湖南邵东县中泥盆统棋梓桥组介形类化石及其地质意义

1978年夏,笔者在观察邵东县光坡公社马鞍山之泥盆系剖面时,在中泥盆统棋梓桥组下部采到了丰富的介形类化石,它们的属种多、数量丰富、组合特征明显,有一定的古生物学和地质学意义。     

湖南道县、宁远一带中泥盆统棋梓桥组中的台地前缘斜坡异地碳酸盐沉积

沿台地边缘斜坡沉积的古代碳酸盐再沉积物是最近十年来才引起沉积学者广泛注意的一种深水碳酸盐类型,包括碳酸盐重力流,重力滑动(滑塌)沉积及塌磊裙。重力流及由于重力作用引起的沉积物与浅水碳酸盐或深水原地碳酸盐沉积相比,有很大的差异。它们的主要岩石类型是异地碳酸盐,为一套在重力作用下顺坡而下流动的碳酸盐沉积物。前礁塌磊是台地边缘礁坠落到陡崖下的礁块堆积,也称为礁崖塌积。     

浏阳县石坳上中泥盆统棋梓桥组超覆现象及其意义

1982年我队在开展永和—张坊地区1:5万区测工作时,于浏阳县永和镇东南八公里处石坳上,见到一套碎屑岩夹灰岩的地层,直接不整合于雪峰期花岗岩体和冷家溪群之上,当时认为是跳马涧组,省地质科学研究所王根贤则认为是古陆边缘棋梓桥组的超覆。尔后王和我们一起赴该地进行剖面研究,结合化石鉴定,予以肯定。这一事实的发现对研究我省棋梓桥组超覆现象,分析湘中地区中泥盆世晚期的古地理环境和沉积相都具有一定意义。石坳上位于高坪向斜的北东部扬起端(图1)。棋梓桥组出露长2公里,宽300米,     

大庸市张家界中泥盆统云台观组沉积相分析

张家界地区是我省著名的风景旅游区。该区系由中泥盆统云台观组砂岩形成的砂岩峰林地貌为特色。这种地貌特征,吸引着中外旅游观尝者和地质工作者的浓厚兴趣。但前人对其沉积相,尚未进行过专门的研究。笔者通过实测剖面和系统收集相标志资料,综合化石、岩性、沉积构造、粒度分析等,将云台观组划分为后滨、前滨、近滨等五个亚相,建立了湘西北地区云台观组沉积相模式。     

桂林地区上泥盆统碳酸盐岩沉积相

前言 桂林地区上泥盆统主要是一套海相碳酸盐地层,为岩溶发育的主要岩石之一。同期异相明显,可以划分为两个岩相:一是白云岩灰岩相,下部为桂林组,上部为融县组,整合接触,二是硅质岩扁豆状(瘤状)灰岩相,下部为榴江组,上部为三里组,整合接触。桂林组可与榴江组对比,属晚泥盆世早期沉积,融县组与三里组相当,属晚泥盆世晚期沉积。它们与下伏的中泥盆统东岗岭组为整合接触,而与上覆的下石炭统岩关阶呈整合或假整合接触关系。     

湖南祁阳上泥盆统佘田桥组有孔虫

本文首次报道我国湖南上泥盆统余田桥组有孔虫化石13属22种,其中包括1新种。这些有孔虫自下而上可分成三个组合,它们大多数可与苏联上泥盆统弗拉斯阶有孔虫对比,时代属晚泥盆世弗拉斯期。本文仅描述佘田桥组较重要的有孔虫8属10种。     

内蒙古东乌旗地区中下泥盆统泥鳅河组沉积相研究

发育于内蒙古东乌旗地区的泥鳅河组,属于早中泥盆世沉积,厚度约1000m,主要发育泥岩、粉砂岩和灰岩沉积,粉砂岩中常常发育大量腕足类和珊瑚生物化石。首次在本区发现风暴沉积和Beaconites遗迹化石:风暴沉积由下至上包括粒序层理段、平行层理段、丘状交错层理段和浪成波纹层理段4个层段;Beaconites遗迹化石具管壁和内部水平“V”字型的回填纹构造。通过对岩相、生物化石、风暴沉积和Beaconites遗迹化石的研究显示,东乌旗地区泥鳅河组为浅海相沉积。     

湖南中泥盆统一下石炭统海参化石

本文描述了湖南中泥盆统—下石炭统海参化石6个属、12个种(1个新属、8个新种):T huroholia crassa sp. nov., Th. hexangularia sp, nov., Th.pulchra sp. nov., Th. marginata Langenheim＆Fpis, Th. regularis sp. nov., paraeocaudina minularis gen. et sp. nov., Paracucumarites asymmetricus sp, nov., Protocaudina traquairii(Ftheridge). Pro. symmetrica sp. nov., Microantyx betoni Gutschick. Mortensenites teat sp. nov,, 讨论了它们的地层分布和地层对比。此外,扼要地介绍了海参化石基本构造及其地层意义。     

宁夏牛首山地区中—上泥盆统沉积相组合特征

在阿拉善和华北陆块南缘结合部位的牛首山地区,出露一套连续的中—上泥盆统陆相沉积组合。该套沉积组合的沉积相和沉积物源区的变化特征,可帮助理解阿拉善和华北陆块及相邻地区晚古生代构造演化。根据野外研究结果,该套沉积组合在牛首山南麓石峡沟地区呈现河流相、湖泊相和小型冲积扇相共同发育的沉积面貌,可分为河道、堤岸、河漫平原、滨湖、浅湖、扇根、扇中和扇端共8个沉积亚相。其中,中泥盆统石峡沟组总体呈现由河流沉积向湖泊沉积过渡,而上泥盆统老君山组则呈现下部为扇根、扇中、扇端亚相与河道亚相的粗碎屑沉积,上部由滨湖沉积向浅湖沉积过渡的沉积组合变化特征。牛首山地区老君山组砾岩层数、厚度及砾石砾径分别呈现向南逐渐减少、减薄和减小的特征。古水流分析结果显示,石峡沟组下部碎屑沉积物来自于北东东—东向物源区,上部沉积物主要来自于南东向物源区,而老君山组沉积物主要来自于北东向物源区。结合前人对老君山组古水流的系统测量、石峡沟组和老君山组砂岩碎屑锆石研究结果以及区域地质资料综合分析,认为中—晚泥盆世时期阿拉善地块东南缘总体具有北高南低的古地理格局,且该时期的沉积物为一套具有向南水体逐渐加深的陆相沉积组合,沉积物源区主要位...     

湖南东波-平和地区中上泥盆统岩石学特征及沉积相分析

通过对湘南东波-平和地区中上泥盆统岩石学特征的详细研究,划分出了滨海相带、局限台地相带和半局限台地相带等三个沉积相带以及滨海陆屑滩相、浑水潮间泥坪相、清水潮间泥坪相、潮间混乱合坪相、潮沟相、潮汐滩相、潮下浅水相等七个相型。根据对沉积环境的古构造背景,各相型基本特征的分析及时空分布规律,建立起了该区的沉积相模式。     

湖南省南部泥盆系中统棋梓桥组Pb.Zn.Fe.Mn含量特征

湖南南部地区(以下简称湘南)棋梓桥组广泛分布(图1),是一个重要的含铅锌矿层位。据最近统计,湘南有1/3的铅锌矿床(点)产于此层位中。棋梓桥组本身的厚度(47—1048米)相对于全区地层总厚(933—27808米)是微不足道的,可是却能集中如此之多的矿床(点),自然要引起人们的重视。近年来,随着层控矿床研究的深入,人们自然就把它与成矿相联系,也就是说把它看作是矿源层或就矿层。作为就矿层这是毋庸置疑的,作为矿源层     

Tidal deposits of carbonate facies and their microfacies types in the Qiziqiao Formation of Middle Devonian,South China

Tidal-flat and shoal deposits of carbonate fades in the Qiziqiao Formation are widely distributed over the vast areas of Guangxi, Guangdong and Hunan provinces, constituting an important stratigraphic unit where strata-bound and stratiform ore deposits (galena-sphalerite-pyrite) are found. These types of ore deposit seem to have close relations to the tidal deposits. Recognition of tidal deposits is based upon rock fabric, texture, structure, fossil assemblage, and particular sedimentary cycle. The typical sequence of tidal-flat deposits consists mainly of three units:Amphipora limestone, laminated limestone and dolostone (from the bottom to the top). This sequence represents a complete process of sedimentation from low-tideflat through intertidal to high-tideflat or supratidal. The sequence of shoal deposits of carbonate facies consists chiefly of grainstone and algal oösparite. Two major types of tidal deposit (open and restricted marine facies) can be distinguished, with eleven microfacies as follows: 1) calcarenite (grainstone) with sparite (MF-1); 2) algal oösparite (MF-2); 3) oncolite (alga-, or stromatoporoid-encrusted grains) (MF-3); 4) bioclastic grainstone (biosparite) or rudstone with sparite (MF-4);5) Amphipora limestone (MF-5); 6) dark fossil-poor micrite (MF-6); 7) pelsparite or peloidal grainstone with sparite (MF-7); 8) laminated pellet mudstone-wackstone (MF-8); 9) micrite with onkoids (MF-9); 10) rudstone or floatstone (MF-10; and 11) bedded dolomite-gypsum-dolomite (MF-11).     

四川龙门山地区中泥盆统金宝石组混合沉积特征

四川龙门山地区是中国泥盆系出露较好、研究程度较高的地区。中泥盆统金宝石组发育由碎屑岩、碳酸盐岩、混积岩组成的混积沉积。本研究以平武县平驿铺剖面和北川县甘溪剖面为切入点,基于实测资料和薄片观察对金宝石组沉积相开展详细研究,认为龙门山地区中泥盆统金宝石组发育河流、碎屑滨岸、陆棚和碳酸盐岩缓坡4种沉积相,沉积演化经历了2个沉积旋回。金宝石组以相混合和原地混合2种方式形成混合沉积。相对海平面的变化、陆源碎屑的供应、碳酸盐生产速率和古气候是引起相混合的主要控制因素,波浪和风暴浪则是引起陆源碎屑和碳酸盐组分混合沉积的主要作用方式。对金宝石组沉积序列、沉积特征及沉积演化过程的研究,有利于增进对龙门山地区泥盆系沉积古环境的认识。     

贵阳乌当泥盆系马鬃岭组上部地层中的遗迹化石

本文首次描述贵阳乌当泥盆系马鬃岭组上部地层中产出的遗迹化石10属,lO种（其中1个新遗迹种）,并对这些遗迹化石产出层位的沉积环境作了初步分析,认为主要属于Seilacher（1964,1967）的Skolithos遗迹相,为水动力条件较强的高能滨海沉积环境。     

湖南邵东下石炭统刘家塘组的介形类

湖南邵东下石炭统刘家塘组产丰富的介形类化石，计有１８属３５种（包括６新种），它们绝大多数可与国内外下石炭统介形类对比，其地质时代为早石炭世杜内期，刘家塘组介形类明显地可分成上、下两个不同组合。本文仅描述了刘家塘组介形类６属７种（包括６新种）。     

Growth Dynamics of the Middle Devonian Jukoupu Bioherm,Xinshao, Hunan

The growth process, palaeoecological features and the function of organisms in reef-building of the Jukoupu bioherm in Hunan are discussed in detail. The bioherm is divided into 10 microfacies. Organisms are very abundant in the reef. Thirty-two genera Belonging to 7 phyla have been recognized. They make up 5 communities composed mainly of stromatopoids, Corals and algae, each of which has its own salient ecological features. An analysis of all communities shows that the organic functions are very complex. The same organisms may possess diverse functions simultaneously as the reef growth enters the late stage. The growth process of the reef may involve five stages' (l)biostrome stage, (2) stabilization stage, (3) frame-type reef-building stage, (4) binding and covering-type reef-building stage, and (5) baffle- type reef -building stage.     

湖南省涟源凹陷泥盆纪佘田桥组页岩储层测井评价

湘中地区涟源凹陷泥盆纪佘田桥组(D3s)富有机质页岩发育,区内参数井-湘新页1井(XXY-1)已在该组钻遇良好页岩气.为研究该套储层特征,依托湘新页1井的岩心和测井资料,通过数控测井系统的综合测井曲线响应特征和数据处理结果对该套储层进行了评价.结果表明,湘新页1井泥盆纪佘田桥组底部为优质页岩发育段,厚度达81.1 m,页岩TOC、物性均较好,具有较大资源潜力.     

湘中及湘东南地区上泥盆统佘田桥组页岩气勘探前景

湘中及湘东南地区泥盆纪佘田桥组具有良好的页岩气成藏条件,为页岩气勘探远景区。选取地质条件优越、页岩气特征明显的泥盆纪佘田桥组含气页岩作为主要研究对象,对页岩气储气特征和勘探开发潜力进行了分析。研究表明：含气页岩层分布面积广、有机碳含量高（TOC均值0.61%）、热演化程度高（Ro均值2.71%）,低孔低渗（孔隙度为0.7%,渗透率小于0.04×10^-3μm2）,且吸附能力强。含气页岩层厚度展布在凹陷盆地形成独特的“中心薄边缘厚”格局,结合其成藏特征和物化指数,划分出页岩气潜力较大的四个有利区。     

Depositional environments in an extensive tide-influenced delta plain, Middle Devonian Gauja Formation, Devonian Baltic Basin

The Middle Devonian Gauja Formation in the Devonian Baltic Basin preserves tide‐influenced delta plain and delta front deposits associated with a large southward prograding delta complex. The outcrops extend over 250 km from southern Estonia to southern Lithuania. The succession can be divided into 10 facies associations recording distributary channel belts that became progressively more tide influenced when traced southwards towards the palaeo‐shoreline, separated by muddy intra‐channel areas where deposition was characterized by crevasse splays, delta plain lakes, abandoned channel deposits and tidal gullies. Tidal currents influenced deposition over the entire delta plain, extending up to 250 km from the contemporary shoreline. Tidal facies on the upper delta plain differ from those on the lower delta plain and delta front. In the former case, deposition from river currents was only occasionally interrupted by tidal currents, e.g. during spring tides, resulting in mica and mudstone drapes, and distinctive graded cross‐stratification. The lower delta plain was dominated by tidal facies and tidal currents regularly influenced deposition. There was a change from progradation to aggradation from the lower to the upper part of the Gauja Formation coupled with a vertical decrease in tidal influence and a decrease in coarse‐grained sediment input. The Gauja Formation contrasts with established models for tide‐influenced deltas as the active delta plain was not restricted by topography. The shape of the delta plain, the predominant southward (basinward)‐directed palaeocurrents, and the thick sandstone succession, show that although tidal currents strongly influenced deposition at bed scale, rivers still controlled the overall morphology of the delta and the larger‐scale bedforms. In addition, there are no signs of wave influence, indicating very low wave energy in the basin. The widespread tidal influence in the Devonian Baltic Basin is explained by changes in the wider basin geometry and by local bathymetrical differences in the basin during progradation and aggradation of the delta plain, with changes in tidal efficiency accompanying the change in basin geometry produced by shoreline progradation.     

湖南桑植二叠系茅口组硅泥岩段的有机白云岩环境

湖南仁村坪剖面二叠系茅口组中段发育一套富有机质硅泥质岩,夹含有多层白云岩沉积。其白云岩的岩石学特征显示,白云石颗粒具有簇状低有序度隐晶质晶体特征,不同于次生白云岩的自形-半自形菱形的晶体类型,应属于沉积孔隙水体埋藏有机质的硫酸盐氧化过程产生的有机自生白云石类型。该层段碳-氧同位素表现出特征的负相关关系,与硫酸盐还原菌作用(SRB)的埋藏有机质氧化强度有关。生屑颗粒白云岩所表现出的重氧同位素特征,代表浅水环境有机质氧化过程特殊的氧同位素分馏途径。4.5m和5.9m处生屑白云岩表现的碳同位素强烈负偏,应与甲烷的硫酸盐缺氧氧化(AOM)过程有关。硅质泥灰岩和钙质泥岩因具有较低的孔隙度和早期碳酸钙沉降供应,难以充分发生与硫酸盐还原作用相关的自生白云石化,因而表现出甲烷生成作用带碱性孔隙水特征的重碳同位素组成特征。仁村坪剖面茅口组中段硅泥质岩段的岩石学特征、草莓状黄铁矿特征以及碳-氧同位素负相关关系等诸多证据,均显示其沉积环境处于斜坡相的富有机质供应和埋藏环境。