为复式岩体，形成于燕山晚期。原始岩浆来源于上地慢碱性玄武岩浆，成岩构造环境为造山带和岛弧环境，成岩过程中经受了钙质围岩的同化混染。  相似文献   

安徽省祁东煤矿底砾含水层突水灾害成因与治理技术   总被引：5，自引：0，他引：5  

孔一繁  汪永茂 《中国地质灾害与防治学报》2003,14(4):67-70

文章介绍了皖北煤电集团公司祁东煤矿3222工作面特大突水灾害过程，并根据“四含”水文长观孔水位，突水后水温变化特点、水质化验资料及防水煤岩柱构成，分析出水水源为：第四系“四含”水；导水通道可能为：①采动裂隙沟通风化网络裂隙；②工作面中部存在垂向导水裂缝带，使“四含”水下泻所致。通过对突水性质和水情发展趋势的分析研究，决定采用强制排水、建防水闸墙、水泥浆封盖“四含”和基岩风化带堵出水水源；粘土浆充填固结采空冒裂带的治理方案。实施后，堵水率达100％，仅用102d就恢复了矿井生产，安全撤出了综采支架，取得了良好的经济效益和社会效益。  相似文献   

内蒙古巴彦诺日公地区构造砾岩特征及其形成机制     

李新仁  贾利亚  陈志勇  苏宏伟  张志祥 《西北地质》2003,36(4):25-29

通过巴彦诺日公地区1／5万地质填图和重点解剖研究，认为原1／20万区调中所划下元古界阿拉善群大部分岩石组合可与内蒙古中部地区色尔腾山岩群进行对比，且祖宗毛道组三段实际上是一套构造砾岩。在研究该砾岩宏观和微观特征的基础上，认为其形成机制为伸展机制下的构造拆离。  相似文献   

巴丹吉林沙漠湖泊及其下游地下水同位素分析   总被引：31，自引：3，他引：31       下载免费PDF全文

陈建生  凡哲超  汪集旸  顾慰祖  赵霞 《地球学报》2003,24(6):497-504

本文通过环境同位素水化学等分析方法研究了祁连山北侧、龙首山、巴丹吉林沙漠、古日乃、拐子湖和额济纳盆地的泉水和井水的来源 ,揭示了巴丹吉林沙漠等下游地区的地下水来自于祁连山降水的补给 ,平均补给高程为 330 0m ,祁连山顶部存在大片裸露的灰岩地层 ,雪水融化后沿着喀斯特地层或山前大断裂补给到深部 ,穿过龙首山直接补给到巴丹吉林沙漠及其下游地区 ,在沙漠湖泊中发现的钙华与钙质胶结证明地下水经过了石灰岩地层 ,承压水通过越流补给到浅部含水层 ,通过蒸发量计算得到的地下水补给量接近 6× 10 8m3 /a,承压水中地下水的年龄为 2 0～ 30a。  相似文献   

砾岩边坡稳定性分析与防治工程   总被引：2，自引：0，他引：2  

滕伟福  杨冬英  贾洪彪 《水文地质工程地质》2003,(Z1)

沪蓉国道主干线宜昌至恩施段高速公路,是国家“五纵七横“交通网的重要组成部分,其砾岩边坡稳定性分析与防治工程是重要的研究课题。本文以砾岩岩体结构面模拟研究,岩体力学参数估算为基础,结合砾岩特征及边坡地质环境条件,提出砾岩边坡稳定性评价的地质模型,并采用数值模拟与计算,得出砾岩边坡稳定性分析的确切结果。砾岩边坡岩土工程加固设计是关系到该高速公路安全、经济、适用的重要内容,紧密结合砾岩边坡的地质环境和砾岩岩体特征,采用信息化设计,运用生态化设计理念,充分发挥岩土工程技术优势,保护环境,提出合理的岩土工程加固设计方案。本研究成果对砾岩边坡防治工程提出了系统的研究思路,对沪蓉国道主干线宜昌至恩施段高速公路砾岩边坡的设计与施工具重要意义。  相似文献