摘要
新疆三大山系均有新生代火山岩,其中南部西昆仑、阿尔金山及天山托云等地的新生代火山岩比较发育,在新疆东北部地区的阿尔泰哈拉乔拉一带也发育新生代的陆内喷发火山岩。这套火山岩虽然面积不是很大,但具有大陆溢流玄武岩的特点。在地球化学上也具有典型热点成因洋岛玄武岩或其它地幔柱成因玄武岩的特点,如TiO2含量高大于2%、轻稀土元素和不相容元素显著富集等。表明新疆北部特别是阿尔泰造山带东部演化到新生代以后,有向裂陷拉张方向演化的趋势,标志着一个新的大地构造演化阶段的到来。
Cenozoic volcanic rocks exist in the Kunlun,Tianshan and Altai mountain s,both of those in the Kunlun and Tianshan mountains have been known to geologists,while the Cenozoic basalts in the Halaqiaola area,East Altai,have not been studied by now.This paper presents the contents of major elements,minor elements,and rare earth elements in the basalts fr om Halaqiaola.This series of Cenozoic volcanic rocks has obvio us features of continental flood basalts,even its distribution is not widely.It’s high content of TiO 2 (greater than 2wt%),high content of large-ion lithophi le elements and high fieldstrength ele ments such as Nb,Ta,Zr and Hf,and its rare earth elements geochemistry show an environment of rifting,but at its initial stage of r ift.Diagram analysis proved the Halaqiaola basalts to be originated from a mantle plume or part of the Altai-Baikal Lake mantle plume,which has produced the deepest rift lake in the Eurasian continent .The eruption of the Halaqiaola Cenozoic continental fl ood basalts may mark the beginning of a new episode of continental evolution in the Altai mountains.
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2001年第3期282-289,共8页
Geotectonica et Metallogenia
基金
国家305项目96-915-01-02
国家重点基础研究项目G1999043203资助.
