贵州罗甸大文二叠三叠系界线剖面海平面变化及其全球对比

对华南地区贵州罗甸大文剖面早三叠世早期的凝块石进行了系统的沉积学描述,区分出斑状、层状、枝状和网状4种中型构造。凝块石所具有的沉积构造特征和岩石学统计数据表明其形成于潮下带沉积环境,其中,斑状和层状中型构造的凝块石形成于能量较低的深潮下带,而枝状和网状中型构造的凝块石形成于能量较高的浅潮下带。18个向上变浅的沉积旋回显示Hindeodus parvus带内部海平面逐渐降低;Isarcicellastaeschei带和I.isarcica带早期,海平面降到最低,之后海平面开始升高。通过与其他地区二叠–三叠系界线剖面的海平面变化情况对比发现,全球普遍存在二叠–三叠纪之交的海平面下降,而大文剖面早三叠世早期的H.parvus带、I.staeschei带和I.isarcica带的海平面变化情况在古特提斯洋范围内可以广泛对比,可能主要受到全球海平面变化的影响。     

江西信丰铁石口剖面晚二叠世的牙形石动物群

对江西省信丰县铁石口剖面晚二叠世长兴阶至铁石口阶下部的牙形石动物群有了新的认识。基于牙形石的研究,将该地区晚二叠世的地层划分为3个牙形石生物带,自上而下分别是：Clarkina changxingensis yini带;Clarkina postwangi带;Clarkina changxingensis带。探讨了浙江长兴煤山标准剖面晚二叠世长兴组至殷坑组下部的牙形石生物带的划分,将这段地层划分为4个牙形石带,自上而下分别是：Clarkina meishanensis meishanensis带; Clarkina changxingensis yini-Clarkina meishanensis zhangi带;Clarkina postwangi和Clarkina subcarinata-Clarkina changxingensis组合带,而最下部的一个带又分为2个亚带,即上部的Clarkina changxingensis亚带和下部的Clarkina subcarinata-Clarkina wangi亚带。最后将铁石口剖面与煤山剖面进行了牙形石生物地层对比,认为铁石口剖面除了长兴组下部被第四纪河床覆盖之外,晚二叠世上部的地层可以完全与煤山剖面进行对比。     

四川盆地二叠系牙形石研究及其油气意义

二叠系以海相碳酸盐岩地层为主,是四川盆地的重要产气层之一。作者对33条剖面进行了系统的工作,在取得丰富牙形石资料的基础上,对该区二叠系的地层划分与对比,二叠系至三叠系底部的Neogondolella和Anchignathodus属的演化系列,沉积相与牙形石的关系,和根据上二叠统牙形石色变判断上三叠统油气成熟度指标等进行研究     

牙形石研究概略

牙形石生物地层的研究一直为地质工作者所重视,其具有十分重要的使用价值和学术价值[1]。在使用上可以作为地层划分及对比的重要工具,如全球二叠-三叠系界线,即三叠系的底界,由Hindeodus parvus的首现点定义[2];在学术上,对牙形石的研究可以促进人们对于地质历史时期发生的重大生物灭绝及复苏事件的认识。     

淮北煤田早二叠世植物群落及其组合特征

本文详细研究了淮北煤田早二叠世地层植物化石1300余块,其分属于10大类共69属165种。该区早二叠世植物化石丰富,保存良好,是典型的华夏植物群。根据该期植物群的纵向发育规律和空间分布特点,其可划分为两个植物组合,即早二叠世早期山西组的Cathaysiopteris whitei-Callipteridium koraiense-Cordaites schenkii组合带和早二叠世晚期下石盒子组的Lobatannularia ensifolia-Gigantonoclea spp.-Caulopteris spp.组合带。     

广西西部早、中三叠世牙形石序列

广西三叠系分布广泛,厚度较大,所含化石的种类、数量都很丰富。但是过去对牙形石及其生物地层学的研究几乎为空白,仅见西林县万炮早三叠世的一些牙形石属种的记载。近年来,作者研究了广西西部田东、平果、扶绥和崇左的早、中三叠世碳酸盐岩地层的牙形石,为广西三叠纪生物地层学提供了新资料。本文仅就牙形石序列论证如下。     

云南省东部罗平地区晚三叠世卡尼期菊石生物地层

描述了产于云南省东部罗平地区牛补歹剖面上三叠统“法郎组”瓦窑段菊石带Trachyceras multitube- rculatum带之上地层中的菊石4属8种(含1比较种和3未定种), 其中Trachyceras aonoides, Simonyceras simonyi系国内首次报道。 依据各物种组合特征及其地层分布情况, 自下而上识别出菊石Trachyceras aonoides带和Austrotrachyceras triadicum带, 时代上大致对应晚三叠世早卡尼期的中晚期。     

云南省东部罗平地区晚三叠世卡尼期菊石生物地层

描述了产于云南省东部罗平地区牛补歹剖面上三叠统"法郎组"瓦窑段菊石带Trachyceras multitube-rculatum带之上地层中的菊石4属8种(含1比较种和3未定种),其中Trachyceras aonoides,Simonycerassimonyi系国内首次报道。依据各物种组合特征及其地层分布情况,自下而上识别出菊石Trachyceras aonoides带和Austrotrachyceras triadicum带,时代上大致对应晚三叠世早卡尼期的中晚期。     

峨眉山早二叠世的苔藓虫化石

峨眉山早二叠世地层发育,化石丰富,含大量苔藓虫化石。栖霞组以Fenestella sp.(A)为特征,茅口组下部以Araxopora hayasakai最丰富,上部则以Meekopora emeishanensis(sp.nov.)为特色。Meekopora属在我国过去仅发现于石炭系,现该属首次在蛾眉山下二叠统中发现,其层位大致相当子北美早二叠世的瓜达卢普组(Guadalupian)。     

鄂尔多斯盆地中晚三叠世延长期沉积演化

基于多年对鄂尔多斯盆地中上三叠统延长组的研究成果,结合近年来对盆地东、南邻区宁静盆地、沁水盆地、济源盆地、南召盆地等同期地层的野外实测以及地球化学、年代学等的研究结果,对鄂尔多斯盆地中晚三叠世延长期的岩性特征、地层厚度、地层接触关系、沉积相类型等进行对比研究。结果表明,研究区周缘中晚三叠世的岩性粒度变化、地层厚度及地层上下接触关系与鄂尔多斯盆地沉积背景具有一致性;沉积相带演化从时间尺度和空间尺度上讲,从邻区向鄂尔多斯盆地内部过渡变化符合瓦尔特相律,符合中晚三叠世华北板块构造的演化背景。研究后认为,中晚三叠世,周缘盆地与鄂尔多斯盆地应属同一个大型沉积盆地,这将中晚三叠世鄂尔多斯原型盆地向东部和南部延伸,包括了宁静盆地、沁水盆地、济源盆地、南召盆地等盆地。该研究为中晚三叠世鄂尔多斯盆地原始沉积面貌的恢复提供了新的依据。     

推荐一条GSSP的辅助剖面

该文赞同以Ｈｉｎｄｅｏｄｕｓ ｐａｒｖｗｓ的首次出现作为划分二叠－三叠系界经的生物标志，笔者强调只有以正模及其描述为准所厘订的Ｈ、ｐａｒｖｕｓ，且以主齿、细齿保存完美、距界线粘土层顶面位置最低以及其顶面至界线生物面之上均为单一岩相的Ｈ、ｐａｒｖｕｓ的首次出现点位，才有可能成为二叠－三叠系全球界线层型剖面点的位置、东岭剖面可以它典型的Ｈ．ｐａｒｖｕｓ距界线粘土层顶面仅高出１３ｃｍ，化石保存完好以及界     

A detailed Lower Triassic conodont biostratigraphy and its implications for the GSSP candidate of the Induan–Olenekian boundary in Chaohu, Anhui Province

Chaohu is located in a deep part of carbonate ramp on the Lower Yangtze Block, which belonged to the low-latitude eastern Tethyan archipelago during the Early Triassic. Fossils were very rich in the Lower Triassic of Chaohu. Bivalves, ammonoids, conodonts were very common throughout the Lower Triassic, while fish fossils were generally rich in some beds of the upper part. It is one of the most typical sections for the Early Triassic chronostratigraphy in the world. Although various fossils had been studied in the 1980s and 1990s, recent studies based upon new and more detailed collections from the Lower Triassic of Chaohu showed that the conodont zonation needs revision. We collected Lower Triassic conodont fossils from continuous sections of the West Pingdingshan, North Pingdingshan and South Majiashan, Chaohu, Anhui Province, and updated zonations were made for each section. Eight conodont zones have been distinguished. They are, in ascending order, Hindeodus typicalis zone, Neogondolella krystyni zone, Neospathodus kummeli zone, Neospathodus dieneri zone, Neospathodus waageni zone, Neospathodus pingdingshanensis zone, Neospathodus homeri zone, and Neospathodus anhuinensis zone. The first occurrence of Neospathodus waageni eowaageni of the N. w. eowaageni subzone （i.e. the base of the N. waageni zone） is suggested as the marker to define the Induan-Olenekian boundary.     

贵州关岭动物群时代的牙形石地层证据

通过对关岭动物群产出层位瓦窑组及其下伏地层竹杆坡组采集到的牙形石样品进行处理，得到典型牙形石带分子Paragondolella polygnathiformis和Paragondolella tadpole。经对比，可知竹杆坡组顶部和瓦窑组的时代为晚三叠世卡尼期中期或晚期，而不是中三叠世拉丁期，从而表明关岭动物群的时代是晚三叠世卡尼中－－晚期。     

贵州省盘县地区羊圈——-楚皮凹剖面中三叠统关岭组上段牙形石生物地层

选择贵州省盘县地区新民乡羊圈村附近羊圈-楚皮凹剖面中三叠统关岭组上段至杨柳井组下部地层进行牙形石生物地层再研究, 补充描述牙形石Neogondolella constricta cornuta, Neogondolella constricta longa, Neogondolella constricta balkanica, Neogondolella alpina alpina, Neogondolella cf. Neogondolella acuta, Paragondolella excelsa和Paragondolella tornaesis等物种, 丰富了该段地层牙形石多样性组成, 并重新划分牙形石带, 进行区内和区外对比。结果表明: 1) 羊圈-楚皮凹剖面关岭组上段至杨柳井组下部可划分5个牙形石带, 自下而上为Nicoraella germanica带(未见底界)、Nicoraella kockeli带、Neogondolella bifurcata带、Neogondolella constricta带和Neogondolella constricta cornuta带(未见顶界); 2) 该段地层牙形石序列区内可与贵州省青岩剖面垄头组上部(台缘斜坡)、关刀(2)剖面关刀岩楔(盆地边缘相)同名化石带对比, 区外与西特提 斯生物区菊石binodosus带、trinodosus带、reitizi带内的牙形石面貌组成相似; 3) 进一步证明该段地层时代为中三叠世安尼期Pelsonian亚期至Illyrian亚期中晚期, 但未进入拉丁期。     

Extinction pattern of reef ecosystems in latest Permian

Studies of two Permian-Triassic boundary (PTB) sections on top of a Changhsingian reef in Ziyun, Guizhou Province, southwestern China indicate that the end-Permian mass extinction of reef ecosystems occurred in two steps. The first step is the extinction of all stenotropic organisms such as calcisponges and fusulinids in the latest Permian (in the Clarkina yini conodont zone). The biota after the first extinction is simple, comprising eurytropic organisms including microgastropods, ostracods, and some small burrowing organisms, or only algal mats. At the beginning of the Early Triassic (i.e. the beginning of the Hindeodus parvus zone), the environments became anoxic, and the microgastropod dominated biota or algal mats disappeared, which constituted the second episode of the mass extinction. The biota after the second extinction comprises small spherical microproblematica, some kinds of specialized organisms tolerant of anoxic or oxygen-poor conditions. As the environments became oxygenated, the specialized biota was replaced by a microgastropod-dominated simple biota. When the environmental conditions improved further, the simple biota was replaced by a diverse biota with normal-sized ammonoids, bivalves, and gastropods, representing restoration of normal oceanic condi- tions. Comparison with PTB sections in Dolomites, Italy and Meishan, Zhejiang Province shows that non-reef ecosystems had a similar first episode of mass extinction in the latest Permian. In the case that oceanic anoxia happened, non-reef ecosystems had a second extinction episode similar to that of reef ecosystems.     

黔西南三叠系永宁镇组牙形石研究—兼论下,中三叠统界线

本文首次系统描述了贵州贞丰县龙场、关岭县永宁镇的永宁镇组牙形石5属12种;在永宁镇组中识别出4个牙形石组合带(层)(由下而上):1. Pachycladina obliqua-Parachirognathus delicatulus带,2. Neospathodus homeri-Neospathodus triangularis.带,3. Neogondolella cf. jubata-Neospathodus timorensis带,4. Neogondolella navicula navicula-Neogondolella constricta层;首次将下、中三叠统的界线置于 Neogondolella navicula navicula-Neogondolella constricta层之底,即永宁镇组第4段之底。两统之间为整合接触。     

新疆准噶尔与华南湘中法门期碳同位素特征的对比研究

针对新疆准噶尔盆地西北缘洪古勒楞组下段是否存在弗拉-法门阶界线的问题,对比研究布龙果尔剖面该段地层以及湖南中部锡矿山剖面上泥盆统法门阶中下部碳酸盐岩的碳同位素特征,并结合已有的生物地层学证据,重新讨论洪古勒楞组下段的时代。结果表明,布龙果尔剖面洪古勒楞组下段碳同位素的变化趋势与国内外诸多典型剖面弗拉-法门期之交的δ~(13)C偏移明显不同:未见到显著正偏移;布龙果尔剖面δ~(13)C在0~1‰范围内变化,小于国际上目前已知的弗拉-法门期之交δ~(13)C正偏移的幅度(2‰~3‰)。布龙果尔剖面洪古勒楞组下段可能不存在弗拉期地层,甚至可能缺失法门阶底部(牙形石Pa.triangularis带)。法门早中期,布龙果尔剖面碳同位素曲线可与湖南锡矿山剖面同时期地层进行较好的对比,分为3个阶段:2个完整的正偏—负偏旋回以及之上的小幅正偏。主量元素特征表明,布龙果尔剖面第3-1层的下半部受陆源物质影响较大,推测可能与区域构造活动变强烈有关。     

Calcimicrobialite after end-Permian mass extinction in South China and its palaeoenvironmental significance

Calcimicrobialites, which could be correlated to the layer 27 in Meishan section according to the Hindeodus parvus, occur abruptly on the end-Permian mass extinction boundary in South China. Microbialites mainly distribute on the top of reef facies or shallow carbonate platforms, thinning into deep facies. All the microbialites discovered are composed of micrite and coarse crystal digitate carbonate or patch carbonate. Microfossils usually dominate in the microbialites, and small gastropods, bivalves and ostracodes can also be found. This fossil assemblage represents a simple but particular remanent biota after the end-Permian mass extinction on the top of reefs or shallow carbonate platforms.Abrupt occurrence of microbialites above the mass extinction boundary is the ecological response to the end-Permian global event in reef or shallow carbonate facies. Many studies have been done on the Permian-Triassic boundary and event in deep water facies sections or middle to lower shelf facies sections. However, the calcimicrobialites in South China are mainly located above reef facies or shallow carbonate platform facies. It will surely be helpful for people to know more about the different responses in different depths of ancient marine environment during the transition between Permian and Triassic by the study of petrology,palaeontology and palaeoecology of the calcimicrobialites.     

渭北地区石炭纪牙形刺初步研究

本文对渭北地区石炭纪地层中采集的牙形刺进行了研究。经鉴定,共获得牙形刺6个属,8个种和6个未定种。其中中石炭统本溪组以Streptognathodus cf.parvus和?Idiognathodus corrugatus为代表;上石炭统太原组下部以Streptognathodus gracilis为代表;中部以S.oppletus,S.elegantulus和Idiognathodus delicatus为代表;上部经与其它地区同时期的牙形刺相比,缺失了以S.elongatus和S.wabaunsensis为代表的矛形刺动物群。