lithophile elements
1.The ores, ore-hosting carbonate rocks and clastic rocks including shale, silt limestone and pelitic siltstone all show distinct trace elemental distribution patterns. Ore samples of the upper ore-body are enriched in transitional elements like Ti, V, Cr, Mn, Co and Ni, immobile elements like Zr and Hf, as well as large ion lithophile elements like Sr and Pb, but are depleted in mobile elements such as Na, K, Rb, Ba and immobile elements such as Nb, Th.
2.Geochemical analysis demonstrates that the ore-bearing porphyries of the copper belt belong to the shoshonite-high-K calc-alkaline rock series and are characterized by enrichment of large ion lithophile elements (LILE) such as Rb, K, Sr and Pb and depletion of high field strength elements (HFSE) such as Nb, Ta and Ti. These features are similar to those of the ore-bearing porphyries of the Gangdise porphyry copper belt.
3.The diorites from Laiwu and Yinan have high Mg # (0.45～0.69)and Cr contents(up to278μg /g),and are rich in large ion lithophile elements(LILE)and depleted in high strength field e lements(HFSE). They compositionally resemble the late Archaean high-Mg diorites from Superior Province in North America and magnesian andesites in modern subduction zones.
4.Alkali-rich porphyry is relatively enriched in large-ion lithophile elements(K,Rb and Ba)and de - pleted in high-field strength elements(Nb,Ta,Ti and P)with a wider range of Nb/Y ratios and shows strong REE fractionation but no pronounced negative Eu anomaly — all these suggest that the magma source region un - derwent metasomatism and concentration of ancient subducted oceanic slab fluids and was injected by small streams of melts from the asthenosphere.
