放射虫Cecrops septemporatus带在世界各地的瓦兰今阶广泛分布,中国最早在上世纪八、九十年代发现于藏南日喀则地区雅鲁藏布蛇绿岩南侧的下鲁硅岩中.本文对相关样品(80-141)进行再研究,描述放射虫18属23种,包括3个新种.该放射虫组合具有 Aurissaturnalis variabilis variabilis(Squinabol),Thanarla elegantissima(Cita),Pantanellium corriganensis Pessagno等重要带化石,可与江孜地区混杂堆积和泽当地区蛇绿混杂岩的硅质岩中发现的相关组合及国际同类放射虫生物带进行比较,为全面认识该时期全球放射虫组合面貌及区域对比提供新的证据.

南海西沙群岛西科1井374.95-1 257.5 m井段发现石珊瑚化石19属,分别为Acropora,Antillophyllia,Astreopora,Caryophyllia,Coenangia,Cricocyathus,Cyphastrea,Di ploastrea,Enallopsammia,Favia,Favites,Fungia,Goniastrea,Leptastrea,Meandrina,Monti pora,Phyllangia,Porites和Turbinaria等,主要分布于黄流组二段和一段顶部、梅山组二段上部和一段以及三亚组二段.其中Antillophyllia分布于渐新世到中新世,Cricocyathus的分布时代为始新世至中新世,说明含上述2属珊瑚的地层时代不晚于中新世.综合有孔虫、大型底栖钙藻和钙质超微化石等的时代划分结果,推断374.95-1 257.5 m井段的时代属于中新世.对Cricoc yathus sp.,Antillophyllia sp.和Phyllangia sp.等单体珊瑚和群体珊瑚Goniastrea sp.的主要特征进行了描述.

作为错时相沉积之一的巨鲕灰岩在我国华南早三叠世地层中广泛出现,在寒武纪之后本已消失的这种沉积类型为什么会在早三叠世又重新出现？在四川江油渔洞子下三叠统飞仙关组鲕粒灰岩的底部,产有一套巨鲕灰岩,通过高倍显微镜及扫描电镜的深入研究,首次发现在巨鲕灰岩的鲕粒和围岩中充满丰富的疑似底栖蓝细菌、疑似颗粒状浮游蓝细菌及其他超微化石.根据这些疑似底栖蓝细菌的结构和构造特点,可以划分出下列几种类型:疑似蛛网状蓝细菌,疑似微球状蓝细菌,疑似网格状蓝细菌,疑似蠕虫状蓝细菌,疑似直管状蓝细菌,疑似链状蓝细菌,疑似花瓣状蓝细菌和Renalsis,疑似颗粒状浮游蓝细菌(主要有两种类型:简单的椭球粒和螺旋状球粒).超微化石包括钙球和铃铛形超微化石.疑似底栖和浮游蓝细菌及其他超微生物的大量繁盛,是二叠纪-三叠纪之交海洋生态环境恶化、海洋底栖动物大灭绝所产生的后果.这一发现不仅使我们在微观世界和超微世界里重新认识巨鲕灰岩的成因,它是生物和沉积两种主要因素共同作用的结果,从而对巨鲕灰岩的时代分布做出了很好的解释;同时,也可以帮助我们重塑当时该地区的海洋古生态系统.

我国华南二叠纪-三叠纪之交的地层中,微生物岩发育,其中所发现的蓝细菌以结构、构造比较简单的微球状蓝细菌为主.四川广安谢家槽剖面下三叠统夜郎组底部产有一套厚约20 m的凝块岩,通过对凝块岩薄片的显微镜照片观察,发现其中产有丰富的、保存精美的疑似的蓝细菌化石,它们清楚地展现了比此前所报道的蓝细菌更为复杂的内部结构、构造.根据其特点,可以分辨出四种主要类型:疑似的花冠状蓝细菌,疑似的蛛网状蓝细菌,疑似的嫩芽状蓝细菌和疑似的似管状蓝细菌,文中对它们进行了详细描述.另外,在研究的凝块岩薄片中,还发现了有些黑色的条带,这些条带并没有覆盖整个凝块岩,只是覆盖一部分,其中蓝细菌的结构、构造与条带外的微生物岩中的蓝细菌有着很大区别,条带中的黑色物质远比条带外的多,围绕这些黑色物质的丝状体呈网孔状,而条带外的丝状体则呈长条形或椭球状.这些黑色的条带很可能是原始的蓝细菌生物膜,文中称之为疑似的蓝细菌生物膜,这也是早三叠世蓝细菌生物膜的首次报道.对蓝细菌生物膜的进一步研究,可以帮助我们了解蓝细菌的生长过程以及生物膜在微生物岩形成中的作用.

Abundant Early-Middle Triassic foraminiferal fossils were collected from the limestones of the Xiejiacao section,Guan'an,Sichuan,China of which 34 species in 12 genera have been identified and described systematically.According to the distribution characteristics of the foraminiferal assemblages on this section,4 foraminiferal assemblage zones are recognized from the bottom up as follows:(1) Rectocornuspira kalhori-Cornuspira mahajeri Zone;(2) Glomospirella vulgaris-Arenovidalina chialingchiangensis Zone;(3) Meandrospira pusilla-Glomospirella irregulariformis Zone;(4) Glomospira sinensis Arenovidalina amylovoluta Zone.These foraminiferal zones provide very important fossil evidence for the precise biostratigraphical sub-division and correlation of the marine Triassic strata in this region.

The disaster event of marine ecological environments at the end-Permian resulted in mass extinction of marine benthic fauna and the explosion of Early Triassic cyanobacteria mainly found from microbialite.The abundant doubtful cyanobacteria are first discovered in the giant oolitic limestone of the lower part of the Feixianguan Formation.Their types and structures are very different from cyanobacteria found in the microbialite at the bottom of the Feixianguan Formation reported before.The gathering of doubtful cyanobacteria in the giant ooids and host rocks implies that the formation of the giant oolitic limestone was closely related to the doubtful cyanobacterial activities.In this case it is similar to the formation of microbialite found at the bottom of the Feixianguan Formation.It can be inferred that two episodes of Early Triassic doubtful cyanobacterial explosions occurred in this region and provide a clue that there were two events of marine ecological environmental deteriorations at least.However,the Early Triassic explosions of cyanobacteria are of benefit to the improvement of marine ecological environments and biotic recovery.Therefore,it is significant for the very late Early Triassic and the Middle Triassic overall biotic recovery and radiation.

The abundant nannofossils including "doubtful" nannobacteria and "doubtful" coccoid plankton cyanobacteria are first discovered in the giant oolitic limestone of the lower Feixianguan Formation at the Yudongzi section,Jiangyou,Sichuan,SW China.The discovery indicates that the formation of the giant oolitic limestone was possibly related to the activities of "doubtful" coccoid plankton cyanobacteria and benthic cyanobacteria.This paper also suggess the mechanism of non-organic calcites formation.As the main members in the marine palaeoecological system in the Early Triassic of this region,the "doubtful" benthic cyanobacteria and plankton coccoid cyanobacteria built a simple trophic web.Their expansion was due to the deterioration of marine environments,which also caused the extinction of benthic fauna occurred in this period.

This paper reports the first discovery of Spirorbis phlyctaenain China which was found in the microbialite at the bottom of the Lower Triassic Feixianguan Formation(Greisbachian)of the Yudongzi Section of Jiangyou,Sichuan Province.It offers information about the composition,structure and paleoecology of the Early Triassic biologic community associated with the benthic microbial community.The occurrence of serpulid spirorbis belonging to annelida in the zone of conodont Hindeodus parvus further inplies that annelida is one of pioneers of Early Triassic biologic recovery.In comparison with S.phlyctaenafound in Siusi Member of the Werfen Formation from northern Italy,the S.phlyctaenaat the bottom of the Lower Triassic Feixianguan Formation is nearly same in size.The Lilliput efficiency happens in brachiopod Lingunellabut not in ser pulid spirorbis.

17 ichnogenera are described as Arenicolites, Bifungites,Chondrites,Didymaulichnus,Isopodichnus,?Monocraterion,Palaeophycus,Phycodes, Planolites, Psammichnites, Skolithos, Taenidium,Teichichnus,Thalassinoides,Treptichnus,Uchirites and Star-like trace fossils.They are assigned to the Cruzianaichnofacies reflecting shallow water environments with soft substrates. Some special taxa are known to have occurred in the storm-generated sediments. Skolithos are mainly yielded from the storm layers and Planolites and Palaeophycus from warning storm deposition layers respectively.The opportunistic taxa such as Chondrtes, Treptichnus gathering in stripped limestones are indicative to dysaerobic environments.This paper also probes into the relationship between the spatial and anachronistic distribution of the trace fossils in the Early Triassic and ocean biotic recovery after the Permian/Triassic mass extinction.

A dolomite unit near the Permian-Triassic boundary has long been used as the boundary marker in northwestern Sichuan but no biostratigraphically diagnostic fossils have been found in this units.Here we report the discovery of the conodont Hindeodus parvus and foraminifer disaster species from a microbiate bed in the dolomite unit above Permian coral beds at the Yudongzi section in Jiangyou of Sichuan Province.This discovery allows us to determinate the Permian-Triassic boundary in northwestern Sichuan and to understand the ecological and environmental changes across the boundary.We also present a detailed sedimentological analysis of the uppermost Changxing Formation and the lower-middle Feixianguan Formation

Various anachronistic sediments such as flat-pebble conglomerates , vermicular limestones , stromatolites , microlaminate limestone , thin-bedded limestone , ribbon limestone , and horizontal trace fossils occur abundantly in the Lower Triassic Yelang and Jialingjiang formations at the Xiejiacao Section of Guangan , Sichuan Province.The relative abundance of these anachronistic sediments decreases section , and they are restricted to the high-stress environments in the late Early Triassic.The temporal and spatial distribution of the anachronistic sediments reflects the recovery history of the ocean and paleoecologic systems following the end-Permian mass extinction..

According to our study of their grains,textures and structures,the limestones of the Early Triassic Yelang and Jialingjiang formations in the Xiejiacao Section of Guangan,Sichuan can be divided into five main microfacies types and fifteen second order ones.On this basis too,their sedimentary environments can be assigned to:Ⅰ.platform margin;Ⅱ.open marine platform;Ⅲ.restricted marine platform;Ⅳ.platform evaporites.The sedimentary environments swiftly changed into platform evaporites from the end phase of the Early Triassic Jialingjiang Formation into the succeeding Middle Triassic Leikoupo Formation.In general the changes of depositional environments through the Lower and into the Middle Triassic reflect a continuing regressive sequence in the region.

This paper discusses the geological contexts of the Guanling fauna,which occurs in the lower Carnian(Upper Triassic) Wayao Formation(=Xiaowa Formation) in the Guanling area of Guizhou Province,southwestern China,and contains a large number of exceptionally preserved marine fossils,including marine reptiles,crinoids,ammonoids,bivalves,brachiopods,and conodonts.The conclusions are as follows.1) The lithological and faunal characters,especially taphonimic features,indicate that the Guanling fauna most likely lived in a rift valley environment.The mass mortality of the fauna may have been caused by a seismic disaster according to Wang Shang-yan(2006).2) The Kueichousaurus hui fauna,which is characterized marine reptiles and associated fishes,ammonoids,bivalves,and conodonts,from the lower Carnian in Xingyi-Anlong-Luoping districts,is herein correlated with the Guanling fauna based on conodonts,ammonoids and the Halobia-assemblage.3) The spatial distribution of the Guanling fauna and the Kueichousaurus hui fauna follow a "S-shaped zone",which is interpreted as a tectonic belt situated between the Yangtze Platform and the Napanjiang Basin in the Triassic Period.This "S-shaped zone" was a fault-bounded depression in the Middle Triassic,became a rift valley in the early Carnian,and turned into a bay during the late Carnian-early Norian ages.