浙江晚泥盆世的石松类(Lycopodiales)化石

本文描述了萧山虎山和长兴泗安晚泥盆世地层中的石松类化石,共有6个属9个种,其中包括1个新属和3个新种,分别:SpinolepidodendronhangzhouenseGen.etsp.nov,SublepidodendronXianshanensesp.nov,Eolepi-dodendronhushanensesp.nov.。认为浙江晚泥盆世植物化应归于以Leptopnloeumrhombicum-Sublepidodendronxi-aoshanense—Xihuphyllummegalofolium为代表的组合。     

The First Discovery of the Earliest Devonian Conodont Zonal Fossil from the "Gavuu Member" in Mushgai Area of South Gobi,Mongolia

1IntroductionThe study of the Palaeozoic stratigraphy has been carried out in Mongolia for more than 80 years, but merely limited to the benthic macrofossiles. For the last ten years the study of conodonts has been em-ployed in biostratigraphic analyses. But up to now, Palaeozoic conodont sequences in Mongolia have not been recognized. Conodonts as a leading fos-sil group, should be paid much attention for dating ages of the Palaeozoic rocks and for their interna-tional correlations. …     

The First Discovery of the Earliest Devonian Conodont Zonal Fossil from the "Gavuu Member" in Mushgai Area of South Gobi,Mongolia

Conodont Caudicriodus woschimidti woschmidti has been found from a big outcrop (hill) of the Bayan-Kho-shuu Ruins Section which was previously assigned to the Silurian Gavuu Member of the Mandalovoo Formation. This isfirst time to find the lowermost Devonian conodont zonal fossil in Mongolia. The lower part of the Gavuu Member is Silurian. But the strata from where we collected samples M-9～M-12 definitely belong to Lower Devonian (lower Lochko-vian) rather than Lower Silurian. The Mandalovoo Formation should be named Mandalovoo Group, and its three members should be changed into three formations.     

浙江雁荡山地区晚中生代火山-沉积岩系地层归属讨论

浙江雁荡山地区晚中生代火山-沉积岩系的地层归属,存在磨石山群和永康群两种截然不同的认识.本文在详细分析对比了该区与浙东南磨石山群和永康群的地层层序、岩相组合、接触关系,古生物组合,同位素地质年龄,Nd同位素体系特征以及火山构造类型等方面的资料,认为除原划为永康群盆地外,仅桥下地区有面积不大的永康群,其余均为早白垩世早期的磨石山群,而不是早白恶世晚期至晚白垩世早期的永康群.特别是在永嘉枫林村北,首次发现并证实了不整合覆于震旦系浅变质岩之上的大爽组地层,为浙东南沿海晚中生界火山-沉积岩系的划分对比提供了坚实的基础.     

伊犁地块北缘别珍套山中泥盆统汗吉尕组物源特征及其地质意义

天山造山带位于中亚造山带西南缘,是探索中亚造山带增生造山过程的重要窗口.西北天山是伊犁地块与准噶尔地块的结合部位,保存了两者之间构造演化的重要地质信息.出露于伊犁地块北缘别珍套山的泥盆系是记录西北天山晚古生代早期构造演化过程的重要载体.基于此,对中泥盆统汗吉尕组砂岩进行岩相学和LA-ICP-MS碎屑锆石U-Pb定年与微...     

浙江中生代浅成热液金银成矿系统的自组织与耗散结构

浙江中生代浅成热液金银矿床多具明显的热液蚀变 (矿化 )分带—自组织结构。通过对围岩蚀变—矿化过程中的W /R(水 /岩 )比值、元素的带出 (λ)量[EO(I)A] ,熵变 (ΔS)、成矿成岩时差(Δti)和S°298/di(标准熵 /离子密度 )比值、盐度 (St)、P(压力 )、fs2(硫逸度 )和fo2(氧逸度 )、δ18OH2O 和δD、206Pb/204Pb和207Pb/204Pb值等变化的研究 ,表明浅成热液金银成矿系统是一个非平衡 (距热力学平衡态有一定距离 )的开放系统 ,矿床都是在开放环境下成矿流体通过能量的不断耗散并与围岩发生物质交换的一种自组织过程中形成的 ,具耗散结构的特征。一般W/R、EO(I)A和Δti与S°298/di∝MSOD(成矿系统开放程度 )。也就是说 ,围岩蚀变 -矿化过程中W /R比值、元素的带出(入 )量和Δti与S°298/di比值及ΔS值较大 ,一般成矿系统的开放程度也较高 ,成矿一般也较有利     

Organic geochemistry and source rock potential assessment of Late Paleocene Patala Formation in Margalla Hill Range,North Pakistan

Black shales of the Paleocene Patala Formation are proven source rocks for conventional hydrocarbons in southern Potwar Basin of Pakistan and are assumed to be effective source rocks towards north in the Margalla Hill Range of Pakistan. In this regard, the current study focuses on source rock geochemistry of the Paleocene Patala Formation to assess its source rock potential, organic matter types and thermal maturity levels in the Mar-galla Hill Range of North Pakistan. Source rock generative potential, kerogen types and thermal maturation of the analysed rock samples were unraveled by using Rock-Eval pyrolysis Tmax, TOC (total organic carbon) and vitrinite reflectance ( R0 ) analyses. TOC analysis coupled with S2 yield revealed poor to fair source rock quality encountered within the formation. The pyrolysis Tmax vs Hydrogen Index ( HI) , showed mostly Type Ⅲ kerogen dominated by thermally immature to mature organic matter. The HI and genetic potential is low and revealed poor hydrocarbon generation potential of the formation. The S1 vs TOC plots confirm the indigenous nature of the hydrocarbons hosted by Patala Formation. The vitrinite reflectance outcomes indicated immature to mature source rock beds lying in dry gas zone. The HI and OI signatures and abundance of Type Ⅲ kerogen are indica-ting dominance of terrestrial organic matter within the formation. Overall, the investigated Patala Formation ex-posed at the studied section of Margalla Hill Range, Pakistan acts as a poor source rock unit for liquid hydrocar-bon generation but holds prospects for dry gas generation in the study area.     

Ginkgo from Lower Cretaceous Changcai Formation in Helong of Jilin, NE China

Based on gross morphological and cuticular study, two species of Ginkgo From the Lower Cretaceous Changcai Formation in Helong of Jilin. were identified from this area for the first time, including Ginkgo coriacea Florin and G.sibiricaHeer. The study is significant for better understanding the paleophytogeographic, paleoecologicandstratigraphic characters of the Early Cretaceous Changcai flora.