Stratigraphy of Maruia and Matiri Formations in their type section (Trent stream, Matiri river, Murchison)

Abstract

The type section of the Maruia and Matiri Formations has been re-investigated. Maruia, Formation comprises the successive West Coast lithofacies usually mapped as Brunner, Island, Kaiata, Little Totara and Port Elizabeth Formations, and is, therefore upgraded to Maruia Group. Only the lower parts of Matiri Formation are exposed at the type locality. Basal Matiri lithofacies represent distal turbidites, slope-slump deposits and calcflysch, a generally redeposited sequence that accumulated in the newly forming Murchison depocentre during the Oligocene to lower Miocene. A description is given of the lithology, petrography and palaeontology of Maruia Group and Matiri Formation, environmental interpretations are suggested, and palaeogeographic conclusions drawn.