Volcanic ash in Holocene valley deposits and its chronostratigraphic implication, Banks Peninsula, Canterbury, New Zealand.

Abstract

Two peaks of volcanic glass are found in Motukarara Valley, an enclosed valley on the western flanks of Banks Peninsula, Canterbury, New Zealand. The age and provenance of this tephra needed to be determined as only one Late Quaternary tephra was known to be present in South Island, New Zealand. This is the Kawakawa Tephra of 25.45 cal ka BP (Vandergoes et al., 2011). The presence of other primary airfall tephra in the study area, and thus South Island, could have major implications for correlation, validation of dating, chronostratigraphy and the understanding of geomorphic processes based on Kawakawa Tephra. This thesis reports on the results of the tephra research and the accompanying environmental analysis that are used to identify the cryptotephra and to reconstruct the depositional environment and a chronology for Motukarara Valley.