陆相火山岩区火山机构的识别——以浙江新昌东茗复活破火山为例

    Identification of the volcanic edifice in continental volcanic areas: A case study of the Dongming resurgent caldera in Xinchang, Zhejiang Province

    • 摘要: 火山机构识别与解剖是陆相火山岩区填图的核心,以浙江新昌东茗复活破火山为例, 探讨陆相火山岩区火山机构的调查与研究方法。该破火山以磕山-乌龟山-大尖岗火山通道为中心,火山-沉积岩层围斜内倾分布,环状、放射状断裂及岩脉发育。在综合运用遥感解译、地球物理和地球化学及区域地质调查的基础上,查明了火山机构类型、形态、范围及其喷发产物特征和时空分布格局,并以此作为恢复火山喷发历史及确定火山机构演化的重要手段。结果显示,东茗复活破火山先后经历了正常沉积夹小规模喷发、大规模喷发、破火山口沉陷、晚期复活4个演化阶段。研究表明,火山通道的厘定、火山岩性及岩相特征、火山喷发产物分布及范围、环状断裂等是识别火山机构,进而恢复火山活动过程的关键要素。

       

      Abstract: The identification and anatomy of volcanic edifice is the key of continental volcanic mapping.Taking the Dongming resurgent caldera in Cretaceous Xinchang basin of Zhejiang Province as an example, the investigation method of volcanic edifice in continental volcanic area is discussed.The caldera is centered on the Zhushan-Guozhan-Dajiangang volcanic channel, and the inward-dipping volcano-sedimentary strata are cut by annular and radial faults, with developed dikes.Based on the comprehensive applications of remote sensing interpretation, geophysics, geochemistry and regional geological survey, the types, forms and ranges of volcanic edifice, characteristics of eruptive products and their spatial and temporal distribution patterns have been identified, which can be used as an important means to recover the history of volcanic eruptions and determine the evolution of volcanic edifice.The evolutional history of Dongming resurgent caldera can be divided into four stages: normal sedimentation accompanied with small eruption, major eruption, crater collapse and resurgence.The results show that the determination of volcanic vent, volcanic lithofacies and lithology, the distribution and spatial-temporal variations of eruptive products and ring faults are the key factors to identify the volcanic edifice and recover the volcanic history.

       

    /

    返回文章
    返回