| Summary: | The intrusion of the Storelv and Breivikbotn gabbros into metasediments on the island of Sørøy took place during the late stages of the first phase of Caledonian folding (F1). Both gabbros were then affected by almandine amphibolite facies regional metamorphism and accompanying granitization, the later being especially pronounced in the Storelv area. These events were followed by a second phase of folding (F2). Geochemical and ore-microscopic evidence shows certain characteristic differences between the two gabbroic masses. The Storelv gabbro contains higher amounts of TiO2, Rb, Zr, and Ba. It is rich in ilmenite, sphene and biotite. In the Breivikbotn gabbro, higher values for Cu, Cr and Ni have been measured, corresponding to widespread occurence of chalcpyrite and pentlandite. These differences partly reflect compositional variations of the respective local magmas, partly they can be ascribed to granitization. 35191
|
|---|