New Caledonia and the Loyalty Islands

Introduction

New Caledonia (area, 19,800 sq km) has a coastline about 2,254 km long. It is a mountainous island (rising to 1,629 mon Mont Panié) consisting mainly of crystalline schists with peridotite and serpentine rock. The east coast is generally steep, with only minor plains around river mouths, several of which open into deep rias; the west coast has more extensive plains, backed by a hilly hinterland, with numerous promontories and islands, and intervening embayments into which deltas have been built. Open-cast mining of nickel is extensive in the lateritised peridotite highlands of New Caledonia, and has added red clay, sand, gravel, and boulders to the natural sediment loads of many of the rivers, eventually accelerating the infilling of estuaries, the progradation of deltas, and the shallowing of nearshore waters. Evidence of such changes has been obtained by comparing nineteenth-century maps and charts with air photographs taken in 1954 and 1976 (Bird et al. 1984)....