Carboniferous conodonts from rakaia terrane, East Otago, New Zealand

Abstract

Conodonts of Late Carboniferous (Pennsylvanian) age have been recovered from marble within a 100 m thick sequence of pure and impure marble, hematitic and chloritic slate, and metachert in Torlesse Supergroup semischist of the Rakaia Terrane. This sequence is exposed near Conical Peak in the Kakanui Mountains, Otago. Bands of marble contain microscopic metavolcanic clasts, quartz grains, and conodont elements in a groundmass of recrystallised calcite. The conodonts include at least three genera: Idiognathodus, Streptognathodus, and Gondolella, which together suggest an age of mid-Middle Pennsylvanian to latest Pennsylvanian. The red and green slate represents metamorphosed volcani-clastic beds, and grey slate represents background deposition. Bedding indicators, where present, are subparallel to the plane of cleavage development. No facing directions are recognised. Sandstone and mudstone have been metamorphosed to pumpellyite-bearing semischist of textural zone IIA. The calcareous, siliceous, and metavolcanic sedimentary rocks are interpreted as deep-sea turbidites, sourced from a topographic high, probably a seamount. Associated turbiditic sandstone and mudstone are of continental provenance. © 2006 Taylor & Francis Group, LLC.