Some Miocene Stratigraphy and Paleontology - the Tongaporutuan Stage

Abstract

Seven Sections of Tongaporutuan (Upper Miocene) marine strata from the North Island and the northern part of the South Island were studied. Stratigraphic columns are given for each, and the type section is discussed in detail. From the seven sections a total of 167 foraminiferal samples were studied, and the distribution of species in 146 samples is shown in range charts. In all 336 species are recorded, of which 253 species occur in the type section. The systematics of 151 species from the type section, and 5 important species found only in other section are discussed. A total of 172 species are illustrated, and the following 9 new species are described: Martinottiella clarae, M. massami, Sigmoilopsis gavini, Spiroloculina kennetti, Bulimina vellai, Bolivina mitcheli, B. watti, B. petiae, and Cibicides finlayi. The biostratigraphy of the pelagic Family Globigerinidae and benthonic species are discussed. The Globigerinidae delimit three zones in Middle Miocene to Pliocene strata, but give no subdivision within the interval in which benthonic species distinguish the Waiauan, Tongaporutuan and Kapitean stages. Positive evidence of the Waiauan Stage was found in only one of the sections examined. The presently accepted subdivision of the Tongaporutuan into Lower, Middle and Upper on benthonic species was found to be broadly but not universally applicable. Resurrection of the Urenuian stage is not justified, and the separation of the Kapitean Stage is questioned because its two most important "key" foraminifera were found to extend down into Tongaporutuan Strata.