中国早石炭世早期阶和亚阶的划分与对比

简要回顾了中国早石炭世早期地层“阶”和“亚阶”划分的历史沿革,阐述了划分的基本原则,即在全球性或大区域性关键地质事件和生物进化事件研究的基础上,将“阶”和“亚阶”的底界应置于地质事件之后某一或某些主导生物门类谱系演化的分支点上,且以某一主导生物门类的新分子在谱系中的首次出现来定义。根据地层的分布和发育特征,拟将中国早石炭世地层分为岩关阶和大塘阶2个阶,其中岩关阶可分为3个亚阶：塘林冲村亚阶、大圩镇亚阶和小圩镇亚阶。岩关阶的底界以牙形刺Siphonodella sulcata的首次出现来确定,与现行的国际泥盆—石炭系界线相一致;岩关阶的顶界以牙形刺Gnathodus homopunctatus的首次出现来确定,略高于现行的由有孔虫定义的国际杜内—维宪阶界线位置。认为现行的国际杜内—维宪阶界线没能规避岩关阶晚期事件（海平面下降事件）的影响,大量以Eoparastaffella为代表的底栖有孔虫的出现正是此次事件的产物。     

利用风暴沉积类型恢复海平面变化:以北京西山下苇甸剖面寒武纪中晚期风暴沉积为例

华北地区寒武系中发育有大量的风暴沉积,对于此类沉积物的成因前人意见趋于统一,但对其沉积环境的认识仍存在较多争议。在野外细致观察、实测的基础上,结合室内沉积学描述和分析,在北京西山下苇甸剖面寒武系第三统和芙蓉统内识别出5种沉积相类型,并根据沉积环境将其归入3种相组合,分别形成于浅海碳酸盐缓坡潮下带、深潮下带和页岩盆地环境。在研究地层内,共识别出了49层风暴沉积,基于沉积结构和构造特征,这些风暴沉积层可归入4个风暴沉积大类(原地未破碎风暴沉积、原地破碎风暴沉积、近源风暴沉积、远源风暴沉积)和12个亚类,这些风暴沉积类型形成于不同的环境。根据风暴沉积亚类在地层中的分布规律及其所指示的环境类型,恢复了北京西山寒武纪中晚期相对海平面的变化历史。通过与用不同方法恢复的北京西山和鲁西地区同时期海平面变化曲线进行对比,发现利用风暴沉积类型所恢复的海平面变化曲线与使用正常沉积类型恢复的海平面变化曲线具有相同的变化趋势。因此,风暴沉积类型可以用于恢复长时间尺度的海平面变化趋势。     

The stratigraphy of the Drummuck Group (Ashgill), Girvan

The Drummuck Group of the Girvan district (S. W. Scotland) comprises a varied sequence of marine siliciclastic sedimentary rocks some 350 m thick and ranging in age from early Cautleyan to late Rawtheyan (Ashgill Series). Deposition in an unstable slope environment is envisaged. These upper Ordovician rocks crop out in the centre of the Craighead inlier, north of the Girvan valley and are sporadically exposed and locally very fossiliferous. A detailed revision of the Drummuck rocks has permitted, for the first time, the formal lithostratigraphical division of the group. Four main units, in ascending order, the Auldthorns, Quarrel Hill, Lady Burn and South Threave formations are recognized and, within these, a number of smaller, useful divisions are defined. Detailed geological maps of the Drummuck outcrop are presented. Brachiopods numerically dominate the shelly faunas and all the divisions named are characterized by distinctive brachiopod assemblages. Preliminary correlations are discussed with selected upper Ordovician successions elsewhere but the emphasis of this study is placed upon the establishment of a stratigraphical framework within which future detailed research on the Drummuck faunas may be carried out.     

桂西北早、中二叠世常么期和栖霞期含地层及分带

桂西北早中二叠世常么期和栖霞期地层为一套浅海碳酸盐岩相连续沉积,其中类化石十分丰富,自下而上可划分为５个化石带、４个亚带：１）Ｐａｍｉｒｉｎａ－Ｓｃｈｗａｇｅｒｉｎａ带（Ｐａｍｉｒｉｎａｐｕｌｃｈｒａ亚带;Ｓｃｈｗａｇｅｒｉｎａｃｕｓｈｍａｎｉ亚带）;２）Ｓｃｈｗａｇｅｒｉｎａｇｕｅｍｂｅｌｉ带;３）Ｃｈａｌａｒｏｓｃｈｗａｇｅｒｉ－ｎａ－Ｒｏｂｕｓｔｏｓｃｈｗａｇｅｒｉｎａ带（Ｃｈａｌａｒｏｓｃｈｗａｇｅｒｉｎａｖｕｌｇａｒｉｓ亚带;Ｒｏｂｕｓｔｏｓｃｈｗａｇｅｒｉｎａｌｏｎｇｌｉｎｅｎｓｉｓ亚带）;４）Ｂｒｅｖａｘｉｎａｄｙｈｒｅｎｆｕｒｔｈｉ带;５）Ｍｉｓｅｌｉｎａｃｌａｕｄｉａｅ带。同时对命名地点常么组的定义、时代及岩相特征、生物群面貌进行了讨论。     

Conodont Biostratigraphy and Age Determination of the Lower-Middle Triassic Boundary in South Guizhou Province,China

The demarcation of the Lower-Middle Triassic boundary is a disputed problem in global stratigraphic research.Lower-Middle Triassic strata of different types,from platform to basin facies, are well developed in Southwest China.This is favorable for the study of the Olenekian-Anisian boundary and establishing a stratotype for the Qingyan Stage.Based on research at the Ganheqiao section in Wangmo county and the Qingyan section in Guiyang city,Guizhou province,six conodont zones have been recognized,which ca...     

Sequence stratigraphic characteristics and geological significance of the Permian Qixia Stage in northwestern Sichuan Basin

Based on outcrops, drilling, cores, and logging data, the Liangshan Formation and Qixia Formation in the northwestern Sichuan region are analyzed using the theory and method of sequence stratigraphy. Three third-order sequence boundaries are identified, including the basal boundary of Liangshan Formation (type Ⅰ), the boundary between Qi 1 Member and Qi 2 Member (type Ⅱ), and the boundary between the Qixia Formation and the Maokou Formation (type Ⅰ). The Middle Permian Qixia Stage can be subdivided into two third-order sequences (from base to top: SQ1 and SQ2). The SQ1 sequence corresponds to the Liangshan Formation and the Qi 1 Member, and the SQ2 sequence corresponds to the Qi 2 Member. Based on the sequence stratigraphic framework reconstruction of the Qixia Stage, the sedimentary filling pattern of the “onlapping at the base and truncation at the top” is discovered. The contour maps of SQ1 and SQ2 sequence stratigraphic thickness are calculated and plotted. Combined with the stratigraphic filling pattern, the tectonic-palaeogeographical framework of the early SQ1 and SQ2 phases of the Qixia Stage, their geological significance is discussed. At the Qixia Stage, the differentiation between uplift and depression occurs in the northwest and northeast trends. The Hannan uplift, the northern Sichuan uplift, the northern margin uplift and the Guangyuan-Wangcang sag have controlled the sedimentary pattern in the study area. It is indicated that prototype of the Guangyuan-Wangcang Trough began in the Middle Permian Qixia Stage. In the study area, the karst cave-type dolostone reservoir and the karst-type limestone reservoir around the Guangyuan-Wangcang sag rim are favorable exploration areas.     

皖南龙潭阶与长兴阶界线的一种确定方法──层序地层学应用尝试

以层序地层学理论为指导，通过对皖南地区晚二叠世地层沉积层序特征的综合分析。可知该区晚二叠世存在两次海水进退过程，发育两个层序，两层序之界面即为龙潭阶和长兴阶的分界，该界线在视电阻率测井曲线上有较明显的反映，据此可方便地进行地层划分。     

早白垩世陆相九佛堂阶的重新厘定及其层型剖面

通过实测冀北滦平梁根村-东沟村九佛堂组剖面,并在开展多学科系统研究的基础上,把剖面划分为3个岩性段,建立了系统的叶肢介生物地层6个组合,进行辽西九佛堂组—沙海组与冀北滦平九佛堂组的等时性对比;分析剖面的沉积相叠置特征,证明了剖面的沉积连续性和沉积旋回性变化,识别出剖面的3个浅湖相三级层序,重新厘定九佛堂阶的定义及其单位、界线层型。建议将“沙海阶”并入九佛堂阶,单位和界线层型定在冀北滦平盆地西北部梁根村-东山村之间;底界以叶肢介Eosestheria fuxinensis和E. jiufotangensis 的首现为标志。     

中国第一个“金钉子”剖面的建立

中国浙江常山黄泥塘发育了穿越中奥陶统达瑞威尔阶底界的连续地层剖面,笔石和牙形刺的连续演化序列使之得以成为全球对比的标准。经国际地层委员会奥陶系分会、国际地层委员会和国际地科联邮投和批准,已成为达瑞威尔阶的全球层型剖面点。