甘肃夏河地区印支期埃达克岩的厘定及其意义被引量：15

GEOCHEMICAL CHARACTERISTICS AND GEOLOGICAL SIGNIFICANCE OF ADAKITIC GRANITOIDS IN XIAHE COUNTY OF GANSU PROVINCE

导出

摘要对出露于甘肃夏河地区，隶属西秦岭的印支晚期复式岩体的地质地球化学研究表明。其岩石具有与典型埃达克岩相似的特征：SiO2多数（72％～58％），高Al2O3（16．7％～14．6％），Sr多数大于（400×10^-6），低Y（16×10^-6～7×10^-6）和Yb（1．7×10^-6～0．56×10^-6），明显亏损Nb和Ta，稀土元素分异强烈，富集LREE，低HREE，并有较弱的Eu负异常（δEu为0．9～0．4）在（La／Yb）N-Yb和Sr／Y-Y图解上样品主要落入埃达克质岩区域。该套埃达克质岩的厘定，对研究秦岭造山带晚古生代古特提斯洋的构造演化、地球动力学特征具有重要意义。 The late Indosinian granitoids in Xiahe area of Gansu Province belong to west Qinling orogenic belt. A study of their petrochemical and geochemical characteristics shows that they have the typical characteristics of ＂adakite＂. These rocks have the following characteristics： Most of SiO2 （70%-58%）, high Al2O3（16.7%-14.6%） and Sr （most of them〉400×10^-6）, and low in Sr/Y（16×10^-6～7×10^-6） and Y ratio （1.7×10^-6～0.56×10^-6）; There exist very prominent negative Nb and Ta anomaly in the trace element spidergram. REE distribution pat- terns show strong REE segregation and belong to the type of enriched LREE, but depletion in HREE, and weak negative Eu （δEu=0.9～0.4） auanomaly can be observed; and most samples fall into the extent of adakite on （La/ Yb）N-YbN and Sr/Y-Y diagrams. Therefore, the discovery of the adakitic rocks have great significance for the study on Late Paleozoic tectonic evolution of Qinling orogenic belt.

作者邱庆伦龚全胜卢书伟柳生祥

机构地区河南省地质调查院甘肃省地矿局第三地勘院

出处《甘肃地质》 2008年第3期6-12,共7页 Gansu Geology

关键词埃达克岩花岗岩类岩石地球化学西秦岭甘肃夏河 adakitic rock granitoids geochemistry West Qinling Xiahe County of Gansu Province

分类号 P588.12 [天文地球—岩石学]

引文网络
相关文献

参考文献40

1Defant M J, Drummond M S. Derivation of some modern arc magmas by melting of young subducted lithosphere [J]. Nature, 1990,34:662-665.
2Peacock S M, Rusher T, Thompson A B. Partial melting of subducting oceanic crust [J]. Earth Planet Science Letter, 1994,121:224-227.
3Gutscher M A, Maury R, Eissen J P, et al. Can slab melting be caused by flat subduction [J]. Geology, 2000,28:535-538.
4Beate B, Monzier M, Spikings R, et al. Mio-Pliocene adakite generation related to flat subduction in southern Ecuador: the Quimsacocha volcanic center [J]. Earth Planet Science Letter, 2001,192:561-570.
5Atherton M P, Petord N. Generation of sodium-rich magmas from newly underplated basaltic crust [J]. Nature, 1993,362:144-146.
6Muir R G, Weaver S D, Bradshaw J D, et al. Geochemistry of the Cretaceous Separation Point batholiths, New Zealand: granitoid magmas formed by melting of mafic lithosphere [J]. Geol Soc, 1995,152:689-701.
7Xu J F, Shinjo R, Defant M J, et al. Origin of Mesozoic adakitic intrusive rocks in the Ningzhen area of east China: partial melting of delaminated lower continental crust [J]. Geology, 2002,30:1111-1114.
8Gao S, Rudnick R L, Yuan H L, et al. Recycling lower continental crust in the North China craton [J]. Nature, 2004, 432: 892-897.
9Wang Q, Xu J F, Jian P, et al. Petrogenesis of adakitic porphyries in an extensional tectonic setting, Dexing, South China: implications for the genesis of porphyry copper mineralization [J]. Petrol, 2006,47:119-144.
10薛怀民,董树文,简平.大别山造山带前陆阳新二长质侵入体的矿物化学、地球化学与锆石SHRIMP定年[J].中国科学（D辑）,2006,36(2):133-142. 被引量：24