Pliocene and Quaternary geology of Mana Island (Note)

Abstract

Abstract Mana Island, off the south-west coast of the North Island, is capped by the Mana Surface which dips south-east at about 2°. This dip is considered to be tectonic in origin. The surface, considered to be a marine abrasion platform, has no overlying deposits except late Quaternary loesses. No continuity with mainland surfaces can be demonstrated, but correlation with the Quartz Hill Surface, of probable early Pliocene age, is thought possible. Below the Mana Surface seven marine benches and gravel terraces have restricted distribution. Such benches and terraces are considered to have formed during successive interglacials. Terrestrial deposits include a deeply weathered post-Mana Surface fanglomerate and, in the east, a Holocene fluvial terrace.