Part 4. Plate boundary evolution in the Solomons region: Ophiolite basement complex in a fractured, island chain, Santa Isabel, British Solomon Islands

Abstract

As part of a continuing programme involving the structural, petrological, and geochemical evolution of the British Solomon Islands, attention has now centred, among other islands, on Santa Isabel, where a well developed basement ophiolite sequence is exposed. Further work in the area will involve the geochemical relationships between the various members of the ophiolite basement. The Solomons lies within Suess's outer 1st Australian Arc, now regarded as the margin between the India and Pacific lithospheric plates (Le Pichon, 1968) and have been termed a composite, fractured island chain (Coleman and Hackman, 1974). The Group comprises a double en echelon chain of islands, which is believed to reflect a system of basins and anticlinal horsts now progressively offset by sinistral shear (Carey, 1968; Krause, 1967; Hackman, 1973). Five Provinces were originally recognised in the region (Coleman, 1965) and these were subsequently amended to four (Hackman, 1973).