摘要
乌兰哈达火山群地处华北地块北缘内蒙地轴与边缘增生带的交接部位,晚第四纪玄武岩包括晚更新世和全新世2期。火山产物为玄武岩、玄武质熔结火山碎屑岩和松散火山渣,以玄武岩为主。Na2O＋K2O含量高达5.94%～8.34%,平均为7.55%;K2O/Na2O〈1（0.48～0.59）,属钠质碱性玄武岩。岩石化学和地球化学特征表明,玄武岩岩浆来自富集地幔,但经历了一定程度的分异及陆壳混染,为弱进化岩浆。晚更新世早期主要为碱性橄榄玄武岩,全新世主要为碱玄岩。玄武岩具大陆板内之属性,形成于大陆裂谷初期的构造环境。
Wulanhada volcano cluster is located at the intersection area between the Inner Mongolia Axis and its bordering accretion zone in the northern borderland of North China massif. The Late Quaternary includes the Late Pleistocene Epoch and the Holocene Epoch. The volcanic products are mainly basalt, together with basaltic welded pyroclastic rocks and loose cinders. With alkaline contents（ Na2 O ＋ K2O） of the basalts ranging from 5.94% to 8.34%（ 7.55% in average）,and K2 O / Na2 O from 0.48 to 0.59（ lower than 1）,it falls into the category of sodium-alkaline series.Chemical and geochemical characteristics indicate that the basaltic magma,to a certain degree of magmatic differentiation and crustal contamination,is of weak evolution,although it is generated from enriched mantle. The Late Pleistocene is mainly of alkaline-olivine basalts while the Holocene is of tephrite. With a continental intraplate origin,Wulanhada basalts were formed in an intraplate setting at the early stage of continental rifting.
出处
《地震地质》
EI
CSCD
北大核心
2016年第1期182-196,共15页
Seismology and Geology
基金
国家地震局公益性科研专项(200782713)
内蒙古国土资源厅地质遗迹保护专项(20071250)共同资助
关键词
碱性玄武岩
进化岩浆
裂谷初期
晚第四纪
乌兰哈达
alkali basalt
evolutional magma
early-stage rifting
late Quaternary
Wulanhada
