Comparative Studies of the Petrochemistry of S n– W ‐Mineralized Granitoids: Continent vs. Island Arc

Granitic rocks obtained during field excursions of the famed mineralized regions of the E rzgebirge, G ermany (mainly tin‐bearing), and S outh C hina (mainly tungsten‐bearing) have been geochemically analyzed and their results are compared with similar (mainly tungsten‐bearing) granites in the island‐arc setting of S outhwest J apan. The studied granitoids all belong to the ilmenite‐series. The collision‐related Erzgebirge granitoids are rich in K 2 O and P 2 O 5 , have high A/CNK ratios (1.11–1.24, i.e. S type), but are also high in G a/ A l ratio (i.e., having some A‐type characteristics). In S outh C hina, the X ihuashan granites, in contrast, are very low in P 2 O 5 , and have A/CNK slightly above 1.0 (1.01–1.05), indicative of I type granites. The ( S n‐) W‐related granites of southwest J apan have similarly low P 2 O 5 and A/CNK ratios, indicative also of I‐type. Both in the X ihuashan and southwest J apan, the tungsten‐related granites have high whole‐rock δ 18 O values implying involvement of W ‐rich crustal rocks. S n and W contents of the unaltered granites are lowest in the island‐arc setting where the related S n– W deposits are smallest in size relative to the collision and continental margin settings of the E rzgebirge and S outh C hina.