Oxygen isotope composition of phenocrysts from Tristan da Cunha and Gough Island lavas: variation with fractional crystallization and evidence for assimilation
Oxygen isotope composition of phenocrysts from Tristan da Cunha and Gough Island lavas: variation with fractional crystallization and evidence for assimilation
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DOI：
10.1007/s004100050015
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发表时间：
2000-02-01
影响因子：
3.5
通讯作者：
le Roex, AP
中科院分区：
文献类型：
--
作者：
Harris, C;Smith, HS;le Roex, AP
我们测量了特里斯坦-达库尼亚和戈夫岛火山熔岩中主要斑晶（橄榄石、单斜辉石和斜长石）的δ（18）O值。这些岛屿，这是从同一地幔柱的结果，有丰富的放射性同位素比，因此，氧同位素的签名是不同于MORB的主要候选人。咳嗽熔岩中橄榄石、辉石和长石的δ（18）O值之间的一致差异表明，基性戈夫岛熔岩中的斑晶处于氧同位素平衡状态。含SiO2熔岩中的橄榄石
We have measured the delta(18)O values of the major phenocrysts (olivine, clinopyroxene and plagioclase) present in lavas from Tristan da Cunha and Gough Island. These islands, which result from the same mantle plume, have enriched radiogenic isotope ratios and are, therefore, prime candidates for an oxygen isotope signature that is distinct from that of MORB. Consistent differences between the delta(18)O values of olivine, pyroxene and feldspar in the cough lavas show that the phenocrysts in the mafic Gough Island lavas are in oxygen isotope equilibrium. The olivines in lavas with SiO2