大兴安岭西坡中生代火山岩形成机制

依据火山喷发特点、火山岩岩石组合及火山岩的同位素年代学证据,大兴安岭西坡地区发育的大量中生代火山岩可分为三个放回,自早而晚依次为：晚侏罗世的塔木兰沟族回、上库力旋回和早白垩世的伊列克得旋回。不同旋回火山岩具有不同的地质、地球化学特征。在岩浆起源、源区性质和演化过程等方面,不同族回火山岩既有相似之处,也存在明显差别。火山岩为深部作用和过程的产物,对其形成机制的研究,有助于理解本区中生代发生的剧烈的火山岩浆作用和成矿作用的构造背景及演化过程。

FORMING MECHANISM OF THE MESOZOIC VOLCANIC ROCKS ON THE WESTERN SLOPE OF DAXINGANLING

There exist large numbers of Mesozoic volcanic rocks on the western slope of DaXinggan Ling. Theserocks can be divided into three cycles: Tamulangou, Shangkuli and Yiliekede, respectively, according tovolcanic eruption, rock assemblage and isotopic age. Volcanic rocks of each cycle have their own features,reflecting different geneses. Based on the chemical data of Mesozoic volcanic rocks, the paper discusses theirorigin, nature of the source region and magma evolution and concludes that all materials forming the volcanic rocks come from deep mantle. The information about the genesis of the volcanic rocks is important forunderstanding the forming process of mineral deposits closely related with these rocks.