The Bingo carbonatite-ijolite-nepheline syenite complex, Zaire: geology, petrography, mineralogy and petrochemistry

摘要: Abstract The Bingo complex, on which little information has been published heretofore, is located in northeastern Zaire, 30 km west of the western branch East African rift. Although outcrop poor, fresh float enabled construction a geological map showing that intrusion consists ijolites cut and net-veined by nepheline sodalite syenites. include wollastonite-bearing varieties while some feldspathic; urtite also occurs. Calcite carbonatites underline 8 2 fenites are present. rocks described petrographically microprobe analyses most mineral phases, including rare gotzenite, given. pyroxenes define complete series terms diopside-hedenbergite-aegirine range from sodic diopside/hedenbergite to aegirine-augite ijolite pyroxene cores rims with aegirine presence gotzenite eudialyte attests high peralkalinity analyses, many trace elements, igneous silicate three As typical for intrusions this type, there considerable incoherance chemical data rocks, but they do give evidence continuous syenites, which, together data, taken indicate fractionation series. There no direct genetic relationship between carbonatite rocks.