桂北额头村组-英塘组有孔虫带的建立及意义

桂北地区浅水碳酸盐台地上泥盆统额头村组-下石炭统英塘组有孔虫十分丰富,可划分为10个组合带,每个带均可进行大范围对比,是研究泥盆系/石炭系界线及建立以有孔虫谱系演化特征为标准的杜内阶/维宪阶界线的重要依据.     

广西泥盆纪四射珊瑚的分布与组合特征

广西早泥盆世晚期至晚泥盆世的碳酸盐台地区发育有两个不同的四射珊瑚群落,此二群落都有其各具特点的珊瑚组合系列。其中,在开阔台地相区的四射珊瑚可划分为9个组合带,而在台地边缘相区则可划分为8个组合带。在早泥盆世早、中期,因岩相分异不明显,四射珊瑚仅可划分为3个组合带。因此证明,四射珊瑚的发展演化与沉积相演变有密切的关系。     

广西融水地区上泥盆统融县组地层特征

广西融水地区上泥盆统融县组,在广西特别是在北部地区广泛发育,其层型剖面由于年代远久部分层段未能保存下来,长期以来,对该套地层的岩性特征存在较大争议。文章通过对两条剖面岩性组合特征的详细研究,认为广西上泥盆统融县组岩性特征总体由下往上为:白云岩—白云质灰岩—白云质含鲕粒灰岩—鲕粒灰岩—鸟眼灰岩及生物屑灰岩,颜色由浅变深,表明其属于晚泥盆世开阔台地相沉积为主,部分为滩后半局限、局限台地环境下的沉积类型。     

晚泥盆世大陆风化作用增强及其海洋环境效应:来自华南碳酸盐岩锶同位素的制约

上泥盆统弗拉斯阶和法门阶界线附近发生了大规模的生物灭绝, 其起因被认为是植物登陆导致的陆地化学风化作用加强及其引起的海洋水体缺氧所致, 但其直接证据还比较缺乏。运用广西地区广泛发育的浅海碳酸盐岩中锶元素(Sr)和同位素(87Sr/86Sr)、铀钍比值(U/Th)记录, 探究了从中泥盆统到下石炭统的陆地化学风化速率及海水氧化还原条件的变化。研究结果表明, 在晚泥盆世(法门阶早期)陆地化学风化作用加强, 导致海水中Sr浓度升高, 及更富集重的Sr同位素组分; 低的U/Th比值也显示该时期水体缺氧严重, 海水中U元素被还原到沉积物中, 导致海水中的U浓度降低。陆地表面化学风化的加强对晚泥盆世海洋水体氧化还原条件的波动以及海洋生物的灭绝有重要影响。      

广西杜内阶—维宪阶界线研究

广西杜内阶—维宪阶界线研究Ｐｈ．Ｍｕｃｈｅｚ，Ｗ．ｖｉａｅｎｅ（比利时地质调查所）１前言中国地质科学院与比利时地质调查所十年前曾共同研究华南地区上泥盆统与下石炭统的界线，并与典型地区比利时南部的狄南地区进行对比。当时主要是研究泥盆—石炭系界线层。由于...     

来宾地区中泥盆统东岗岭组泥页岩有机地球化学特征

文章分析了桂中坳陷东部来宾地区中泥盆统东岗岭组(以下简称中泥盆统东岗岭组)泥页岩总有机碳含量(TOC)、有机质成熟度(Ro)、饱和烃色谱等有机地球化学特征,对比国内外不同地区富有机质泥页岩的有机地球化学特征,发现中泥盆统东岗岭组泥页岩具有一定的生气基础和勘探潜力。在此基础上,探讨中泥盆统东岗岭组泥页岩的沉积环境和有机质来源,发现中泥盆统东岗岭组泥页岩的沉积环境属于陆棚斜坡相缺氧还原的咸水环境,有机质来源多样,既有陆源高等植物,也有低等水生生物,有机质类型为Ⅰ-Ⅱ_1型。     

桂林南边村泥盆—石炭系界线层型剖面简介

广西桂林南边村剖面泥盆—石炭系界线地层发育良好,出露清楚,可作为泥盆—石炭系界线层型剖面。此剖面为迄今世界上所发现唯一的一条反映Siphonodella praesulca-ta—S.sulcata演化谱系并与现行泥盆—石炭系界线定义相一致的剖面。1988年5月国际泥盆—石炭系界线委员会已将南边村剖面列为泥盆—石炭系界线辅助层型候选剖面之一。 南边村剖面位于桂林市西北南边村南侧,距市中心6.6公里,交通方便。从村口沿小道步行200米至一小山脚下,该处泥盆—石炭系界线地层出露最佳(图1),南边村附近泥盆—石炭系界线地层连续出露,几乎未受构造影响。所出露的泥盆—石炭系界线地层位     

湖南中部中泥盆世的轮藻化石及其生活环境探讨

湖南中部长沙、宁乡、益阳、安化、涟源、邵东等县,中泥盆统跳马涧组和棋子桥组产丰富的轮藻化石,以宁乡县崔坪峡塘剖面为代表,有3属7种1型1新种,并首次发现了轮藻植物节部化石.建立了2个化石带(1)Trochiliscus ingricus-Eochara changshaensis组合带,分布在跳马涧组,时代为中泥盆世早期;(2)Sycidium顶峰带,分布在棋子桥纽,时代为中泥盆世晚期,并对轮藻的生活环境进行了探讨.     

东秦岭中泥盆世成矿海盆中一类特殊岩石—方柱黑云岩

赋存层控金属矿床的东秦岭中泥盆统中发育一类特殊岩石——方柱黑云岩。野外和室内研究表明,其为与火山及火山热卤水活动有关的地热异常海盆中的一种特殊沉积相。岩石学、矿物学、岩石化学、矿物化学及稀土元素特征也为其原岩经过卤水“浸泡”蚀变和埋藏热变质形成方柱黑云岩类的成因提供了令人信服的证据。据此,推测出秦岭中泥盆世层控金属矿床形成的地热异常背景。     

柳州石炭系划分新议

本文根据近几年来柳州市1:5万区调工作中所获得石炭系较多的地层古生物新资料,对柳州市石炭系划分进行探讨。文中较详细论述了泥盆系与石炭系界线、下石炭统内部界线、上下石炭统界线和石炭系与二叠系界线划分的新证据和认识。指出位于柳州市东郊马鹿山剖面产出较丰富的(?)类、珊瑚、牙形刺化石,为当前广西碳酸盐台地相区发育良好的石炭—二叠系界线剖面之一。     

河南登封二叠纪煤系地层植物化石组合

依据化石的层位分布和组成内容，登封二叠纪煤系地层植物群由下而上可划分为三个植物化石组合带：１．早二叠世中期山西组Ｅｍｐｌｅｃｔｏｐｔｅｒｉｓｔｒｉａｎｇｕｌａｒｉｓ－Ｔａｅｎｉｏｐｔｅｒｉｓｍｕｌｔｉｎｅｒｖｉｓａｓ－ｓｅｍｂｌａｇｅｚｏｎｅ；２．早二叠世晚期下石盒子组Ｇｉｇａｎｔｏｐｔｅｒｉｓｎｉｃｏｔｉａｎａｅｆｏｌｉａ－Ｃｈｉｒｏｐｔｅｒｉｓｒｅｎｉｆｏｒｍｉｓａｓｓｅｍｂｌａｇｅｚｏｎｅ；３．晚二叠世早期上石盒子组Ｌｏｂａｔａｎｎｕｌａｒｉａｈｅｉａｎｅｎｓｉｓ－Ｐｔｅｒｏｐｈｙｌｌｕｍｅｒａｔｕｍａｓ－ｓｅｍｂｌａｇｅｚｏｎｅ。另外，文中还讨论了这些植物组合的主要特点     

三门海游构造火山盆地之火山─沉积岩系层位归属讨论

本文根据天台测区1：5万区域地质调查工作成果，综合测区构造，岩石组合，岩石化学、化石，接触关系特征等资料分析，对三门海游构造火山盆内龙珠山─下路朱一带及芹溪、三门中学等地出露约70km2的火山─沉积岩系地层，进行层位归属讨论。指出海游盆地内龙珠山、里金、下路朱一带及芹溪、三门中学等地出露的火山─沉积岩地层，其层位应归属下白垩统永康群馆头组和朝川组，系属北北东向展布的早白垩世临海断陷地的组成部分。     

试论鲁中南地区下寒武统五山组沉积环境及岩相古地理

近几年来,我们在鲁中南地区开展了区域地质调查,对下寒武统五山组沉积环境及岩相古地理进行了专题研究,本文就是根据这一部分研究成果而写成的。由于水平有限,谬误难免,诚望指正。一、概述     

桂西北天峨地区下石炭统有孔虫带及地层划分

桂西北天峨地区孤立碳酸盐台地 ,上泥盆统顶部至上石炭统下部有孔虫十分发育 ,可划分 15个有孔虫生物组合带 ,它们是地层划分对比的重要依据。以有孔虫Eoendothyra与Quasiendothyra的灭绝、Bisphaera的大量出现划分泥盆系 /石炭系 ,以Eoparastaffella的出现作为维宪阶的底界 ,以Globivalvulina或Pseudostaffella的出现作为上、下石炭统的划分标志 ,生物分带明显 ,与岩石地层分界吻合或基本一致 ,是较理想的地层分界     

辽东半岛南部震旦-寒武系界限剖面古地磁特征

在辽东半岛南部震旦-寒武系界限剖面中采集了32块古地磁岩石标本。古地磁测试结果表明:①辽东半岛南部震旦系兴民村期曾出现一次极性倒转,它发生在650Ma左右,可称之为兴民村反极性期,据此,可与国外上先寒武系对比;②本区震旦-寒武系沉积地层曾经历了中纬度→低纬度→中纬度的古地理纬度区的变化历史;③初步建立了辽东半岛南部震旦-寒武系界限附近地层的视古地磁极迁移轨迹。根据古地磁测试结果,结合本区地层特征,将震旦-寒武系界限定在兴民村组与葛屯组之间,兴民村组的顶为震旦系的上限,葛屯组的底为寒武系的下限。     

Sedimentary facies of Maastrichtian to Danian deposits in Amur River area, Russian Far East

Sedimentary facies of the Tsagayan Formation is distributed in the eastern Zeya-Bureya Basin has been analyzed. The formation is of the Maastrichtian to Danian in age and characterized by the cyclicity of the fining-upwards successions. Analysis of environmental changes during the K/T boundary is the focus of this study. Five facies have been identified: Facies A, thick and laterally extensive coarse-grained to medium-gained sandstone units, interpreted as channelfill deposits; Facies B, parallel-laminated to massive mudstone units interpreted as interchannel lakes and flood plain deposits; Facies C, sheet-like medium-grained to fine-grained sandstones interpreted as crevasse splay deposits; Facies D, coal to coaly mudstone beds interpreted as deposits of peatlands; Facies E, very poorly sorted sandy mudstone beds interpreted as debris flow deposits. Fluvial environments with the low-relief fiat topography was inferred. A channel transported large volumes of clasts, and a flood basin with interchannel lakes and peatlands was deciphered. Any distinct change of sedimentary environments has not been identified throughout the Tsagayan Formation (including the K/T boundary). However, two beds of debris flow deposits were identified. The one occurs at the uppermost part of the lower Tsagayan Subformation and contains dinosaur fossils. The other is intercalated in the upper Tsagayan Subformation.     

Sedimentary facies of Maastrichtian to Danian deposits in Amur River area, Russian Far East

Sedimentary facies of the Tsagayan Formation is distributed in the eastern Zeya-Bureya Basin has been analyzed. The formation is of the Maastrichtian to Danian in age and characterized by the cyclicity of the fining-upwards successions. Analysis of environmental changes during the K/T boundary is the focus of this study. Five facies have been identified: Facies A, thick and laterally extensive coarse-grained to medium-grained sandstone units, interpreted as channelfill deposits; Facies B, parallel-laminated to massive mudstone units interpreted as interchannel lakes and flood plain deposits; Facies C, sheet-like medium-grained to fine-grained sandstones interpreted as crevasse splay deposits;Facies D, coal to coaly mudstone beds interpreted as deposits ofpeatlands; Facies E, very poorly sorted sandy mudstone beds interpreted as debris flow deposits. Fluvial environments with the low-relief flat topography was inferred. A channel transported large volumes of clasts, and a flood basin with interchannel lakes and peatlands was deciphered. Any distinct change of sedimentary environments has not been identified throughout the Tsagayan Formation (including the K/T boundary). However, two beds of debris flow deposits were identified. The one occurs at the uppermost part of the lower Tsagayan Subformation and contains dinosaur fossils. The other is intercalated in the upper Tsagayan Subformation.     

The First Discovery of the Earliest Devonian Conodont Zonal Fossil from the "Gavuu Member" in Mushgai Area of South Gobi,Mongolia

Conodont Caudicriodus woschimidti woschmidti has been found from a big outcrop (hill) of the Bayan-Kho-shuu Ruins Section which was previously assigned to the Silurian Gavuu Member of the Mandalovoo Formation. This isfirst time to find the lowermost Devonian conodont zonal fossil in Mongolia. The lower part of the Gavuu Member is Silurian. But the strata from where we collected samples M-9～M-12 definitely belong to Lower Devonian (lower Lochko-vian) rather than Lower Silurian. The Mandalovoo Formation should be named Mandalovoo Group, and its three members should be changed into three formations.     

Some biostratigraphically important palynomorphs from Paleocene Minato Formation,Iwate Prefecture,Northeast Japan

Palynological study of the Minato Formation, Noda Group, distributed in the vicinity of Kuji City, Iwate Prefecture, Japan is discussed in this paper. Biostratigraphically important palynomorphs including four angiosperm species, Triprojectus subspinulosus(Funkhouser) Braman, Triprojectus cf. spinulosus(Mtchedlishvili) Stanley, Paraalnipollenites confusus Hills et Wallace and Pistillipollenites macgregorii Rouse, and one fungi species, Pesavis tagluensis Elsik et Jansonius are described. Palyno-assembleges from the lower and the middle horizons of the Minato Formation are considered to indicate Danian in age, which corresponds well with the known fission-track dating. Palyno-assembleges from the lower and middle horizons of the Minato Formations are correlative with those from the Wuyun Formation and the Upper Tsagayan Subformation of Heilongjiang(Amur) River area in northeast China and the Russian Far East. Despite the similarity of the palyno-assembleges, differences in the diversity of angiosperms and species composition of some biostratigraphically important species are recognized between the two regions.     

山阳地区青石垭组风暴岩及其形成的构造背景

青石垭组风暴岩沉积序列与R.D.Kreisa等建立的理想沉积序列很相似,由下到上出现侵蚀突变的底面、贝壳滞积层和粒序层、纹理层(包括平行纹理、沙纹交错层理、浪成上叠沙纹层理、丘状交错层理及包卷层理等)和板岩层,并可分为近源和远源两种风暴岩,其中以后者为主。青石垭组风暴岩形成于扬子板块北侧相对稳定的古被动大陆边缘之上。