Intra-conference Tour Day 1: Hamilton–Raglan–Hamilton

Abstract

Today's trip to the Raglan district, western North Island, is primarily an introduction to (1) the Alexandra Volcanics, a group of chiefly basaltic deposits of Plio-Pleistocene age, and (2) the Kauroa and Hamilton Ash formations, two groups of weathered, predominantly rhyolitic, tephra beds of Plio-Pleistocene age that, in places, are intercalated with Alexandra Volcanics. Buried paleosols are associated with both the Alexandra and Kauroa/Hamilton deposits. We plan on spending around half the day at one site - Stop 5 - on the Karioi edifice on the west coast, just south of Raglan (Figs. 1.1, 1.5). Here we will examine, in a relaxed and informal manner, outcrops in and near Te Toto amphitheatre and gorge, a critical locality for understanding the stratigraphic succession and petrologic evolution of Karioi (see Fig. 1.9 below).