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1.
对浙江建德寿昌地区中生代陆相火山-沉积地层建德群进行了系统的同位素年代学研究。确定该岩群下限年龄为130Ma;上限年龄为117Ma。其时代相当于早白垩世,而不是晚侏罗世。所属各地层组年龄自下而上分别为:劳村组130Ma;黄尖组128Ma;寿昌组122Ma;横山组117Ma。较北方热河群相对年轻些。本岩群火山活动可分为130-128Ma和122-117Ma两个喷发旋回。本区建立的建德群同位素年代学系统剖面,可作为研究中国东南乃至东部地区中生代陆相火山-沉积地层时代的时标。 相似文献
2.
冀北张家口组、义县组火山岩SHRIMP定年兼论中国东部大兴安岭兴安岭群和东南沿海火山岩地层时代 总被引：1，自引：0，他引：1
冀北张家口组和义县组火山岩锆石 U-Pb定年结果表明 ,张家口组的时代为 1 3 5～ 1 3 0 Ma,义县组的时代为 1 2 9～ 1 2 0 Ma,均属早白垩世。揭示出冀北—辽西地区早白垩世火山沉积盆地的形成和火山活动的时代均具由西向东变新的特征 ,即滦平盆地火山活动始于 1 3 5Ma,承德盆地骆驼山一带始于 1 3 0 Ma,辽西始于 1 2 8Ma。根据年代地层和生物地层资料的对比表明 ,组成中国东部大兴安岭火山岩带的兴安岭群时代主体为早白垩世早—中期 ,组成东南沿海火山岩带的建德群和石帽山群及其相当地层的时代为早白垩世中—晚期 ,因此热河生物群和建德… 相似文献
3.
华南晚中生代陆相岩石地层单元的精确时代和对比一直存在争议。通过总结新近发表火山岩锆石U-Pb同位素年龄,在本次工作补充基础上,修订并厘定了华南赣杭带晚中生代陆相火山-沉积盆地中岩石地层单元的时代和关系,取得了5个方面的基本认识。(1)浙西磨石山群、建德群和永康群时代分别为早白垩世早-中期(~145~120 Ma、~140~115 Ma)和晚期(~125~105 Ma),显示形成有先后,有共存时段;建德群的劳村组、黄尖组、寿昌组之间,永康群的馆头组与朝川组之间存在同时异相的侧向叠加关系;中戴组下部年龄98 Ma指示衢江群始于晚白垩世初期;建德盆地经典寿昌剖面和丽水盆地经典老竹剖面均由两个相似的地层层序重复组成。(2)闽西永安盆地发育赣杭带晚中生代最老地层,兜岭群形成于晚侏罗世-早白垩世早期(~162~125 Ma),石帽山群主体构建于早白垩世中晚期(~135~95 Ma),赤石群的沙县组时限为Aptian晚期-Cenomanian早期(~115~93 Ma),白牙山组存在时限甚短(~100~97 Ma),崇安组可能晚于~100 Ma;坂头组与下渡组之间,寨下组与黄坑组之间,沙县组、均口组、崇安组及白牙山组之间并非单一上下关系,大多存在侧向叠加的同时异相现象。(3)赣东武夷群建造于早白垩世早期(~145~125 Ma),火把山群沉积晚于Aptian早期(~122 Ma),赣州群初始沉积时间可能晚于Albian早期(~110 Ma),圭峰群可能始于晚白垩世初期(~100 Ma之后);打鼓顶组、鹅湖岭组、石溪组之间,河口组与塘边组之间主体为同时异相建造,侧向叠加可能性甚大;罗塘组、冷水坞组和周家店组,河口组与莲荷组分别可能为同物异名。(4)赣杭带晚中生代地层演化可分为3个阶段:Ⅰ-早白垩世早期火山地层阶段,Ⅱ-早白垩世晚期火山-沉积地层阶段,Ⅲ-晚白垩世沉积地层阶段,相应时期的地层记录或许可以各自用一个超群统名,这3个地层演化阶段一定程度上反映了3个构造演化阶段。(5)赣杭带火山-沉积盆地"组"岩石地层单元广泛的侧向叠加同时异相关系表明,有必要对华南晚中生代陆相地层上下和侧向关系进行重新审视。 相似文献
4.
海拉尔盆地中生代火山岩锆石U-Pb年代学及其地质意义 总被引：1，自引：0，他引：1
本文报导了海拉尔盆地巴彦呼舒凹陷楚2井南屯组(K1n)和楚3井兴安岭群(J3xn)6个流纹岩中锆石的LA-ICPMS U-Pb定年结果,以便精确限定盆地内火山岩形成的时代以及火山活动与盆地形成和演化之间的关系.6个流纹岩中的锆石均呈自形-半自形晶,显示典型的岩浆生长环带或条痕状吸收,并具有较高的Th/U比值(0.48 ～2.41),表示其为岩浆成因.楚2井南屯组(K1n)1个流纹岩中锆石的206Pb/238U年龄介于123～ 134Ma之间,其加权平均年龄为127±2Ma,代表了该火山岩的形成时代为早白垩世晚期;楚3井兴安岭群5个样品的锆石206Pb/238U年龄分别为120±1Ma、127±4Ma、125±1Ma、125±1Ma和126±1Ma,表明其形成时代为早白垩世晚期,并非前人确定的晚侏罗世.除了上述年龄外,流纹岩中还存在140～168Ma的捕获锆石,这与区域上出露的塔木兰沟组火山岩的形成时代相吻合.根据上述定年结果并结合前人的资料,海拉尔盆地南屯组和兴安岭群火山岩的形成时代为早白垩世晚期,火山活动时间为中生代晚侏罗世-早白垩世,这与我国东部中生代火成岩活动的年代一致.从东北地区中生代火山岩的定年结果及其空间展布来看,海拉尔盆地的形成与演化应与环太平洋构造体系有关,即古太平洋板块的俯冲作用. 相似文献
5.
6.
论浙江中生代晚期地层划分 总被引：17，自引：4，他引：17
中生代晚期，浙江先后形成了寿昌型、永康型和金衢型三种不同构造类型的盆地，三者呈叠加关系，其堆积物属于３个地质时期。在理顺其层序的基础上，通过对３个不同时期古生物群和同位素年龄资料的综合分析，认为衢江群（天台群）属于早白垩世晚期一晚白垩世；永康群属于早白垩世中晚期；建德群（磨石山群）属于晚侏罗世－早白垩世早期。如果采用１３０Ｍａ作为侏罗－白垩系划界时标，其界线应划在横山组与寿昌组及相应的岩组之间。 相似文献
7.
赣南—粤北版石群及其地质时代 总被引：11，自引：1，他引：10
赣南—粤北中生代晚期存在上、中、下3个不同时代的火山岩系,其中上火山岩系称为版石群。根据岩性岩相特征,版石群可进一步划分为两个岩组:下岩组称为合水组,以砾岩、砂岩、页岩等沉积岩为主、夹火山岩,代表火山活动初始期的产物;上岩组称为优胜组,岩性为流纹岩、流纹质凝灰岩、熔结凝灰岩,代表火山活动喷发期的产物。长塘盆地优胜组熔结凝灰岩全岩RbSr等时线年龄为89.5Ma;仁差盆地优胜组流纹岩全岩RbSr等时线年龄为91.9～94Ma,熔结凝灰岩锆石UPb法年龄为86.5Ma,次流纹斑岩锆石UPb法年龄为93.5Ma;菖蒲盆地优胜组流纹岩全岩RbSr等时线年龄为104Ma;版石盆地优胜组流纹岩全岩RbSr等时线年龄为72.2Ma,全岩KAr法年龄为77.6Ma,可见版石群优胜组的地质时代为早白垩世晚期—晚白垩世早期。另外,合水组的生物化石反映出早白垩世的特征,因此,将版石群置于早白垩世—晚白垩世早期是可信的。 相似文献
8.
《地质学报》2010,(12)
本文应用LA-ICPMS锆石U-Pb定年方法,对博格达山北侧原石炭系沙雷赛尔克组及沙玛尔沙依组开展了碎屑锆石U-Pb年代学研究。测年结果显示沙雷赛尔克组碎屑锆石表面年龄值分布较宽(298～2215Ma),主要集中在298～344Ma,主峰值年龄为305Ma,次要峰值为501～538Ma,并见有一粒1331Ma及两粒2146Ma、2215Ma的碎屑锆石;沙玛尔沙依组碎屑锆石表面年龄分布较窄(280～523Ma)且相对集中(299～358Ma),主峰值年龄为345Ma,次要峰值年龄为428～450Ma及507～523Ma。通过样品岩石学特征、碎屑锆石Th、U含量、CL组构特征及区域地质资料分析,初步获得以下认识:①博格达山北侧原定义为石炭纪地层的沉积时代应为早石炭世—早二叠世,其中奇尔古斯套群时代为早石炭世晚期—晚石炭世早期,居里得能组—扬布拉克组时代为晚石炭世中期及晚期,沙玛尔沙依组时代为早二叠世早期,缪林托凯陶山组沉积时代及其与沙玛尔沙依组的关系尚有待于进一步研究;②沙雷赛尔克组及沙玛尔沙依组砂岩主要来自于准噶尔盆地,主要物质供给区为区内略早于或与其同时代沉积的石炭纪地层;③博格达晚古生代大陆裂谷在早石炭世已形成,晚石炭世开始衰退,并发生两次弱造山作用,中二叠世夏子街期最终闭合。 相似文献
9.
浙江中生代晚期火山—沉积岩系层序和时代 总被引：33，自引：7，他引：26
浙江中生代晚期火山—沉积地层由上、下两个岩系组成,上岩系包括横山组、永康群、衢江群及天台群,下岩系包括建德群和磨石山群。这两个岩系的同位素年龄范围分别在１１０～９０Ｍａ和１３５～１２０Ｍａ。根据同位素地质年代结合该区火山—沉积地层的古地磁和古生物研究资料,我们提出上岩系的形成时代为早白垩世晚期至晚白垩世早期,下岩系为早白垩世早期 相似文献
10.
新疆东部博格达山北侧石炭系砂岩碎屑锆石U_Pb定年及其地质意义 总被引：2，自引：0，他引：2
本文应用LA-ICPMS锆石U-Pb定年方法,对博格达山北侧原石炭纪沙雷赛尔克组及沙玛尔沙依组开展了碎屑锆石U-Pb年代学研究。测年结果显示沙雷赛尔克组碎屑锆石表面年龄值分布较宽（298～2215Ma）,主要集中在298～344Ma,主峰值年龄为305Ma,次要峰值为501～538Ma,并见有一粒1331Ma及两粒2146、2215Ma的碎屑锆石;沙玛尔沙依组碎屑锆石表面年龄分布较窄（280～523Ma）且相对集中（299～358Ma）,主峰值年龄为345Ma,次要峰值年龄为428～450Ma及507～523Ma。通过样品岩石学特征、碎屑锆石Th、U含量、CL组构特征及区域地质资料分析,初步获得以下认识：（1）博格达山北侧原定义为石炭纪地层的沉积时代应为早石炭世～早二叠世,其中奇尔古斯套群时代为早石炭世晚期～晚石炭世早期,居里得能组～扬布拉克组时代为晚石炭世中期及晚期,沙玛尔沙依组时代为早二叠世早期,缪林托凯陶山组沉积时代及其与沙玛尔沙依组的关系尚有待于进一步研究;（2）沙雷赛尔克组及沙玛尔沙依组砂岩主要来自于准噶尔盆地,主要物质供给区为区内略早于或与其同时代沉积的石炭纪地层;（3）博格达晚古生代大陆裂谷在早石炭世已形成,晚石炭世开始衰退,并发生两次弱造山作用,中二叠世夏子街期最终闭合。 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.
Gilles Serge Odin 《Comptes Rendus Geoscience》2002,334(6):409-414
Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414. 相似文献
13.
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
14.
Emmanuel Skourtsos Daniel Vachard Alexandra Zambetakis-Lekkas Rossana Martini Louisette Zaninetti 《Comptes Rendus Geoscience》2002,334(12):925-931
Some olistolites reworked in a Tertiary flysch of Mount Parnon (Peloponnesus, Greece) exhibit a Late Permian assemblage, dominated by Paradunbarula (Shindella) shindensis, Hemigordiopsis cf. luquensis and Colaniella aff. minima. This association corresponds to the Late Wuchiapingian (=Late Dzhulfian), a substage whose algae and foraminifera are generally little known. Contemporaneous limestones crop out in the middle part of the Episkopi Formation in Hydra, but they are rather commonly reworked in Mesozoic and Cainozoic sequences. The palaeobiogeographical affinities shared by the foraminiferal markers of Greece, southeastern Pamir, and southern China, are very strong (up to the specific level), and are congruent with the Pangea B reconstructions. To cite this article: E. Skourtsos et al., C. R. Geoscience 334 (2002) 925–931. 相似文献
15.
正20141596 Liu Yunhuan(School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,China);Shao Tiequan Early Cambrian Quadrapyrgites Fossils of Xixiang Boita in Southern Shaanxi Province(Journal of Earth Sciences and Environment,ISSN1672-6561,CN61-1423/P,35(3),2013,p.39-43,3 illus.,20 refs.) 相似文献
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正20141719 Chen Zhijun(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China);Chen Jianguo Automated Batch Mapping Solution for Serial Maps:A Case Study of Exploration Geochemistry Maps(Journal of Geology,ISSN1674-3636,CN32-1796/P,37(3),2013,p.456-464,2 illus.,2 tables,10 refs.) 相似文献
17.
正20140962 Chen Fenning(Xi’an Institute of Geology and Mineral Resources,Xi’an710054,China);Chen Ruiming Late Miocene-Early Pleistocene Ostracoda Fauna of Gyirong Basin,Southern Tibet(Acta Geologica Sinica,ISSN0001-5717,CN11-1951/P,87(6),2013,p.872-886,6illus.,56refs.) 相似文献
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正1.IGNEOUS PETROLOGY20142008Cai Jinhui(Wuhan Center,China Geological Survey,Wuhan 430205,China);Liu Wei Zircon U-Pb Geochronology and Mineralization Significance of Granodiorites from Fuzichong Pb-Zn Deposit,Guangxi,South China(Geology and Mineral Resources of South China,ISSN1007-3701,CN42-1417/P,29(4),2013,p.271-281,7illus., 相似文献
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正20141205Cheng Weiming(State Key Laboratory of Resources and Environmental Information System,Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China);Xia Yao Regional Hazard Assessment of Disaster Environment for Debris Flows:Taking Jundu Mountain,Beijing as an 相似文献
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正20141266Fan Chaoyan(Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes,Guangzhou 510275,China);Wang Zhenghai On Error Analysis and Correction Method of Measured Strata Section with Wire Projection Method(Journal of 相似文献