Geochemistry of the Neoarchaean Volcanic Rocks of the Kilimafedha Greenstone Belt, Northeastern Tanzania

Figure 11

Nb/Yb-Zr/Yb diagram (after Pearce and Peate, [26]) for the Kilimafedha tholeiitic basalts (filled triangles) and intermediate volcanic rocks (open squares). The tholeiitic basalt samples plot around the NMORB field tending towards the mantle enrichment direction within the MORB array suggestive of metasomatism by aqueous fluid. The intermediate rocks plot just above the EMORB tending to higher Zr values illustrating input of the HFSE from the subducted slab. NMORB, EMORB, and OIB data are from Sun and McDonough [23].