Epithermal Gold-Silver Deposits of the Hauraki Goldfield, New Zealand: An Introduction

Abstract

The five papers that follow describe diverse aspects of epithermal gold-silver deposits and genetically related hydrothermal systems in the Hauraki goldfield on the Coromandel peninsula of the North Island of New Zealand (Fig. 1). The Hauraki goldfield contains more than 50 Miocene and Pliocene epithermal Au-Ag deposits and several porphyry Cu-Au-Mo occurrences in a 200-km-long by 40-km-wide north-south–trending belt (Fig. 1C; Christie et al., 2007). Production from these deposits between 1862 and 2009 totaled approx. 335,000 kg (10.8 Moz) of Au and 1.6 million kg (51.4 Moz) of Ag (Mauk et al., 2011). The epithermal deposits are related to subaerial hydrothermal systems hosted in rocks of the early Miocene to late Pliocene (~18–1.9 Ma) Coromandel volcanic zone (Skinner, 1986). Fig 1 A and B. Location of the Hauraki goldfield and Coromandel volcanic zone. C. Regional geology, mineral deposits, and provinces. D. Structural features of the Coromandel volcanic zone and Hauraki goldfield. Black open box in C and D shows location of Waihi-Waitekauri geophysical study area of Morrell et al. (2011). Figure modified from Christie et al. (2007). Placer gold was first discovered near Coromandel township in 1852, but because of the small size of these placers, little mining activity occurred until the discovery of Au-bearing quartz veins in 1861 at the site of the Kapanga mine (Fig. 1C). Prospecting elsewhere on the Coromandel peninsula resulted in the opening of mines at Thames in 1865, Karangahake in 1875, and Waihi (Martha) in 1878. The major period of gold mining ended with the closure of the underground Martha mine at Waihi in 1952. Total production during this period was more than 250,000 kg (8.0 Moz) of Au and 1,100,000 kg (35.3 Moz) of Ag (Christie et al., 2007). Higher gold prices in the 1980s led to renewed exploration, and the …