Stratigraphy of Hutchinsonian and Awamoan Stages (Lower Miocene) at Target Gully, Oamaru, New Zealand

Abstract

Globigerinoides trilobus trilobus (Reuss) and Globorotalia zealandica zealandica Hornibrook, previously considered to appear in the Awamoan Stage, are reported from Hutchinsonian beds at Target Gully, Oamaru. Trends in the lineages of Haeuslerella pukeuriensis Parr and Globigerinoides trilobus trilobus (Reuss) are used to estimate relationships between the sequence at Target Gully and the name bearers of Otaian, Hutchinsonian, and Awamoan Stages. The “Pachymagas” shellbed at Hutchinson's Quarry lies at, or slightly above the Otaian-Hutchinsonian boundary; higher units of the Hutchinsonian are present at Target Gully. The name bearer for the Awamoan Stage may correlate with beds beneath Target Gully Shellbed, the base of the stage by original designation.