Global Distribution of Permian Conulariids and Palaeobiogeographical Implications

Previously, minimal work has been carried out on conulariids due to their rare occurrences and resultant biostratigraphical limitations. The palaeobiogeographical distribution of Permian conulariids suggests that they have a marked preference for cold to cool-water regions, that they are significant indicators for migration patterns, and that they can potentially provide information on the palaeogeographical configuration and movement of terranes. Permian conulariids are found in Australia, India, New Zealand, Pakistan, Iran, Afghanistan, Kashmir, China, Japan, Russia, Germany, Canada, United States of America, and Bolivia. The diversity of Permian conulariids is markedly higher in the polar regions than in the palaeoequatorial region.

Permian conulariid genera include Notoconularia Thomas 1969, Gondaconularia Waterhouse 1986, Cheliconularia Waterhouse 1986, Neoconularia Sugiyama 1942, Calloconularia Sinclair 1952, Diconularia Sinclair 1952, Paraconularia Sinclair 1940, Mesoconularia Boucek 1939 and Conularia Sowerby 1821. This paper describes two new species of conulariids: Diconularia meadepeakensis sp. nov. from the Phosphoria Formation (Guadalupian), Idaho, USA and Paraconularia kazanensis sp. nov. from the Sokian Horizon (?Roadian), Volga Region, Russia.     

华北板块北缘中二叠统于家北沟组植物化石及其大地构造意义

通过对内蒙古赤峰市广兴源乡于家北沟组模式剖面植物化石和安山质晶屑岩屑凝灰岩锆石U-Pb同位素年代学的研究,结合动物化石的分析,确认于家北沟组地质时代为中二叠世。于家北沟组植物化石以Gigantonoclea hallei Asama、Fascipteris sinensis Stockm. et Math.、Pecopteris taiyuanensis Halle、Pterophyllum daihoense Kaw.等众多华夏植物群典型分子为特征,属于典型的华夏植物群。目前,在中二叠世植物群中,从未发现有华夏和安加拉两大植物群的混生现象,这一事实进一步表明,中二叠世横亘于华北板块和佳蒙地块之间的古亚洲洋尚未闭合,在植物地理分布上起着重要的阻隔作用。     

Interregional Correlation of the Permian Continental and Marine Deposits of Northeastern Russia,Southern Far East,Siberia, and Pechora Cisurals

Correlation of the Permian continental and marine deposits of Northeastern Russia, the southern Far East, Siberia, and the Pechora Сisurals is carried out. A consistent zonal succession of brachiopods, marine bivalves, and ammonoids is revealed and linked with the macroflora in the boundary deposits of the Cisuralian/Biarmian Series of the Boreal Superrealm. As a result, analogues of the Solikamian, Irenskii, Filippovskii, and Saraninian Horizons of the Kungurian Stage are established in the main coal basins and marine sequences of Northeastern Russia and the southern Far East. The correlative floristic horizon, stretching from the east of the East European Platform to the Pechora Cisurals, Pai-Khoy, Siberia, the Kuznetsk Basin, Northeastern Russia, and the southern Far East is established. The unity of the Sheshmian–Kazanian nonmarine floral assemblages and nonmarine bivalves, which correspond to the marine biota of Kazanian age, and their distinction from Kungurian assemblages are established. The Kungurian–Kazanian boundary is traced in marine and continental deposits within the entire Boreal Superrealm. The invalidity of the Ufimian Stage is established. The Kazanian Stage corresponds to the Roadian Stage of the International Chronostratigraphic Chart; however, the lower boundary of the Kazanian Stage is not defined precisely and can be conventionally considered isochronous to the boundary of the Roadian Stage.     

鄂西新滩二叠纪腕足类的群落演变与环境关系

系统研究了湖北省西部新滩剖面亚丁斯克阶至长兴阶的腕足动物群落演替过程.通过研究区与华南地区及特提斯区域进行比对分析,结合前人对碳、氧同位素的研究结果,分析了二叠纪腕足类群落演替的规律和区域差异.结果表明:除二叠纪末的灭绝事件,在乌拉尔统与瓜德鲁普统界限附近及乐平统中共识别出两次腕足类种群的显著分异度变化,且其演替时间都...     

湖南嘉禾大窝岭剖面晚二叠世吴家坪期-长兴期之交长英质火山作用记录

在华南地区,中-晚二叠世之交和二叠纪-三叠纪之交的火山作用已成为地学研究的热点. 相比较,地学界对晚二叠世内部的火山活动关注较少,以至对华南地区晚二叠世内部火山作用的喷发特征认识不够. 湖南省嘉禾地区大窝岭剖面大隆组中下部,即吴家坪阶-长兴阶界线附近沉积了3层粘土岩,自下而上分别为HD08、HD12和HD20.对这3层粘土岩进行全岩地球化学,锆石U?Pb年代学、微量元素和Lu?Hf同位素测试工作表明,这些粘土岩源自蚀变的火山灰,代表吴家坪阶-长兴阶之交的三期火山作用.全岩和锆石微量元素特征显示火山灰来源于流纹质或流纹英安质火山作用,具有钙碱系列的亲属性,形成于汇聚大陆边缘的后碰撞构造环境. 其中,HD08和HD20的ε_Hf（t）值为-6.4~7.1,范围变化较大,岩浆源于峨眉山/新元古代新生地壳物质和古老地壳物质的混合;HD12的ε_Hf（t）值为-12.0~-3.5,岩浆主要来源于古老地壳物质.这3层火山灰层的发现丰富了华南地区乐平统地层中火山作用的记录,综合前人研究成果,进一步证实了华南地块周边地区在晚二叠世中期发生强烈的、与Pangea超大陆汇聚有关的长英质火山作用.      

二叠系全球界线层型和点位(GSSP)研究进展

新的二叠纪年代地层系统为国际二叠系分会通过并正式纳入“国际地层表”后,已有5个GSSP得到正式批准,它们分别是阿瑟尔阶(二叠系)、吴家坪阶、卡匹敦阶、沃德阶和罗德阶的底界。长兴阶底界的GSSP提案在国际二叠系分会投票中,以94 %赞成票通过,并交国际地层委员会进行投票表决。国际二叠系分会最近的主要工作重点将是早二叠世乌拉尔统内空谷阶底界、亚丁斯克阶底界和萨克马尔阶底界的确定工作,由B.I.Chuvashov领导的界线工作组正在对俄罗斯乌拉尔南部的界线剖面进行工作。国际二叠系分会力争在2 0 0 6年底前完成投票工作,并使二叠纪的地层研究全面转入国际间对比等层型后研究     

Stratigraphic and palaeoenvironmental framework of the Early Permian sequence in the Salt Range, Pakistan

The Early Permian Gondwana regime succession of the Nilawahan Group is exposed only in the Salt Range of Pakistan. After a prolonged episode of non-deposition that spanned much of the Palaeozoic, the 350?m thick predominantly clastic sequence of the Nilawahan Group records a late glacial and post-glacial episode in which a range of glacio-fluvial, marine and fluvial environments evolved and accumulated. The Early Permian succession of the Salt Range has been classified into four formations, which together indicates a changing climatic regime during the Early Permian in the Salt Range region. The lower-most, Tobra Formation unconformably overlies a Cambrian sequence and is composed of tillite, diamictite and fresh water facies, which contain a floral assemblage (Gangamopteris and Glossopteris) that confirms an Asselian age. The Tobra Formation is overlain by marginal marine deposits of the Dandot Formation (Sakmarian), which contain an abundant brachiopods assemblage (Eurydesma and Conularia). Accumulation of the Dandot Formation was terminated by a regional sea-level fall and a change to the deposition of the fluvial deposits of the Warchha Sandstone (Artinskian). The Warchha Sandstone was deposited by high sinuosity meandering, avulsion prone river with well developed floodplains. This episode of fluvial sedimentation was terminated by a widespread marine transgression, as represented by the abrupt upward transition to the overlying shallow marine Sardhai Formation (Kungurian). The Early Permian Gondwana sequence represented by the Nilawahan Group is capped by predominantly shallow shelf carbonate deposits of the Tethyan realm. The sedimentologic and stratigraphic relationship of these four lithostratigraphic units in the Salt Range reveals a complex stratigraphic history for the Early Permian, which is mainly controlled by eustatic sea-level change due to climatic variation associated with climatic amelioration at the end of the major Gondwana glacial episode, and the gradual regional northward drift to a lower latitude of the Indian plate.     

Spatial and Temporal Distribution of the Cryptospirifer Fauna(Middle Permian Brachiopods) in the Tethyan Realm and Its Paleogeographic Implications

The middle Permian Cryptospirifer fauna （brachiopod） has hitherto been found in more than 30 localities in the Yangtze Platform, South China. Examination of data from various localities shows that it occurs stratigraphically in three intervals in the range from the upper Kungurian to Wordian. In the Baoshan block in western Yunnan the fauna occurs in the basal part of the Daaozi Formation and is of possibly an early Wordian age. Outside China the Cryptospirifer fauna has been reported from central and northwest Iran and central Turkey, where the fauna may have an age around the Wordian／Capitanian boundary. Rapid global warming since the late Early Permian and possession of other suitable environmental factors such as proper substrate, clastic input and water depth enabled the Gondwana-derived Baoshan Block and related tectono-stratigraphic units in Iran and Turkey to host the Cryptospirifer fauna, a fauna evolved in the Yangtze Platform that is a type area of the Cathaysian province.     

鄂西—渝东晚二叠世长兴期古地理格局及生物礁展布的再认识*

通过地层、古生物、地震相、地震属性分析,笔者发现了利川和石柱地区存在晚二叠世长兴期台内盆地的证据,并分别命名为利川台内盆地和石柱台内盆地。基于上述证据和前人研究成果,对鄂西—渝东地区的古地理格局及生物礁展布提出了新的认识:利川台内盆地、石柱台内盆地及鄂西盆地共同控制了鄂西—渝东地区晚二叠世长兴期台盆相间的古地理格局,生物礁主要沿这3个盆地边缘呈带状展布;鄂西盆地在长兴组一段沉积时期形成,该台地边缘坡度较陡,发育陡坡型生物礁;利川台内盆地和石柱台内盆地分别形成于长兴组一段和组二段沉积时期,其台地边缘坡度较缓,分别发育长一期和长二期缓坡型生物礁。与缓坡型生物礁相比,陡坡型生物礁横向及纵向发育规模更大。     

长江源各拉丹冬地区晚二叠世乌丽群类生物组合

长江源各拉丹冬地区二叠系乌丽群中的晚二叠世类化石 ,可分为两个组合 ,产于乌丽群下部那益雄组的Palaeofusulina parafusiformis- N anlingella simplex组合 ,产于乌丽群上部拉卜查日组的 Gallowayinella meitienen-sis- Palaeofusulina sinensis组合 ,这两个类化石组合属种分异度低 ,丰度高。该生物群属于特提斯动物群 ,在羌塘盆地及华南地区具有广泛的区域对比性。各拉丹冬及其邻近地区的二叠纪类生物群均为暖温型 ,属华夏特提斯区的分子     

吉林延边地区汪清县大兴沟早二叠世华夏植物群的发现及其地质意义

吉林省延边地区汪清县大兴沟镇和盛村附近和盛组中首次采获大童植物化石:Lepidophylloides sp.,Stigmaria ficoides(Stemb.)Brongn.,Trizygia oblongifolium(Germ.et Kaulf.)Asama,Cal-amites cistii Brongn.,C...     

The Cimmerian Orogeny in northern Iran: tectono-stratigraphic evidence from the foreland

From the Permian onwards, the Gondwana-derived Iran Plate drifted northward to collide with Eurasia in the Late Triassic, thereby closing the Palaeotethys. This Eo-Cimmerian Orogeny formed the Cimmeride fold-and-thrust belt. The Upper Triassic–Middle Jurassic Shemshak Group of northern Iran is commonly regarded as the Cimmerian foreland molasse. However, our tectono-stratigraphic analysis of the Shemshak Group resulted in a revised and precisely dated model for the Triassic–Jurassic geodynamic evolution of the Iran Plate: initial Cimmerian collision started in the Carnian with subsequent Late Triassic synorogenic peripheral foreland deposition (flysch, lower Shemshak Group). Subduction shifted south in the Norian (onset of Neotethys subduction below Iran) and slab break-off around the Triassic–Jurassic boundary caused rapid uplift of the Cimmerides followed by Liassic post-orogenic molasse (middle Shemshak Group). During the Toarcian–Aalenian (upper Shemshak Group), Neotethys back-arc rifting formed a deep-marine basin, which developed into the oceanic South Caspian Basin during the Late Bajocian–Late Jurassic.     

西南地区二叠纪层序地层及海平面变化

西南地区二叠系可划分为２个二级层序、１１个三级层序,它们代表１１次三级海平面升降旋回,其中有６次可与欧美地区二叠纪海平面变化相对比,它们是伦纳德（Ｌｅｏｎａｒｄｉａｎ）早期、瓜达卢普（Ｇｕａｄａｌｕｐｉａｎ）早期、瓜达卢普（Ｇｕａｄａｌｕｐｉａｎ）晚期、卡赞（Ｋａｚａｎｉａｎ）早期、鞑靼（Ｔａｔａｒｉａｎ）早期和鞑靼（Ｔａｔａｒｉａｎ）晚期的海平面旋回。研究表明,该区二叠纪相对海平面变化作为全球海平面变化和同沉积构造活动相互作用的产物,它与欧美地区乃至联合古陆发展具反向效应,即具有以海侵型碳酸盐沉积序列为典型的主体海平面上升的特点。作者认为显生宙全球海平面旋回曲线的二叠纪部分总体具有两种类型或分支：其一是以海侵型碳酸盐沉积序列为主的反映海平面主体上升的特提斯型或华南型;其二是以海陆过渡—陆相海退沉积序列为主的揭示海平面主体下降的经典型或欧美型。作者强调,全球二叠纪海侵型全球海平面旋回曲线应以西南地区为代表。     

贵州紫云晚二叠世-早三叠世初火山作用与生物礁的沉积演化

晚二叠世长兴期是华南地区重要的成礁期,也是火山事件频发的一个时期。生物礁是一种对海洋环境十分敏感的生态系,晚二叠世的火山作用势必影响到当时生物礁的生长和沉积相的演化。然而,前人有关晚二叠世火山事件的研究主要集中在二叠系与三叠系界线附近,而对整个长兴期生物礁的演化与火山事件关系的研究则较少。选择贵州紫云的台地边缘礁为研究对象,通过大量磁化率的测试,分析整个晚二叠世生物礁的沉积演化与火山作用的关系。分析结果显示,长兴早期和末期岩石的磁化率值明显偏高,反映较强的火山活动。在这两个时期,造架生物相对不发育。长兴中期,岩石的磁化率值相较于长兴早期和长兴晚期总体偏低,表明火山活动相对较弱,导致生物礁的快速生长。但长兴中期生物礁灰岩中夹有几层生物碎屑灰岩,其磁化率值有小幅度的升高,说明短时期小规模的火山作用虽然导致了生物礁生长的暂时中断,但礁相动荡的环境使得火山灰中细小的铁磁性物质难以沉积下来。研究发现,尽管早三叠世早期泥岩具有高的磁化率值,但泥质岩中多层火山黏土具有异常高的磁化率值,火山灰物质对磁化率大小的影响远远超过陆源物质的贡献。     

Prevailing anoxia in the Kungurian (Permian) of South China: Possible response to divergent climate trends between the tropics and Gondwana

The Kungurian ocean-climate system has received little attention, but a new compilation of geochemical and paleoclimatic proxies suggest more complex climate dynamics during the Late Paleozoic icehouse–greenhouse transition than previously considered. Here, integrated carbon isotope stratigraphical, sedimentological, and geochemical data across two Early–Middle Permian successions in the Youjiang Basin, South China, is presented. These proxies indicate widespread anoxia below or near the water-sediment interface in South China during the Kungurian. High primary productivity, high sedimentation rate, and a relative sea-level rise are here proposed as being responsible for this process in the late Kungurian, but cannot account for the remaining anoxia at cycle boundaries. We put forward a hypothesis that divergent climate trends between the tropics and Gondwana might have played an important role in ocean stagnation and prevailing O₂-deficient conditions in and probably outside South China during the Kungurian. The termination of anoxia in this region during the latest Kungurian is attributed to an intensification of oceanic circulation, a rise in atmospheric pO₂ concentrations, a sea-level drop, depressed primary productivity, and low sedimentation rates. This study calls for further high-resolution sedimentological and geochemical investigations on the paleotropics outside South China, in order to elucidate the icehouse-greenhouse transition at the global scale.     

Late Paleozoic tectonic -magmatic evolution history of the northeastern ChinaSCIEI北大核心CSCD

Northeastern China is suited in the eastern part of the Central Asian Orogenic Belt, and it is mainly composed of Erguna Massif, Xing'an Massif, Songnen-Zhangguangcai Range Massif, Jiamusi Massif, and Nadanhada Terrane. The Late Paleozoic magmatism was relatively intense accompanied with multiple stages of amalgamation in several microcontinents, therefore these magmatic products are an important media in recording the Late Paleozoic tectonic evolution history of the northeastern China. According to the petrological, geochronological, and geochemical characteristics of Late Paleozoic igneous rocks in the northeastern China, we found that the Late Paleozoic magmatism was based on Carboniferous -Permian igneous rocks. The Early Carboniferous magmatic products are gabbro, diorite and granite, the Late Carboniferous magmatic products are mainly composed of granitoids with minor gabbro, and the Permian magmatic products are mainly granitoids. Meanwhile, these Late Paleozoic igneous rocks mostly exhibit typical arc characteristics. In addition, the Late Paleozoic igneous rocks in eastern Jilin and Heilongjiang provinces are mainly Permian granitoids with minor gabbro, and these Permian igneous rocks show typical arc characteristics. Combined with petrological, geochronological, geochemical and isotopic characteristics, we suggest that the Late Paleozoic igneous rocks in the Great Xing'an Range and eastern Jilin and Heilongjiang provinces underwent different magmatic evolution history, and the microcontinents in NE China had different crustal growth history.     

古亚洲洋和古特提斯洋的闭合时代——论二叠纪末生物灭绝事件的构造起因

通过对比分析华南地块和基墨里大陆（包括保山、缅泰和羌塘地块）间、华北和西伯利亚地块间的古纬度和纬度运移量,分别确定了古特提斯洋和古亚洲洋的闭合时代。结果表明：（1）基墨里大陆东部的保山地块与华南地块于晚二叠世碰撞,然后继续和华南地块、缅泰地块、羌塘地块一起向北漂移,直到晚三叠世,即在云南三江地区,古特提斯洋的闭合时代为晚二叠世晚期; （2）早二叠世西伯利亚地块开始快速向南漂移,并于二叠纪末期（～250 Ma）和华北地块发生碰撞,即位于两地块间古亚洲洋最终闭合时代为二叠纪末;（3）峨眉山和西伯利亚两个大火成岩省的形成时代和大洋的闭合时代吻合,而大火成岩省在时间上又与全球生物灭绝事件吻合,进而推断二叠纪末的生物灭绝事件可能与古亚洲洋和古特提斯洋的闭合密切相关。     

Progress in the Gondwanan Carboniferous–Permian palynology and correlation of the Nilawahan Group of the Salt Range,Pakistan: A brief review

This paper comprises of two sections. The first section describes challenges in the Carboniferous–Permian Gondwanan stratigraphic palynology, and progress in techniques such as presence of the ‘rare-marine intervals’, and ‘radiometric dating’ in some Gondwanan successions, e.g., South Africa, Australia and South America, as tools to confidently calibrate these palynozones. The second section describes developments in the palynological work on the Carboniferous–Permian Nilawahan Group of the Salt Range, Pakistan, and summarises their correlation with the coeval succession of the Gondwana continents and with the Russian/International stages.     

Characteristics of Albaillella （ Albaillellarian ,Radiolarian） Fauna from Guadalupian to Lopingian Series in Permian, South China

On the basis of establishment of radiolarian biostratigraphy and conodont biostratigraphy,a radiolarian Albaillella fauna in the transitional environment from Guadalupian to Lopingian Series in Permian was found at a pelagic chert section in southeast Guangxi, South China. Radiolarian Albaillella is one of the most sensitive biology to the transitional environment. The Albaillella fauna shows an ecological evolutionary process from Guadalupian to Lopingian: declined stage-recovery stage-flourishing stage. The study of characteristics of the Albaillella fauna in the transitional environment may provide more information, not only for the subdivision and correlation of a high-resolution biostratigraphy, but also for influence of radiolarian Albaillella fauna on the pre-Lopingian mass extinction.     

Global correlation of basal Triassic layers in the light of the first carbon isotope data on the Permian-Triassic boundary in Northeast Asia

This paper is dedicated to the global correlation of the marine Permian-Triassic boundary layers based on some published and original data on the δ¹³C_org and δ¹³C_carb values obtained for the section along the Suol Creek (Setorym River, southern Verkhoyansk region). The section includes six carbon-isotope intervals readily distinguished in the corresponding curves obtained for several Permian and Triassic reference sections in Eurasia and North America including palleontologically well substantiated sections of central Iran, Kashmir, and South China. This provides grounds for assuming the Permian-Triassic boundary’s position in the Suol Creek section as being close to the carbon-isotope minimum of Interval IV. In the light of new data, the upper part of the Upper Permian Changhsingian Stage in Siberia is proposed to correspond in range to the Otoceras concavum range zone, and the lower substage of the Lower Triassic Induan Stage, to the Tompophiceras pascoei and Wordieoceras decipiens zones. The Otoceras concavum Zone of the Verkhoyansk region in its new understanding is likely correlative with the upper Changhsingian Hypophiceras triviale Zone of Greenland. Carbon-isotope intervals II, III, IV, and V defined in the Permian-Triassic boundary layers of the Verkhoyansk region, which are traceable in several reference sections of Eurasia and North America, evidently coincide with the period of some intensification of the volcanic activity in the initial late Changhsingian and with the first phases of extensive eruption of Siberian trappes in the terminal Changhsingian and initial Induan ages. New data imply the probable survival of some ammonoid species from the superfamily Otoceratoidea after the mass extinction of organisms in the terminal Permian Epoch.