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| 1 | SHRIMP Age and Geochemistry of the Bikou Volcanic Terrane:Implications for Neoproterozoic Tectonics on the Northern Margin of the Yangtze Craton显示文摘The Bikou volcanic terrane is predominated by subalkaline tholeiitic lavas. Rock samples display lower initialratios of Sr and Nd, 0.701248-0.704413 and 0.511080-0.512341 respectively. 207pb and 208pb are significantly enriched inthe lavas. Most samples have positive εNd, which indicates that the magma was derived from EM-type mantle source,while a few samples with negative εNd indicate that there was contamination in the magma evolution. Magmadifferentiation is demonstrated by variations of LREE and LILE from depletion to enrichment. Additionally, normalizedREE patterns and trace elements showed that lavas from the Bikou volcanic terrane have similar characteristics to those ofbasalts in arc settings caused by subduction and collision. Analyses showed that the Bikou volcanic terrane is a volcanicarc. New evidence proved that the Hengdan Group, north of the Bikou arc, is a turbidite terrane filling a forearc basin.Consequently, the Bikou volcanic terrane and the Hengdan turbidite terrane construct an arc-basin system. New SHRIMPages showed that this arc-basin system developed on the northern margin of the Yangtze craton in the Neoproterozoic(846-776 Ma), and this arc-basin system is in agreement with the tectonic processes of Rodinia in the Neoproterzoic. | YANQuanren WANGZongqi A.D.HANSON P.A.DRUSCHKE YANZhen LIUDunyi JIANPing SONGBiao WANGTao JIANGChunfa | 2003 | Acta Geologica Sinica(English Edition)2003，77，4： | 32 |
| 2 | 南秦岭横丹浊积岩系——晚古生代发育于扬子板块被动陆缘上的弧前盆地充填物显示文摘南秦岭横丹浊积岩系是一套巨厚的浊流沉积,以向南或南东倾的单斜构造产出。由下而上,该沉积层序包括深水盆地、深水浊积扇和斜坡水道3个相序。相应地,沉积物粒度变粗,厚度变大,火山质组分含量增加,凝灰层大量发育,表明横丹浊积岩系为活动型浊积岩;其古水流方向为NNW—NNE向,物源区为南侧的碧口火山岩系。另外,横丹浊积岩系内还见石英岩、重结晶大理岩成分的砾石,说明其物源还包括被动陆缘环境的沉积物。相序、组构、沉积特征和物源区综合分析表明,横丹浊积岩系为弧前盆地充填物。构筑这一弧前盆地的动力学机制是洋壳板块向南俯冲于扬子板块被动陆缘之下,时代可能晚于中晚泥盆世。 | 闫全人 王宗起 A.D.Hanson P.A.Druschke 王涛 闫臻 | 2002 | 地质通报2002，21，8： | 25 |
| 3 | 南秦岭关家沟组砾岩的时代、成因环境及其构造意义显示文摘关家沟组地层位于南秦岭造山带,因缺乏化石证据,其地层时代长期悬而未决,该套地层在南秦岭地区地质演化过程中构造含义始终模糊不清.关家沟组砾岩厚度约为2050m,为一套向上变粗、变浅的进积层序,结构和物质组成上表现为不成熟海相浊积砂岩和砾岩.虽然南北两侧为断层所限,但关家沟组变质变形很弱.北侧为泥盆系三河群,南侧为新元古界横丹群,关家沟组中含有大量花岗岩和火山岩碎屑.对采自其中的花岗岩和火山岩砾石进行了单矿物(斜长石和钾长石)40Ar/39Ar热年代学研究.两个测年结果分别给出了花岗岩和火山岩砾石的冷却年龄为219.69±0.49和216.46±0.59Ma,与早中生代秦岭全面碰撞作用时期(240-220)Ma的构造岩浆活动的时代大体一致,暗示关家沟组可能沉积于晚三叠世Norian晚期,约220M.沉积学分析和热年代学研究表明:关家沟组可能是残余洋盆的沉积充填物.区域上,该残余洋盆为晚古生代一早中生代阿尼玛卿洋与勉略洋或中央造山带南侧的一部分. | 闫全人 A.D.Hanson 王宗起 P.A.Druschke 闫臻 王涛 卢海峰 | 2004 | 科学通报2004，49，14： | 11 |
| 4 | Timing and setting of Guan-jiagou conglomerate in South Qinling and their tectonic im-plications显示文摘Located in the southern Qinling Mountains of central China, the Guanjiagou Formation has been a con-troversial issue with regard to its depositional age and tec-tonic implications. Being comprised of an approximately 2050 m thick succession of texturally and compositionally immature, presumed marine turbiditic sandstones and con-glomerate, the Guanjiagou Formation consists of an overall prograding- and coarsening-upward megasequence. Al-though bounded by faults on both its northern and southern margins, it is weakly metamorphosed and deformed. To the north is the Devonian Sanhekou Group and to the south is the Neoproterozoic Hengdan Group. The lower portion of the sequence contains granitic and volcanic clasts (Guanjiagou conglomerate). The feldspars from these clasts were dated using the 40Ar/39Ar method. Two cooling ages of 219.690.49 and 216.460.59 Ma, for K-feldspar from a granitic clast and plagioclase from a volcanic clast, respectively, were obtained. These ages are identical to the time of regional igneous ac-tivities (ca. 240—220 Ma) and are interpreted as the prod-ucts of magmatism associated with collision in the Qinling orogenic belt in the Early Mesozoic, suggesting that the Guanjiagou Formation was deposited in the Norian of the Late Triassic, ca. 220 Ma. Therefore, 40Ar/39Ar and sedimen-tary analyses suggest that the Guanjiagou Formation con-tains sediments that may have filled in a remnant ocean ba-sin, which might be part of the Anyemaqen-Mianle ocean, or Tethys on the southern side of Central Orogenic Belt in China during the Late Paleozoic to Early Mesozoic. | YANQuanren A.D.Hanson WANGZongqi P.A.Druschkel YANZhen WANGTao LUHaifeng | 2004 | Chinese Science Bulletin2004，49，16： | 5 |
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