Crystal Structure and Chemical Composition of Ludwigite from Vranovac Ore Deposit (Boranja Mountain,Serbia)     

Pavle TAN?I?  Radovan DIMITRIJEVI?  Maja POZNANOVI?  Aleksandar PA?EVSKI  Slobodanka SUDAR 《《地质学报》英文版》2012,86(6):1524-1538

The crystal structure of ludwigite from Vranovac ore deposit (Boranja Mt., Serbia) was refined using the X-ray powder diffraction (XRPD) Rietveld method in the space group Pbam to a final RB=7.45% and RF=5.26%. It has the unit cell dimensions of: a=9.2515(2) ?; b=12.3109(2) ?; c=3.03712(7) ?; and V=345.91(1) ?3. The calculated distances and angles are mostly in good agreement with the Mg2+-Fe2+ substitutions across the M(1) and M(3) sites, as well as with the Fe3+-Al3+ replacement in the M(4) site. However, the mean observed M(2)-O distance is considerably shorter than prescribed, due to a slight increase of the Fe3+ content in the M(2) site. Such replacement was compensated by slight increase of the Fe2+ content in the M(4) site, resulting in the (Mg1.48Fe2+0.46Fe3+0.05Mn0.02)2.01(Fe3+0.94Fe2+0.04Al0.02)1.00B1.00O5 composition. The formation temperature was estimated to be about 500–600°C. The influences of the various chemical compositions to the crystallographic parameters, M-O distances, M(3) and M(4) sites shift, distortion parameters and estimated valences, were also studied and compared with other reference samples.  相似文献   

A New Species of Megarhyphus,an Interesting Discovery from the Lower Jurassic of England(Diptera,Anisopodidae)   总被引：1，自引：1，他引：0  

Krzemińska EWA  Coram A. ROBERT  Krzemiński WIES?AW 《《地质学报》英文版》2010,84(4):693-695

<正>The oldest representative of the genus Megarhyphus Kovalev(Diptera:Anisopodidae)is described from the Lower Jurassic(Sinemurian)of England.A summary of our knowledge of Jurassic Anisopodidae is given.  相似文献   

Microelectrona cladara gen.et sp.nov.:A New Protodikraneurini from the Eocene Baltic Amber(Hemiptera:Cicadomorpha:Cicadellidae:Typhlocybinae)     

Jacek Szwedo  Cezary G?bicki  Magdalena Kowalewska 《《地质学报》英文版》2010,84(4):696-704

<正>A new genus Microelectrona gen.nov.and species Microelectrona cladara sp.nov.of the extinct tribe Protodikraneurini of the leafhoppers(Cicadeilidae:Typhlocybinae) from the Eocene Baltic amber is described. The piece of amber containing leafhopper inclusion is broken,unveiling some of the morphological structures,and enabling their studies using scanning electron microscopy.  相似文献   

Review of the El Soplao Amber Outcrop,Early Cretaceous of Cantabria,Spain     

María NAJARRO  Enrique PE?ALVER  Ricardo PéREZ-DE LA FUENTE  Jaime ORTEGA-BLANCO  Cesar MENOR-SALVáN  Eduardo BARRóN  Carmen SORIANO  Idoia ROSALES  Rafael LóPEZ DEL VALLE  Francisco VELASCO  Fernando TORNOS  Véronique DAVIERO-GOMEZ  Bernard GOMEZ  Xavier DELCLòS 《《地质学报》英文版》2010,84(4):959-976

<正>El Soplao outcrop,an Early Cretaceous amber deposit recently discovered in northern Spain (Cantabria),has been shown to be the largest site of amber with arthropod inclusions that has been found in Spain so far.Relevant data provided herein for biogeochemistry of the amber,palynology,taphonomy and arthropod bioinclusions complement those previously published.This set of data suggests at least two botanical sources for the amber of El Soplao deposit.The first(type A amber)strongly supports a source related to Cheirolepidiaceae,and the second(type B amber)shows non-specific conifer biomarkers.Comparison of molecular composition of type A amber with Frenelopsis leaves(Cheirolepidiaceae)strongly suggests a biochemical affinity and a common botanical origin.A preliminary palynological study indicates a regional high taxonomical diversity,mainly of pteridophyte spores and gymnosperm pollen grains.According to the preliminary palynological data,the region was inhabited by conifer forests adapted to a dry season under a subtropical climate.The abundant charcoalified wood associated with the amber in the same beds is evidence of paleofires that most likely promoted both the resin production and an intensive erosion of the litter,and subsequent great accumulation of amber plus plant cuticles.In addition,for the first time in the fossil record, charcoalified plant fibers as bioinclusions in amber are reported.Other relevant taphonomic data are the exceptional presence of serpulids and bryozoans on the surfaces of some amber pieces indicating both a long exposure on marine or brackish-water and a mixed assemblage of amber.Lastly,new findings of insect bioinclusions,some of them uncommon in the fossil record or showing remarkable adaptations,are reported.In conclusion,a documented scenario for the origin of the El Soplao amber outcrop is provided.  相似文献   

First Psocodean (Psocodea,Empheriidae) from the Cretaceous Amber of New Jersey     

Dany Azar  André NEL  Julian F. PETRULEVI?IUS 《《地质学报》英文版》2010,84(4):762-767

<正>Representatives of the extinct psocid family Empheriidae are known from Eocene Baltic amber, Lowermost Eocene French amber(Oise),and Lower Cretaceous Spanish amber(Alava).We report herein the first discovery of an empheriid psocid from the Cretaceous amber of New Jersey as Jerseyempheria grimaldii gen.et sp. nov.The fossil is figured and described.The new species is distinguished from related taxa.A discussion and checklist of Empheriidae are provided.  相似文献   

A New Thorny Lacewing (Insecta: Neuroptera: Rhachiberothidae) from the Early Cretaceous Amber of Lebanon     

Julian F. PETRULEVI?IUS  Dany Azar  André NEL 《《地质学报》英文版》2010,84(4):828-833

<正>A new genus and species of Rhachiberothidae,Raptorapax terribilissima gen.et sp.nov.from the Cretaceous amber of Lebanon is described.The new genus is assigned to the subfamily Paraberothinae.The new material confirms the great diversity of the group in the Cretaceous age and its decrease in diversity in recent times.  相似文献   

A New Family of Moths from the Middle Jurassic (Insecta: Lepidoptera)   总被引：1，自引：1，他引：0  

HUANG Diying  André NEL  Jo?l MINET 《《地质学报》英文版》2010,84(4):874-885

<正>Three lepidopteran species,from the Middle Jurassic Daohugou beds(inner Mongolia,China),are described in a new family,Mesokristenseniidae,and new genus,Mesokristensenia,which could represent the sister group of the Micropterigidae.Mesokristensenia differs from all extant Lepidoptera,but one genus(Agathiphaga, Agathiphagidae),in retaining four median veins in the forewing,a plesiomorphy also present in many Trichoptera. Evidence for placing Mesokristensenia in the Lepidoptera includes four traits,notably a previously unrecorded autapomorphy of this insect order:beyond stem M1+2,vein M1 is bent and connected to cross-vein r-m(in both wing pairs).Among 24 characters taken into account to assess the systematic position of Mesokristensenia,12 are considered informative for a cladistic analysis involving this fossil taxon and the four suborders recognized in present-day Lepidoptera(Zeugloptera,Aglossata,Heterobathmiina,and Glossata).  相似文献   

古新世以来郯庐断裂的位移量及其对莱州湾凹陷的控制   总被引：4，自引：2，他引：2  

彭文绪  张如才  孙和风  史浩  吴奎  贺电波  姚以泰 《大地构造与成矿学》2010,34(4)

高分辨三维地震可视化及方差切片分析显示,郯庐断裂渤海海域莱州湾段北北东向断裂系发育。断层在水平方差切片上的拖拽现象、断裂带内部断层的组合关系以及凹陷沉积中心的迁移等,表明古新世以来该区存在右旋走滑运动。假设在东、西两支断层的走滑拉分作用下,根据可容纳空间不变原理,设计了三角形模型、长方形模型、半地堑型模型以及地堑型模型共四种模型,计算莱州湾凹陷南北长度和凹陷深度的关系,其中半地堑模型计算得到的郯庐断裂的水平位移为7km。结合断层的平面分布和断层的切割关系,表明古新世以来郯庐断裂的走滑拉分作用难以控制莱州湾凹陷的形成,走滑拉分作用只是在走滑断裂带内部形成了局部小型洼地,其规模很小,影响非常有限。  相似文献   

关于西阿翼龙系统位置的简单注释及与其它翼龙类关系的评论     

Bruno C. VILA NOVA  Alexander W. A. KELLNER  Juliana M. SAY?O 《地球学报》2010,31(Z1):73-75

Cearadactylus atrox is one of the first pterosaurs unearthed from the Araripe Basin (Northeast Brazil) (Leonardi and Borgomanero 1983, 1985) (Fig.1). The fossil was preserved in a calcareous concretion typical of the Romualdo Formation and comprised an almost complete skull with lower jaw, but lacked the occipital region.  相似文献   

RELATION BETWEEN THE MRT BUILDING AND UNDERGROUND SPACE EXPLOITATION——A Case in Guangzhou City     

LI Wen-ling  YAN Xiao-pei  WANG Fang 《中国地理科学(英文版)》2003,13(4)

Thehumandevelopmentalhistoryrevealsthatmanhasneverneglected exploitingtheundergroundspace, fromtheprimitive'caveliving' tothe'undergroundvillage' inMatermataofTunis,fromthesubsided'cavedwelling' inthenorthwestofChinatothepre-sent'undergroundcity'.Theundergroundspacehasbeenexploitedwidelyanddeeply. Thewidespreadutilization oftheurbanunder-groundspacetookplaceafter thebeginningofindus-trialrevolutionsandurbanization.Dueto seriesofproblemsonurbandevelopmentresultedfromtheoverconcentrationofpo…  相似文献