Pre-conference tephra data workshop: Hands-on session II: Tephra excursion, Okareka loop road (29 January 2023)

Abstract

General stratigraphy of Okareka Loop Road section. The following units are evident in the sequence from the base upwards: (1) early tephras (Te Rere, 25.1 cal ka; Okareka, 23.5 cal ka) and thin interbedded loess within the remnant top of a small, buried hill-top at the base of the sequence; (2) the buried hill itself, the formation of which represents a period of erosion that occurred during the last glacial period, and remnants of a (reworked?) tephra draping the (paleo)hillslope (Rerewhakaaitu, 17.6 cal ka); (3) the thick (~4.5 m), bedded pumice lapilli tephra (with lithics) mantling the hill (Rotorua, 15.6 cal ka), the top of which is pedogenically modified to form a distinct orange soil (this orange soil material is evident throughout Rotorua basin and in road cuttings such as along SH 5 to the west of Rotorua); and (4) at least four younger tephras and soil horizons overlying the buried soil on the Rotorua tephra: Waiohau (14.0 cal ka), Rotomā (9.4 cal ka), Kaharoa (c. 1314 ± 10 CE/AD), and Rotomahana Mud (of the Tarawera eruption, 10 June 1886).