BRIEF GEOLOGY FOR HQ-P20657 and HQ-P2068
Chunya Goldfield which is part of Lupa Goldfield is one of the lesser understood Goldfields in Tanzania. The ore deposit are hosted by Early Proterozoic granite and gneissic rocks.
It underlain by gneisses,migmatites and later intrusive. Meta basite bodies and magnetite-quartzite inclusions probably represent remnants of volcanic secondary sedimentary sequences which include mafic volcanics and magnetite bearing BIF.
Granodiorite and diorite intrusions cut these rocks,particularly in the Northernpart of the area of the area.Potassium and sodic alteration of gneiss occurs near the intrusive.Metarmorhic grades within the Lupa Goldfields are greenschists t olower amphibolite facies,incontrast to much Higher grades of the surrounding terrrane of Ubendian system.
MINERALIZATION;
Gold in Chunya Goldfield is in both lode and secondary deposits, with the bulk of historic production from secondary mineralization, that is from stream placers ,hillside elluvial deposit and from weathered rubble zones above or adjacent to quartz lodes.
Lodes in Chunya are typically within shear zones.
The most productive of these has been the Saza shear zones, where ore bodies consist of steeply dipping lenticular quartz bodies.
These Low sulphides lodes consist of quartz with trace of base metal sulphides, molybnite, with sparse to abundant pyrite. The ore is free milling with gold/silver ratio ranging from1;1 to 2:1
Ore occurs in distinct shoots, generally up to 1.5m wide, but occasionally it occurs up to 20m. |
