The base of a sheeted dyke complex, Oman ophiolite: implications for magma chambers at oceanic spreading axes

The sheeted dyke complex in the Maydan syncline area of the Oman ophiolite was formed during a single sea-floor spreading episode. In some areas, individual dykes from this sheeted dyke complex have been seen to root in the high-level gabbro, and others are truncated by high-level gabbro, diorite and trondhjemite. However, elsewhere dykes penetrate laterally into the layered part of the plutonic sequence. This situation suggests that active magma chambers and zones of dyke injection were discontinuous along the spreading axis at any one time.