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1.
庐山筲箕洼组与星子岩群年代地层关系及SHRIMP锆石U-Pb年龄的制约 总被引：5，自引：0，他引：5
本文报道在庐山筲箕洼组中获得细碧岩SHIRMP锆石U-Pb年龄(840±6) Ma,MSWD=1.3,流纹岩锆石U-Pb年龄(833±4) Ma,MSWD=1.4,和流纹岩锆石U-Pb年龄(831±3) Ma,对应的MSWD=1.47.而在星子群流纹岩中获得206pb/238U年龄为(825±5)Ma,对应的MSWD=0.46.笔者依据上述精确锆石年龄,首次提出将筲箕洼组明确定位于星子岩群之下.本文结合“江南造山带”锆石U-Pb年龄:东部变质基底的双桥山群,西部变质基底梵净山群和似盖层下江群以及中部变质基底冷家溪群和似盖层板溪群的锆石SHRIMP U-Pb年龄,将筲箕洼组定位于“武陵运动”之下的新元古代地层.依据星子岩群年龄数据,首次将星子岩群明确定位于筲箕洼组之上与双桥山群为同期的深变质岩.该年龄对限定区域地层对比和构造演化都有着重要意义.上述锆石U-Pb年龄标示了赣西北地区同样存在820 Ma界面上下的新元古代地层,为江南古陆变质地层的对比提供了新的年代学数据. 相似文献
2.
江西庐山新元古代庐山垄群的建立 总被引：8，自引：0，他引：8
本文论述了庐山垄群的建群依据,地层层疗,变形变质特征及地质年代。并创名筲箕洼组和汉阳峰组:前者为海相喷溢的变细碧岩 石英角斑岩组合,并获得变细碧岩、变石英角斑岩锆石U—Pb法年龄分别为917±36Ma、911±134Ma;后者为陆相喷发的火山岩系,获变斑状流纹岩Sm- Nd等时线年龄为845.6Ma、831.5Ma。最后对庐山垄群及筲箕洼组和汉阳峰组与省区域地层对比作了简要阐述。 相似文献
3.
庐山前震旦系由星子群、双桥山群和筲箕洼一汉阳峰组地层构成。通过对庐山前震旦系中锆石U-Pb法定年测定,星子群的斜长角闪岩中锆石的U-Pb法定年结果是1 869±40Ma,由此表明星子群是晚元古代江南造山带的最古老结晶基底;筲箕洼-汉阳峰组中细碧岩和流纹岩的锆石U-Pb法定年结果,分别是917±36Ma和878±51Ma。它们在时代上与邻区登山群、井潭组、松木坞组和上墅组中细碧岩/玄武岩和流纹岩相当,是江南晚元古造山带的重要组成;侵入于星子群和双桥山群的辉绿岩岩墙群中的锆石U-Pb法定年结果是793±156Ma,它是上述造山带的最后岩浆活动的产物。此外,还讨论了"庐山飞来峰"问题。 相似文献
4.
浙江浦江县蒙山地区陈塘坞组在地层柱中的位置
——来自SHRIMP锆石U-Pb年龄的制约 总被引：1，自引：0，他引：1
浙江浦江县蒙山剖面陈塘坞组凝灰岩样品高精度SHRIMP锆石U-Pb年龄分别为825.3Ma±8.1Ma和830Ma±6Ma,结合江绍断裂带以北的赣西地区修水组凝灰岩获得的SHRIMP锆石U-Pb年龄824Ma±5Ma和星子岩群流纹岩中锆石U-Pb年龄825Ma±5Ma,以及庐山筲箕洼组细碧岩的SHRIMP锆石U-Pb年龄840Ma±6 Ma、流纹岩年龄833Ma±4Ma和831Ma±3Ma,将蒙山剖面陈塘坞组和蒙山组明确定位于820Ma之下,双溪坞群之上的地层单元,从传统的平水群体系中独立出来;并将蒙山剖面陈塘坞组之下的蒙山组枕状玄武岩、细碧岩与庐山地区筲箕洼组枕状玄武岩、细碧岩地层序列对比。陈塘坞组年龄的确定对江绍断裂带区域新元古代地层对比和构造演化具有重要意义。 相似文献
5.
庐山前震旦系由星子群、双桥山群和筲箕洼一汉阳峰组地层构成。通过对庐山前震旦系中锆石U-Pb法定年测定,星子群的斜长角闪岩中锆石的U-Pb法定年结果是1 869±40Ma,由此表明星子群是晚元古代江南造山带的最古老结晶基底;筲箕洼-汉阳峰组中细碧岩和流纹岩的锆石U-Pb法定年结果,分别是917±36Ma和878±51Ma。它们在时代上与邻区登山群、井潭组、松木坞组和上墅组中细碧岩/玄武岩和流纹岩相当,是江南晚元古造山带的重要组成;侵入于星子群和双桥山群的辉绿岩岩墙群中的锆石U-Pb法定年结果是793±156Ma,它是上述造山带的最后岩浆活动的产物。此外,还讨论了"庐山飞来峰"问题。 相似文献
6.
燕辽地区长城系串岭沟组及团山子组沉积时代的新制约 总被引：18，自引：15，他引：3
华北克拉通北部燕辽地区是长城系地层出露最全的标准建组地区之一.近年来研究结果表明长城系地层底界年龄比以往所认为的18亿年明显年轻.新的锆石LA-ICP-MS U-Pb测年结果显示,平谷熊耳寨团山子组上部钾质火山岩的锆石207 Pb/206 Pb加权平均年龄为1637±15Ma(95％置信度,N=15,MSWD=0.75),一致年龄为1641±4Ma(1σ,N=14,MSWD=0.12),限定了团山子组上部的沉积时代.蓟县青山岭侵位于串岭沟组地层内闪长玢岩脉的锆石207 Pb/206Pb加权平均年龄为1634±9Ma(95％置信度,N=17,MSWD=0.40),表明串岭沟组地层沉积发生在1634±9Ma之前.结合前人大红峪组火山岩的研究结果还表明,燕辽拗拉槽(裂谷)钾质火山岩的喷发开始于1637±15Ma,在大红峪期(～1625Ma)达到高潮. 相似文献
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8.
新疆阿尔泰南缘大东沟铅锌矿区火山岩LA-ICP-MS锆石U-Pb定年及地质意义 总被引：3，自引：1，他引：2
大东沟铅锌矿位于新疆阿尔泰南缘的克兰盆地,赋存于康布铁堡组上亚组火山-沉积岩系,矿体直接围岩为变质钙质砂岩及不纯的大理岩,矿体呈层状、似层状、透镜状分布,与地层产状一致。利用LA-ICP-MS锆石U-Pb测年法,获得矿区2件康布铁堡组上亚组变质流纹岩加权平均年龄分别为(388.9±3.2)Ma(MSWD=3.3)和(400.7±1.6)Ma(MSWD=1.3)。结合前人的年龄数据,将克兰盆地康布铁堡组的时代厘定为晚志留世末期至早泥盆世(413~389 Ma)。大东沟铅锌矿为火山岩容矿的喷流沉积型矿床(VMS),2件变质流纹岩年龄限定大东沟铅锌矿的成矿作用发生在早泥盆世(401~389 Ma)。 相似文献
9.
赣西北新元古代修水组和马涧桥组SHRIMP锆石U-Pb年龄 总被引：11，自引：1，他引：10
依据精确地测得的修水组凝灰岩SHRIMP锆石U-Pb年龄(824Ma±5Ma,MSWD=1.3),将修水组明确定位于双桥山群的最上部。结合"江南造山带"锆石U-Pb年龄:东部变质基底双桥山群,西部变质基底梵净山群、似盖层下江群和中部变质基底冷家溪群、似盖层板溪群的锆石SHRIMP U-Pb年龄,将双桥山群上部修水组明确地定位于"武陵运动"之下的新元古代地层。同时,首次在上覆地层马涧桥组火山凝灰碎屑岩中获得3组锆石U-Pb年龄,其中一组继承锆石(824Ma±5Ma,MSWD=1.9),反映了修水组被隆起和剥蚀的证据;而最年轻的一组锆石反映了沉积同时代的凝灰岩年龄为(769Ma±8Ma,MSWD=0.55)。依据该年龄数据,将马涧桥组明确定位于板溪期沉积地层。该年龄对限定区域地层对比和构造演化都有重要意义。上述锆石U-Pb年龄标示了赣西北地区同样存在820Ma界面上下的新元古代地层,为江南古陆变质地层的对比提供了新的年代学数据。 相似文献
10.
《沉积与特提斯地质》2015,(4)
采用LA-ICP-MS方法,首次对四川西部新元古界苏雄组层型剖面底部豆状熔结凝灰岩进行了锆石U-Th-Pb同位素测定,获得了两组谐和度极高的年龄数据:805.9±4.4 Ma(N=11,MSWD=0.58)和849.4±6.2 Ma(N=6,MSWD=0.34)。其中,805.9±4.4 Ma代表凝灰岩沉积年龄,与前人报道的苏雄组流纹岩SHRIMP锆石U-Pb年龄(803±12 Ma)高度一致,进一步约束了苏雄组底部火山喷发的起始年代。构造岩浆热事件分析表明,805.9±4.4Ma代表了华南扬子古大陆800 Ma左右的火山喷发事件;而849.4±6.2 Ma则与Rodinia超大陆初始裂解(~850Ma)的同裂谷岩浆活动相对应。 相似文献
11.
Emily Keeble David I. Whiteside Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(2):99-119
Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco. 相似文献
12.
The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts 总被引：4，自引：0，他引：4
The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H2O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H2O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species. 相似文献
13.
Muriel Rocher Stéphane Baize Stéphane Jaillet Edward Marc Cushing Yannick Lozac&#x;h Francis Lemeille 《Comptes Rendus Geoscience》2003,335(8):701-708
Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ1 roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003). 相似文献
14.
正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level 相似文献
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正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7), 相似文献
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正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci- 相似文献
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正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli- 相似文献
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正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.) 相似文献
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正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861 相似文献