收藏本站
《中国科学院地质与地球物理研究所2008学术论文汇编》2009年
收藏 | 手机打开
二维码
手机客户端打开本文

Contribution of subducted Pacific slab to Late Cretaceous mafic magmatism in Qingdao region,China:A petrological record

【摘要】:正The occurrence of the Pishikou mafic dike in the Qingdao region,China provides important constraints on the origin of Late Cretaceous(86-78 Ma) mafic magmatism on the eastern North China craton.The Pishikou mafic dike is distributed in the Cretaceous Laoshan granitoid body,Qingdao region and contains peridotitic and granulitic xenoliths, xenocrysts,and megacrysts.Rocks from the Pishikou mafic dike are basanites and have low SiO_2(42 wt%) and Al_2O_3(12.5 wt%) contents,and high MgO(8 wt%),total alkalis (Na_2O + K_2O4.8 wt%,Na_2O/K_2O1),TiO_2(2.5 wt%),CaO(9 wt,%) and P_2O_5 (1 wt%).In trace element abundances,they are highly enriched in large ion lithophile elements(LILEs) and light rare-earth elements(LREEs)(ΣREE = 339-403 ppm,(La/ Yb)_N = 39-42) without high field strength element(HFSE) depletion.These rocks have radiogenic Sr and Pb,and less radiogenic Nd isotopic compositions[(~(87)Sr/~(86)Sr);0.7059,εNd≈2.7-3.8(~(206)Pb/~(204)Pb)_i≈18.0±0.1].The diagnostic elemental ratios,such as Nb/La, Nb/U,and Nb/Th,are compatible with those of mid-oceanic ridge basalts(MORBs) and oceanic island basalts(OIBs).Therefore,the Pishikou mafic dike has a geochemical feature completely different from those of the Early Cretaceous mafic dikes from the Qingdao region,but similar to those of back-arc basalts from the Japan Sea.This geochemical feature suggests that the Pishikou mafic dike was derived from an asthenosphere source, but contaminated by materials from the subducted Pacific slab.The discovery of this mafic dike thus provides a petrological evidence for the contribution of subducted Pacific slab to the Late Cretaceous magmatism in the Qingdao region of the eastern North China craton.

手机知网App
【相似文献】
中国重要会议论文全文数据库 前10条
1 ;Contribution of subducted Pacific slab to Late Cretaceous mafic magmatism in Qingdao region,China:A petrological record[A];中国科学院地质与地球物理研究所2008学术论文汇编[C];2009年
2 ;Temporal and spatial distribution of Mesozoic mafic magmatism in the North China Craton and implications for secular lithospheric evolution[A];中国科学院地质与地球物理研究所2007学术论文汇编(第二卷)[C];2008年
3 ;Reconstruction and interpretation of giant mafic dyke swarms:a case study of 1.78 Ga magmatism in the North China craton[A];中国科学院地质与地球物理研究所第十届(2010年度)学术年会论文集(上)[C];2011年
4 Simon A.Wilde;;Tectonic setting and significance of 2.3-2.1 Ga magmatic events in the Trans-North China Orogen:New constraints from the Yanmenguan mafic-ultramafic intrusion in the Hengshan-Wutai-Fuping area[A];中国科学院地质与地球物理研究所第十届(2010年度)学术年会论文集(上)[C];2011年
5 ;Geochronology and geochemistry of Early Permian mafic-ultramafic complexes in the Beishan area,Xinjiang,NW China:Implications for late Paleozoic tectonic evolution of the southern Altaids[A];中国科学院地质与地球物理研究所第十届(2010年度)学术年会论文集(上)[C];2011年
6 ;The origin of the Cretaceous gabbros in the Fujian coastal region of SE China:implications for deformation-accompanied magmatism[A];中国科学院地质与地球物理研究所2002学术论文摘要汇编[C];2002年
7 ;Ca.2.5 billion year old coeval ultramafic-mafic and syenitic dykes in Eastern Hebei:Implications for cratonization of the North China Craton[A];中国科学院地质与地球物理研究所第十届(2010年度)学术年会论文集(下)[C];2011年
8 M.Santosh;;Mesoproterozoic mafic and carbonatitic dykes from the northern margin of the North China Craton:Implications for the final breakup of Columbia supercontinent[A];中国科学院地质与地球物理研究所第11届(2011年度)学术年会论文集(下)[C];2012年
9 Patrick Asamoah Sakyi;Sanjeewa P.K.Malaviarachchi;;U-Pb ages and Hf-O isotopes of zircons from Late Paleozoic mafic-ultramafic units in the southern Central Asian Orogenic Belt:Tectonic implications and evidence for an Early-Permian mantle plume[A];中国科学院地质与地球物理研究所第11届(2011年度)学术年会论文集(上)[C];2012年
10 ;Zircon dating,Hf-Sr-Nd-Os isotopes and PGE geochemistry of the Tianyu sulfide-bearing mafic-ultramafic intrusion in the Central Asian Orogenic Belt,NW China[A];中国科学院地质与地球物理研究所第11届(2011年度)学术年会论文集(下)[C];2012年
 快捷付款方式  订购知网充值卡  订购热线  帮助中心
  • 400-819-9993
  • 010-62791813
  • 010-62985026