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obtained through extensive field-based mappingcoupled with detailed sedimentology and stratigraphyof key formations. The geological unitswithin the study area consist of the MaldonadoGroup (Playa Hermosa, Las Ventanas and SanCarlos formations), the Arroyo del SoldadoGroup (Yerbal, Polanco Limestones, BarrigaNegra and Cerro Espuelitas formations) and theArroyo de la Pedrera Group (Piedras de Afilarand Cerro Victoria formations). The MaldonadoGroup is characterized by a glacially influencedvolcanogenic-sedimentary sequence with icerafteddebris and dropstones in the Playa Hermosaand Las Ventanas formations. The Arroyodel Soldado Group is a mixed siliciclasticcarbonatesuccession, mainly represented by anintercalation of basal pink dolostones, bandedsiltstones, rhythmites of dolostone-limestone,iron formations, cherts and conglomerates. Carbonatesin the Polanco Limestones Formationare characterized by a negative δ 13 C excursionup to −3·26‰ PeeDeeBelemnite. The Arroyo dela Pedrera Group consists of quartz arenites andstromatolitic/oolitic dolostones. Preliminary dataindicate that the Precambrian–Cambrian couldbe contained within or at the base of this group.The entire succession is almost 6000 m thick,and contains a rich fossil assemblage composedof organic-walled microfossils and small shellyfauna, including the index fossil Cloudina riemkeae.The stratigraphic and chemostratigraphicfeatures are suggestive of a Gaskier age (ca580 Ma) for the basal glacial-related units. Inthis scenario, the results show the importance oflithostratigraphic, biostratigraphic andchemostratigraphic data of these Ediacaran unitsin the global correlation of terminal Proterozoicsedimentary rocks.2008040511华 南 贵 州 东 部 埃 迪 卡 拉 纪 至 寒 武 纪 过 渡 期 有机 碳 同 位 素 变 化 及 其 古 环 境 和 地 层 意 义 =Organic Carbon Isotopic Evolution during theEdiacaran-Cambrian Transition Interval in EasternGuizhou,South China: Paleoenvironmentaland Stratigraphic Implications. ( 英 文 ). YangXinglian; Zhu Maoyan; Guo Qingjun; ZhaoYuanlong. Acta Geologica Sinica, 2007, 81(2):194-203Secular variations of carbon isotopic compositionof organic carbon can be used in the studyof global environmental variation, the carboncycle, stratigraphic delimitation, and biologicalevolution, etc. Organic carbon isotopic analysisof the Nangao and Zhalagou sections in easternGuizhou reveals a negative excursion near thePrecambrian-Cambrian boundary that correlateswith a distinct carbonate carbon isotopic negativeexcursion at this boundary globally.2008040512前 寒 武 纪 非 叠 层 石 碳 酸 盐 岩 序 列 沉 积 特 征 及其 指 示 意 义 —— 以 北 京 延 庆 千 沟 剖 面 中 元 古代 高 于 庄 组 为 例 = Sedimentary Features andImplications for the Precambrian NonstromatoliticCarbonate Succession:A CaseStudy of the Mesoproterozoic GaoyuzhuangFormation at the Qiangou Section in YanqingCounty of Beijing. ( 英 文 ). Mei Mingxiang. ActaGeologica Sinica, 2008, 82(2): 295-309In the long Precambrian period, stromatoliticcarbonate successions were very common. However,the non-stromatolitic carbonate successionthat is marked by subtidal deposits shows asharp contrast to the stromatolitic carbonate succession.Both the non-stromatolitic and the stromatoliticcarbonate successions are importantclues for the further understanding of the evolvingcarbonate world of the Precambrian. TheMesoproterozoic Gaoyuzhuang Formation at theQiangou section in northwestern suburb of Beijingis a set of more than 1000 m-thick carbonatestrata that can be divided into four members (orsubformation), in which a non-stromatolitic carbonatesuccession marked by the scarcity ofstromatolites makes up the third member of theformation.古 生 界2008040513关 于 下 寒 武 统 的 阶 划 分 问 题 = To the problemof stage subdivision of the Lower Cambrian. ( 英文 ). Rozanov A YU; Khomentovsky V V.Stratigraphy and Geological Correlation, 2008,16(1): 1-19It was a serious mistake when subdivisionstratotypes had been disposed of in practice ofconstructing the General stratigraphic scale, becausethey cannot be substituted by the boundarystratotypes. A subdivision stratotype and respectiveGSSP are complementary parts characterizingany stratigraphic unit. The best candidatesfor stage stratotypes of the Lower Cambrian arecertainly sections of the Lena-Aldan region inthe Siberian platform, which have been studiedin detail during many years, are well exposed,and contain abundant and diverse fossils, beinginsignificantly disturbed by tectonic dislocations.Nomenclature, stage and boundary stratotypes ofthe Siberian standard can be successfully usedtherefore for stratigraphic subdivision of theLower Cambrian.2008040514俄 罗 斯 西 伯 利 亚 地 台 东 南 周 边 中 、 上 泥 盆 统= The Middle and Upper Devonian in southeasternflank of the Siberian platform (SouthernVerkhoyansk Region, Sette-Daban Mountain154