摘要
大兴安岭北部伊列克得组玄武岩类具有富碱 (K2 O+ Na2 O>6 .37% )、高 K2 O(2 .6 2 %～ 3.11% ) ,高 K2 O/ Na2 O比值 (0 .7～ 0 .8)和 Th/ Ta、Ce/ Nb、Ta/ Nb比值、以及强烈富集大离子亲石元素 (L IL E)和轻稀土元素 (L REE)的特征 ,属于钾玄质系列。低 Sr/ Nd比值 (13～ 17.5 )的特征类似于洋岛玄武岩 ,但其 Ta/ Hf,Th/ Ta比值特征及与 A型花岗岩共生等特征表明 ,钾玄岩形成于板内环境 ,考虑到各种因素可能产于大陆裂谷。钾玄质岩浆可能是富集的中生代岩石圈地幔
The basalts of early Cretaceous Yiliekede Formation belong to shoshonitic series characterized by rich alkaline (K 2O+Na 2O>6.37%), high K 2O(2.62%~3.11%), high ratios of K 2O/Na 2O, Th/Ta, Ce/Nb and Ta/Nb, and strongly enriched in LILE and LREE. The low Sr/Nd ratios (13~17.5) of basalts are similar to those of OIB, but the characteristics of Ta/Hf, Th/Ta and co existance with the A type granites suggest that the shoshonites were formed under the condition of intraplate setting, most likely continental rift.The shoshonitic magma is considered to be the partial melting product of phlogopite bearing lherzolite in the enriched Mesozoic lithospheric mantle.
出处
《矿物岩石》
CAS
CSCD
北大核心
2000年第3期14-18,共5页
Mineralogy and Petrology
基金
国家自然科学基金!(49972 0 2 7)
国家杰出青年科学基金! (4972 5 30 9)
关键词
钾玄岩
地球化学
早白垩世
大陆裂谷
玄武岩
shoshonite
Geochemistry
Early Cretaceous
continental rifting
Daxing'anling
