云南澜沧老厂矿区石炭系划分及原中上石炭统碳酸盐岩时代归属探讨

参照目前的石炭纪和二叠纪地层划分方案,笔者将云南澜沧老厂矿区石炭系与滇西凤庆平掌剖面石炭系进行对比,认为老厂矿区只存在相当于平掌组下段的地层;根据在矿区原中上石炭统"C2 3"碳酸盐岩中所采到的化石面貌显示,该套碳酸盐岩应该属于早二叠世紫松期的沉积,即为下二叠统鱼塘寨组的上段,因而矿区平掌组上段的地层及上石炭统缺失.并重新厘定了老厂矿区的地层层序.     

新疆北部二叠系特征及其与三叠系界线划分

目的对新疆准噶尔盆地南缘、吐哈盆地和三塘湖盆地的二叠系及其与三叠系界线的划分提供新的依据。方法在该区长期工作的基础上,参考前人地层划分成果及当地使用习惯,利用岩石地层、生物地层、火山岩同位素年龄、古地磁等方法进行综合分析,对三地区的二叠系进行了综合划分与对比。结果将新疆北部二叠系分别称下、中、上统,与中国南方及国际标准的3个统对应;中二叠统对应于瓜德鲁普统,地质时代为早二叠世(290~265 Ma),中、上二叠统界线在中二叠统塔尔郎组上部,上二叠统与三叠系界线在上二叠统锅底坑组内;中二叠统分布于准噶尔盆地中南部、吐哈盆地北部和三塘湖盆地南部。结论建议将大龙口、锅底坑、塔尔郎沟、照壁山剖面和跃进沟剖面分别作为北疆地区二叠系—三叠系标准剖面。     

Occurrences of Permian radiolarians in central and eastern Nei Mongol （Inner Mongolia） and their geological significance to the Northern China Orogen

The Zhesi (Jisu) Formation of the Middle Permian in Nei Mongol (Inner Mongolia) was commonly considered to be a shallow marine sequence. Here I report the radiolarians found in the argillite bed of that formation in Zhesi and Xilinhot areas. This fact indicates a deep marine sedimentary facies persisted during the Middle Permian, and suggests that the ocean between the North China Block and Siberian Craton was not closed until the Late Guadalupian. The suture of this two blocks is probably extends along the Linxi ophiolite belt, south of the Hegenshan ophiolite belt.     

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。     

塔里木盆地西北缘石炭-二叠系浊积岩的沉积特征及其构造意义

目的研究塔里木盆地西北缘晚石炭世晚期—中二叠世早期(逍遥—栖霞期)浊积岩沉积特征及其构造意义。方法对塔里木盆地西北缘上石炭统上部—中二叠统下部的浊积岩进行岩石、岩相和时空变化特点的分析。结果从晚石炭世晚期—早二叠世早期到中二叠世早期,浊积岩的沉积范围显著减小,沉积区域在向西南方向收缩的同时水体则进一步加深。结论这种沉积-构造特点反映当时南天山造山带内部处于强烈的构造活动状态,南天山造山带向塔里木地块的冲断推覆可以导致这种沉积-构造格局;从沉积学的角度提出南天山造山带在晚石炭世晚期—中二叠世早期可能处于碰撞造山作用的晚期阶段。     

Re-Os dating of Mo-bearing black shale of the Laoyaling deposit,Tongling, Anhui Province,China

Laoyaling is a typical stratiform deposit in the Tongling district and the molybdenum orebody is hosted by black shale of the Dalong Formation of the Upper Permian system. Eight black shale samples from the Laoyaling Mo orebody were dated by Re-Os technique using ICP-MS, which give an isochron age of 234.2±7.3 Ma with an initial 187Os/188Os ratio of 1.37±0.39. The apparent Re-Os age is a few million years younger than the depositional age of the Late Permian. The young isochron age may be caused by the later hydrothermal disturbance or mass fractionation during ICP-MS measurement. However, the obtained isochron age is close to the depositional age and far earlier than those of the Late Yanshanian intrusions. It suggests that the Mo ore of the Laoyaling deposit is sedimentary in origin and not related to the Late Yanshanian magmatism. Black shales of the Upper Permian are distributed widely in the Mid-Lower Yangtze region, our result is important for understanding the ore-forming processes in the regio     

Magnetostratigraphic study of Cretaceous depositional succession in the northern Kuqa Depression, Northwest China

Stratigraphic studies on the depositional succession in the Kuqa Depression can be traced back to as early as 1950s[1], however, there are still some disputes about chronostratigraphic division of the Bashenjiqike For- mation because of the paucity of fos…     

Permian palynofloras from Yongchang and Sunan of Gansu Province and their phytoprovincial characteristics

The Early Permian (Shansi + Lower Shihhotse Formations) palynofloras of Longshoushan are dominated by Cathaysian-Euramerican common forms, mainly composed of pteridophytic and pteridospermous spores. But up to the Lower Shihhotse Formation, gymnosperms greatly developed, and they possibly already dominated the vegetation in the Upper Shihhotse Formation; while in the late Late Permian, they indicate a strong colour of Subangara area. In other words, during the whole Permian, the Cathaysian flora had a history from prosperity to decline, and Subangara plants might have had a reverse tendency there.     

建南构造晚二叠世长兴期点礁和滩的高精度层序地层与储层评价

湖北利川的建南构造上二叠统长兴组长二段台地内的点礁和滩相沉积,为晚二叠世鄂西和川、渝东开阔台地内礁、滩的典型代表,其生长、发育受控于相对海平面变化.以薄片鉴定、钙镁分析和电测资料分析入手,将海平面变化与礁、滩体的沉积过程进行综合分析,可从长二段划分出2.5个四级沉积层序.在长二段礁、滩形成机理的系统研究基础上,指出礁、滩是在开阔台地上相对高的丘状隆起基底上发育起来的;白云岩化研究的结果,表明礁、滩的白云岩化和储层孔隙的发育与高位期的间歇性暴露与混合水作用有关.由于海平面变化的幅度较小及持续的时间较短,使得台内礁、滩的间歇性暴露时间较短,白云岩化强度不一,从而造成了礁、滩储层严重的非均质性.     

湖南二叠系的“南、北型”问题──兼谈上、下二叠统的界线

湖南二叠系“南、北型”是由早二叠世晚期华南东吴运动主幕所造成的,在华南各省具有普遍意义．湖南的当冲组仅相当于茅口组的中下部,龙潭煤系下段则相当于茅口组的上部,因而湖南二叠系的“南、北型”实质上是一个同时异相沉积的问题．上、下二叠统界线应划在龙潭组中、下老山段之间,这个界线才是与国际上流行的界线相一致的．     

内蒙古大青山煤田晚古生代沉积砾岩的物源分析

大青山煤田晚古生代沉积岩层中共有１４个砾岩层。通过岩矿鉴定、重矿物对比分析、砾度测量及不同成分砾石含量统计、Ｋ－Ａｒ同位素年龄分析及ＲＥＥ配分模式对比研究。证明晚石炭世早期及早二叠世早期砾岩主要砾石成分是石英砂岩,物源为下伏奥陶系石英砂岩;早二叠世中期砾岩主要砾石为石英岩砾石,夺为震旦纪石英岩;早二叠世晚期及晚二叠世初期砾岩的砾石成分主要为中酸性火山岩砾石,并含有一定量的太石界变质岩砾石,母岩分别     

云南省镇雄县马河矿区上二叠统龙潭组聚煤环境分析

滇东晚二叠世聚煤区,西靠川滇古陆,东临浅陆表海,自康滇古陆剥蚀区以东依次形成山麓冲积扇带、河流冲积平原带、三角洲平原及海滨平原带。云南省马河矿区上二叠统龙潭组镇雄段正处于冲积平原与滨海平原下三角洲的交替带,东部已处于滨海平原的海陆交互带及长兴期的浅海碳酸盐台地沉积环境,故成煤条件较差。     

A new species of Lepidopteris discovered from the Upper Permian of China with its stratigraphic and biologic implications

A new species Lepidopteris baodensis sp.nov.belonging to the family Peltaspermaceae and represented by two ultimate pinnae in the collection under study,was recently discovered at the Baijiagou of Baode,Shanxi,China,from the Upper Permian Sunjiagou Formation.The lower surface of the ultimate rachis,the midrib and secondary veins is covered with triangular,trapezoid,rounded,or ligulate subepidermal swellings,which show different natures from intercalary pinnules.Lepidopteris is one of typical elements of the Late Permian Euramerican flora.Since Schimper erected the genus Lepidopteris in 1869,the entire epidermal structure of subepidermal swellings had been unclear.The new species L.baodensis clearly showing the distinguished epidermal structure of subepidermal swellings,not only enlarges and supplements our knowledge in biology and taxonomy of Lepidopteris as well as the Upper Permian stratigraphy of China,but also provides an opportunity to understand the relationship between Euramerican floras and Cathaysian floras in paleoclimatic,paleoenvironmental and paleogeographic context.     

华南晚古生代Zoophycos时空分布及其控制因素

 基于对华南晚古生代3条剖面Zoophycos的精细解剖和前人资料分析,识别了螺旋形和舌形Zoophycos两种形态,揭示了华南晚古生代Zoophycos时空分布具有3个方面的特征：(1) 在时间上,Zoophycos广泛分布于早-中泥盆世(埃姆斯期-艾菲尔期)、密西西比亚纪(维宪期)及中二叠世(沃德期);(2) 在空间上,Zoophycos主要发育于黔东南、湘中南、桂东北一带;(3) 临滨至浅海下部是Zoophycos的主要产出环境。研究表明,华南晚古代Zoophycos的时空分布与大气含氧量(17%—24%),气候和温度(20—25℃),海水地球化学成分(方解石海Mg/Ca<2)以及生物灭绝事件等具有耦合关系。     

Permian tetrapods from the Sahara show climate-controlled endemism in Pangaea

New fossils from the Upper Permian Moradi Formation of northern Niger provide an insight into the faunas that inhabited low-latitude, xeric environments near the end of the Palaeozoic era (approximately 251 million years ago). We describe here two new temnospondyl amphibians, the cochleosaurid Nigerpeton ricqlesi gen. et sp. nov. and the stem edopoid Saharastega moradiensis gen. et sp. nov., as relicts of Carboniferous lineages that diverged 40-90 million years earlier. Coupled with a scarcity of therapsids, the new finds suggest that faunas from the poorly sampled xeric belt that straddled the Equator during the Permian period differed markedly from well-sampled faunas that dominated tropical-to-temperate zones to the north and south. Our results show that long-standing theories of Late Permian faunal homogeneity are probably oversimplified as the result of uneven latitudinal sampling.     

新疆北山晚古生代克拉通裂谷火山作用特征

新疆北山构造带克拉通裂谷活动期火山活动频繁,火山作用较强烈.区内晚古生代火山岩分布广泛,集中发育于下石炭统上部、上石炭统和下二叠统,与正常沉积岩呈断续间互层状产出.据岩石地层研究、火山岩产状及接触关系,划分为4个火山旋回,共9个火山喷溢韵律.在对区内火山岩地质特征、岩石类型、岩石化学和稀土元素地球化学特征研究基础上,探讨了火山岩的演化特点和形成环境.     

Origin, evolution and extinction of Cathaysia flora

Recent research results showed that the Cathaysia flora originated and developed from the global uniformLepidodendropsis flora of the Early Carboniferous, which had already become an independent flora in the early Late Carboniferous (Namurian B to C). The center of origin of the Cathaysia flora is restricted to the North China Plate. On the basis of the successional characteristics of the Cathaysia flora in different geological ages, it may be divided into seven evolutionary stages. The evolutionary trend of the Cathaysia flora, as a whole, was characterized by the gradual increase of the typical Cathaysian elements in the sequence from the early Late Carboniferous to the early Late Permian, which began to decline during the late Late Permian. The climatic differentiation, tectonic movement, oceanic circulation, palaeogeographical environment, extraterrestrial event and plant evolution caused the mass extinction of the Cathaysia flora on a large scale by the end of the Permian.     

西藏札达县姜叶玛的二叠系

本文首次列出西藏札达县姜叶玛二叠纪地层,古生物剖面,对该剖面进行了地层划分及时代讨论;建立了上二叠统姜叶玛组和下二叠统西兰塔组;简述了雅鲁藏布江沿线二叠系的分布特点、生物群特征、古地理概况以及地质意义。否定了雅鲁藏布江沿线二叠纪的灰岩块体“由北方远处推来的外来岩块或飞来峰”的说法。     

鄂尔多斯北部杭锦旗探区上古生界烃源岩评价

鄂尔多斯盆地北部杭锦旗探区上古生界烃源岩问题争议大。通过有机地球化学分析、盆地模拟等方法手段对研究区上古生界烃源岩展开研究。结果表明,上古生界发育石炭系、二叠系两套烃源岩,煤层是最好的烃源岩,泥岩为差烃源岩。煤层有机碳的质量分数最高,平均值为61.32%;有机质类型好,以Ⅲ型干酪根为主,属于生气型源岩;有机质成熟度为0.8%~1.3%,已经进入生气高峰阶段。烃源岩生气强度为(0.1~1.3)×109m3/km2,具备为研究区天然气成藏提供物质基础的条件。盆地模拟结果表明山西组总生气量大于太原组,是主要的烃源岩层系。烃源岩从侏罗纪末进入大规模生烃阶段,生烃高峰为早白垩世。研究区石炭系和二叠系煤层是上古生界天然气成藏的主要气源岩,天然气组分中甲烷含量变化、天然气侧向运移距离等证据进一步佐证了上述观点,突出了研究区上古生界烃源岩的原地性特征。