陆相火山岩区填图方法的实践——以浙江嵊州新生代玄武岩为例

从20世纪90年代以来,中国陆相火山岩区调查工作普遍采用"火山构造-火山岩相-火山岩性"三位一体的思路与工作方法。以浙江嵊州地区1∶5万区域地质调查工作为例,探讨了该方法在大面积新生代玄武岩区中的应用。系统的野外调查及研究显示,在新生代玄武岩区,遥感技术及新的影像图是火山岩区填图的关键,图像解译-野外验证的反复实践,是提高填图效果和质量的有效方法。在野外,特殊的地貌、爆发相的集块角砾岩及火山颈相的玄武玢岩往往指示了火山机构的中心;火山岩相、喷发间断是划分火山旋回的关键。火山机构、火山岩相、火山岩性的时间-空间变化是恢复古火山喷发历史的关键手段。

Practice of the mapping method in continental volcanic rocks outcrop area:A case study of Cenozoic basalt in Shengzhou, Zhejiang Province

The "volcanic structure-volcanic lithofacies-volcanic lithology" trinity mapping method has been wildly used in the continental volcanic rock outcrop area of China since the 1990s. This paper discussed the applicability of this mapping method in the 1:50000 Shengzhou geological mapping program for large outcrop area of Cenozoic basalts. According to field investigation and research work in the Cenozoic basalt area, the remote sensing technology and the new remote sensing images are the key factors of the volcanic rock area mapping. Image interpretation combined with field verification is one of the effective methods to improve the quality and effectiveness of the mapping. In the field, the special landscape and outcrops of eruption facies of breccias and volcanic neck facies of basalt porphyrite often indicate the central position of the volcano. Volcanic rock facies and eruption gaps are the key factors for the division of volcanic cycle. Volcanic edifice, volcanic lithofacies, volcanic lithology-space-time change are the key factors for restoration of ancient volcanic eruption histories.