第24卷第1期 2010年2月
现代地质 GEOSCIENCE
VoL 24Na.1 Feb. 2010
四川若尔盖地区西康群地球化学特征及其物源区
和古风化程度分析
白宪洲12，何明友"，王玉婷，杨学俊3
（1.成都理工大学核技术与自动化工程学院，四川成都610059；2.四川省地质调查院，四川成都610081）
摘要：通过对四川省若尔盖地区西康群砂泥岩的主量元素、微量元索和稀土元索进行综合研究，发现本区砂泥岩的 SiO2、P,Os、MnO与PAAS有相同的含量，高集Na,O、CaO，贫Al,O,、Fe,O,、MgO、K,O和TiO。微量元素W含量大大高于上地壳丰度，Nb和Ta含量大大低于上地壳丰度，而与下地壳丰度相当，Se的含量略低于上地壳丰度，造岩元素Sr略高于地壳丰度值。稀土元素总量相对较高，平均值为133.97×10-°，与地壳中的稀土元素总量112×10"较为接近。轻稀土元素相对于重稀土元索较为富集，具中等的负销异常，稀土配分曲线均显示比较一致的右倾的轻稀土富集的配分模式。由此认为其地球化学特征与大陆岛弧和被动大陆边缘沉积物相似。综合其他地质资料认为若尔盖地区西康群砂泥岩的物源区可能为康滇古陆。
关键词：若尔盖地区；三叠纪；地球化学：物源区；古风化；四川
中图分类号：P588.21
文献标志码：A
文章编号：10008527(2010)01=015107
OntheGeochemicalCharacteristics,ProvenanceandPaleoweathering DegreeofTriassicXikangGroupinRuoergaiAreainSichuanProvince
BAI Xian-zhou',2, HE Ming-you', WANG Yu-ting', YANG Xue-jun
(1, The Cllege of Applied Nuclear Technology and Automation Engineering, Chengdu Uitersity of Technology, Chengdu,
Sichuas 610059, China; 2. Sichuan lnstitute of Geological Surey, Chengdu, Sichuan 610081, China)
Abstract: Through a comprehensive study on the major elements, trace elements and rare earth elements of flu-vial sand of Triassic Xikang Group in Ruoergai area in Sichuan Province, this paper found that the fluvial sand of this area has the same contents of SiOz, P,O, and MnO as that in PAAS. It is enriched in Na,O, CaO and poored in Al,O,,Fe,O,Mg,K,O and TiO,.The content oftrace element W is far greater than the supra-crustal abundance. The contents of Nb and Ta are far lower than the supracrustal abundance, but it is about same as lower crustal abundance. The contents of Sc are lower than the supracrustal abundance. Petrogenic ele-ment Sr is a little higher than crustal abundance. The capacity of rare earth elements is relatively higher. The average value is 133. 97 × 10 -, which is close to 112 × 10 -° the capacity of rare earth elements in the crust. Light rare earth elements are richer than heavy rare earth elements. It has medium negative europium anomaly The distribution curves of rare earth elements show a consistent rightward declined light rare earth elements en-richment patterm. It is thought that its geochemical characteristics are similar with that of continental arc and passive continental margin sediment.Tosum upothergelogical data,it is concluded that Kangdian old land is a possible provenance region of fluvial sand of Triassic Xikang Group in Ruoergai area.
Key words; Ruoergai area; Triassic; geochemistry; provenance; paleoweathering; Sichuan
收稿日期：2009-07-13；改团日期：2009-12-18；责任编桃：楼亚儿。基金项目：中国地质调查局国土资源大调查项目（1212010510304)。
作者简介：白究洲，男，工程师，博士研究生，1975年出生，地球化学专业，主要从事矿床地球化学研究工作。
Email:baixianzhou163,com