Sediment discharge to the ocean from small mountainous rivers: The New Guinea example

Abstract

The small mountainous rivers draining the large island of New Guinea (area = 800,000 km²) discharge approximately 1.7 × 10⁹ t of sediment annually, about the same as the combined estimated loads of rivers draining North America. Sediment yields are particularly high for rivers that drain the high mountains of eastern New Guinea, where drainage basins are high and drainage areas small. Owing to the generally narrow (<10 km wide) shelf off eastern New Guinea, much of the fluvial sediment may escape directly to the adjacent deep sea, as evidenced by the presence of sediment-filled trenches. In contrast, many of the rivers draining the south—central part of the island discharge onto a fairly broad shelf, where much of the sediment presumably remains, perhaps as prograding mud wedges.