Geology, petrology and age determination of Archaean-Proterozoic basement rocks of western Uganda

该项目旨在评估鲁文佐里山脉的隆起与托罗-安科勒火山区火山活动的产生之间的关系，方法是加深我们对火山岩和火山岩中超镁铁质结核的产生的了解。火山岩包括一种不寻常的钾质碱性火成岩，称为kamafuridae，可以解释为云母和富含单斜辉石的地幔组合的部分熔融，类似于在火山岩中发现的捕虏体。Sr、Nd和Os的同位素将用于评估地壳和岩石圈地幔的吸收，从而评估可能存在于地壳或地幔岩浆房中。Re-Os的发现将进一步揭示熔融地幔的性质，即软流圈或老岩石圈及其富集程度。岩石学和矿物化学特征的云母和单斜辉石轴承包体将确定这些岩石是来自地幔包体或壳堆晶的钾霞辉长岩。如果是地幔包体，则利用矿物化学（包括微量元素）来研究它们是橄榄岩普遍交代的结果还是局限于脉中。普遍的地幔交代作用已被提出在这一地区，导致岩石圈的体积大的增加-一个可能的原因Rwenzoris隆起。

This project aims to assess the relationship of the uplift of the Rwenzori mountains to the generation of volcanism in the Toro Ankole volcanic field by improving our understanding of the generation of the volcanics and of the ultramafic nodules within them. The volcanics comprise an unusual type of potassic alkaline igneous rock known as kamafugite that may be explained by partial melting of mica and clinopyroxene-rich mantle assemblages similar to those found as xenoliths within the volcanics. Isotopes of Sr, Nd and Os will be used to assess the uptake of crust and lithospheric mantle and therefore the possible residence in crustal or mantle magma chambers. Re-Os will shed further light on the nature of the mantle that melted, namely asthenosphere or old lithosphere and the extent of its enrichment. Petrological and mineral chemical characterization of the mica- and clinopyroxenebearing xenoliths will ascertain whether these rocks are xenoliths from the mantle or crustal cumulates from the kamafugites. If mantle xenoliths, the mineral chemistry, including trace elements, will be used to investigate whether they are the result of pervasive metasomatism of peridotite or are restricted to veins. Pervasive metasomatism of the mantle has been proposed in this area to result in a large volume increase in the lithosphere - a possible reason for the uplift of the Rwenzoris.