Nickel in Buli Coastal Area, East Halmahera

Fragments of ultramafic, metamorphic, basalt and serpentine compose coastal sediments. These fragments derived from outcrops in hinterland as well as the coast. Existence of greywacke sandstone through microscopic observation in coastal sediments indicate deep sea derivation. Marine sediments also show almost the same composition with coastal sediments.Rock fragment abundances of ultramafic (10-47%), serpentine (12-24%) and metamorphic (3-12%) in stream and coastal sediments which have direct relation with the presence of nickel metal in the research area were resulted from petrographic analyses. While mineralographic analyses of heavy mineral concentrate from wooden pan show the existence of ferro nickel (Fe-Ni) and nickeline (Ni-As) in coastal and stream sediments. XRF analyses show nickel contents in seabed sediments 0.0140 to 0.793 %, chromite 0.0179 to 0.1128% and iron 1.2 to 6.85%. Coastal water nickel distribution is controlled by local trapped waves in Buli Bay that excite by equatorial Pacific Ocean waves propagate westward. Nickel occurrences in marine sediments would be an interesting further research.