Delayed fractionation of basaltic lavas
Delayed fractionation of basaltic lavas
复制标题
玄武岩熔岩的延迟分馏
DOI：
10.1007/bf00372360
复制
发表时间：
1988
影响因子：
3.5
通讯作者：
D. James
中科院分区：
文献类型：
--
作者：
S. Maaløe;R. Pedersen;D. James
来自扬马延和夏威夷的玄武质熔岩的斑晶核显示出一系列的成分。斑晶的结构特征也各不相同，自形斑晶和骨架斑晶都存在于同一薄片中。显然，玄武岩浆在分离之前在50-200° C的温度区间内经历了结晶。因此，玄武质熔岩的馏分是斑晶组合的平均组成，而不是液相线组成。这种类型的分馏被称为延迟分馏。认为大多数拉斑玄武岩和碱性玄武质熔岩经历了延迟分馏作用。
The phenocryst cores of the basaltic lavas from Jan Mayen and Hawaii display a range in compositions. The textural features of the phenocrysts also vary, both euhedral and skeletal phenocrysts are present in the same thin section. Apparently the basaltic magmas underwent crystallization within a temperature interval of 50–200° C before they became fractionated. The fractionates of basaltic lavas are therefore average compositions of the phenocryst assemblages rather than liquidus compositions. This type of fractionation is called delayed fractionation. It is considered that most tholeiitic and alkalic basaltic lavas undergo delayed fractionation.