羌塘西北部松西地区康托组火山岩年龄及意义  

AGE AND SIGNIFICANCE FOR THE VOLCANIC ROCKS OF CANTOR FORMATION SONGXI REGION IN NORTHWEST OF QIANGTANG

作　　者：钟华明[1] 刘俊[2] 童劲松[2] 夏军[2] 鲁如魁[2] 

机构地区：[1]安徽工业经济职业技术学院地质系,安徽合肥230051 [2]安徽省地质调查院,安徽合肥230001

出　　处：《安徽地质》2008年第2期92-94,共3页Geology of Anhui

摘　　要：羌塘西北部松西地区沿断陷盆地发育一套中性—酸性火山岩及火山碎屑岩,主要岩性包括安山岩和英安岩,是青藏高原隆升阶段在藏北地区伸展拉张作用的产物。安山岩40Ar-39Ar同位素年龄为36.42±0.93Ma。结合区域资料认为松西地区火山活动时代为古近纪始新世晚期-渐新世早期。火山岩年龄的确定不但制约了新生代沉积地层的年代,同时也为藏北地区陆内拉张时代的确定提供了依据。A neutral - acidic volcanic rocks and volcaniclastic rocks were developed along the north-west rift basin of Qiangtang of Song Xi area, including the main lithologic andesite and dacite, is the products of stretching stage extension role of the uplift of the Qinghai-Tibet Plateau in northern Tibet region. Andesite isotope ^40Ar-^39Ar age is of 36.42 ± 0.93Ma, with information of the regional geological integration the era of ancient volcanic activity in Song Xi area is in late Eocene of Paleogene-early Oligocene. Volcanic age＇s determine not only restricted the formation age of Cenozoic sedimentary strata, but also provided a basis for the determination of stretching times of the intra continental in northern Tibet region

关 键 词：松西地区 火山岩 古近纪 同位素年龄 

分 类 号：P588.14[天文地球—岩石学]