摘要
利用三维深地震测深技术 ,研究了长白山天池火山的岩浆系统 .结果表明 ,以低P波速度为主要特征的长白山天池火山岩浆系统在地壳范围内可分为 3个深度层次 :在 9～ 15km深度 ,岩浆系统分布的主要特征是范围广、尺度大、近南北走向 ,是地壳内储存岩浆的主要位置 ;自 15km深度以下直至下地壳 ,其分布横向尺度较小 ,显示出岩浆自上地幔侵入地壳的“痕迹” ,这也意味着长白山天池火山的岩浆系统极有可能延伸到上地幔 ,或更深 ;在地壳浅部 ,深度小于 8～ 9km范围内 ,岩浆的分布范围更小一些 ,集中在天池火山口稍偏北的南北方向上 .如果说低P波速度与岩浆系统关联的话 ,那么它反映出这部分岩浆仍然处于较高温度状态 .从这个意义上讲 ,长白山天池火山的岩浆系统至少不是“残留”的 ,或者说是处于“活动”
The magma system of Changbaishan Tianchi volcano is studied with three-dimensional deep seismic sounding (DSS) technique. The results show that the magma system of Changbaishan Tianchi volcanic region, mainly characterized by low velocity of P wave, can be divided into three parts in terms of depth. At the depth range of 9～15 km, the distribution of the magma system is characterized by extensiveness, large scale and near-SN orientation. This layer is the major place for magma storage. From the depth of 15 km down to the lower crust, it is characterized by small lateral scale, which indicates the ″trace″ of magma intrusion from the upper mantle into the crust, and also implies that the magma system most probably extends to the upper mantle, or even deeper. In the shallow crust (less than 8～9 km deep), the range of magma distribution is even smaller, centering on an SN-oriented area just north of the Tianchi crater. If low velocity of P wave is related to the magma system, it then reflects that the magma here is still in a state of relatively high temperature. In this sense, the magma system of Changbaishan Tianchi volcanic region is at least not ″remains″, in other words, it is in a ″active″ state.
出处
《地震学报》
CSCD
北大核心
2002年第2期135-143,共9页
Acta Seismologica Sinica
基金
中国地震局"九五"重点项目 (95 11 0 2 0 1)资助
