volcanic cycle

The basic volcanic rocks of the first cycle belong to the alkali basalt magma series and those of the second and the third cycles the tholeiitic magma series.

第一旋回基性火山岩属碱性系列，第二、三旋回基性火山岩属拉斑玄武岩系列。

Taking Mesozoic volcanic rocks in Eastern Fujian as an example, the authors put forward a new cartographic unit of volcanic terrains ( volcanic cycle, volcano tectonic element and lithofacies assemblage), in which the volcano tectonic element is a basic cartographic unit.

以福建省东部中生代火山岩为例，提出以火山旋回-火山构造单元-岩相（组合）作为火山岩区的三级填图单位，其中火山构造单元为基本的填图单位。

This state is typically the last in the life cycle of an island, the first being volcanic and the second being an atoll.

珊瑚岛是岛屿形成过程中的第三个阶段。第一个阶段是火山活动形成岛屿，第二个阶段就是环礁岛。

Volcanic rocks of each cycle have their own features, reflecting different geneses.

不同旋回火山岩具有不同的地质、地球化学特征.