PGE contents of parental magmas to the Bushveld Complex:were they enriched or not?
The Bushveld Complex is the largest depositary of Platinum Group Elements (PGE) in the world but the origin of the metals remains poorly understood.The PGE contents of the parental magmas are also not known with certainty as the ore zones formed by mixing of magmas that contained only ppb levels of PGE.The compositions of the magmas that gave rise to the Bushveld Complex are enigmatic and undoubtedly formed from multiple sources.Up to present the only approximations of the parental magma compositions and their PGE contents are from marginal sills that intruded the country rocks of the Bushveld Complex.This work is based on the study of a series of deep drill cores in the eastern Bushveld Complex that intersected the Lower Zone,and in one case,penetrated the country rock revealing,for the first time,a chilled sequence to the Bushveld Complex.This sequence contains true chills,quench textures,spinifex and harrisitic textured rocks all of which preserve a high level of trapped parental liquid and even frozen liquid.This paper examines these occurrences from the aspects of parental magma compositions and their PGE contents.
A.H.Wilson
School of Geosciences,Wits University,Johannesburg,South Africa
国际会议
贵阳
英文
66-69
2012-06-16（万方平台首次上网日期，不代表论文的发表时间）