... differences in gray shadings are not easy to discern. The chapter on Northland contains one paper on halloysite clays, and a second on Hg- and Au-Ag–bearing epithermal sinter deposits north of Auckland. Next is the chapter on the Hauraki gold field, truly one of the best natural laboratories in the world...

..., fluid inclusions, and stable isotopes, and synthesized these data for the entire gold field. The papers in this volume represent recent studies of epithermal deposits in the Hauraki goldfield undertaken at the University of Auckland. The studies range from regional to deposit scale. Mauk et al...

... and Thames, which are the main bonanza-style veins in the Hauraki gold-field. The deposits are characterized by relatively high Au/Ag ratios and by veins filled with coarse comb or massive quartz. Arsenopyrite occurs in the Coromandel deposits and in deposits farther north. Adularia is absent (or rare...

... occurred just before the onset of Whitianga Group rhyolite volcanism at approximately 10 Ma. The greatest pulse of Au deposition in the Hauraki gold-field occurred between 6.9 and 6.0 Ma and was preceded from ca. 9 to 7 Ma by significant volcanism, including major ignimbrite eruptions and caldera...

...Mark P. Simpson; Michael F. Gazley; Alistair G.J. Stuart; Mark A. Pearce; Renee Birchall; Debra Chappell; Anthony B. Christie; Murray R. Stevens Abstract The Karangahake deposit is the third largest gold producer in the Hauraki goldfield, Coromandel, New Zealand. Production was mainly from...

...-southeast extension and normal dip-slip deformation. Strike-slip faulting is very rare and of only minor importance. This is in accordance with the fact that no major synmineralization strike-slip faulting has yet been rigorously demonstrated in the Hauraki gold-field. Instead, a tectonic framework...

.... Simpson M.P. Brathwaite R.L. Mauk J L. Simmons S.F. , 2007 , Epithermal Au-Ag and Related Deposits of the Hauraki Gold-field, Coromandel volcanic zone, New Zealand : Economic Geology , v. 102 , 785 – 816 . Conrad M.E. Petersen U. O’Neil J.R. , 1992 , Evolution...

.... 20 , p. 135 – 156 . Christie , 1982 , Fluid inclusions, stable isotopes and geochemistry of porphyry copper and epithermal vein deposits of the Hauraki gold-silver province, New Zealand : Ph.D. thesis , Wellington, Victoria , University of Wellington , 769 p. Christie A.B...

... ). The Favona deposit is in the southern part of the Hauraki goldfield (Fig. 1 ), a 200-km-long by 40-km-wide metallogenic province that contains the greatest concentration of precious metal deposits in New Zealand ( Brathwaite and Pirajno, 1993 ; Christie et al., 2007 ). Approximately 50 epithermal gold...

... and lies within the classic adularia-sericite epithermal gold-silver province of the Hauraki goldfield ( Christie et al., 2007 ). Hydrothermal activity in the Waihi-Waitekauri region occurred over a period of 0.8 m.y. ( Mauk et al., 2011 ) pervasively altering an area of approximately 65 km 2 , i.e., ~35...

...) and the Taupo Volcanic Zone (TVZ), and at the Waiotapu active geothermal area in the TVZ ( Fig. 1 ). Fig. 1. Location of the sample areas in North Island, New Zealand: Pine Sinter, Ohui and Luck at Last mine in the Hauraki Goldfield (Coromandel Volcanic Zone) and Gold Mine Hill and Waiotapu in the Taupo...

...Michael J. Begbie; K. Bernhard Spörli; Jeffrey L. Mauk Abstract Golden Cross, located in the Hauraki goldfield of New Zealand, is a classic example of a fault-fracture–hosted epithermal vein system. Gold-silver mineralization was mined in two areas: the open-pit stock-work veins...

... protolith. In this paper we use a variation on MacLean’s (1990) approach to assess mass changes in altered volcanic rocks that host gold mineralization in New Zealand. Epithermal Au-Ag deposits in the Hauraki goldfield, New Zealand, are predominantly hosted in calc-alkaline andesite and dacite...

... than gold and the ratio is about 10 for in situ ore. The most comprehensive early descriptions of the geology of the Waihi field are by Bell and Fraser (1912) and Morgan (1924) . Recent exploration and mining have provided new data and sample material for geological and geochemical studies...

..., with further work, the pXRF could be independently used to infer adularia alteration in the Waihi setting. There are c. 50 epithermal gold-silver deposits in the Hauraki Goldfield of the Coromandel Peninsula ( Fig. 1 ) ( Hollinger & Mauk 2002 ). Waihi Au-Ag mine annually produces 700 000 ounces...

... to regions such as the Hauraki Goldfield, Coromandel Volcanic Zone with only 17 epithermal gold occurrences identified in the region ( Fig. 1 ). These 17 occurrences have been used as training data for this study. Training data are used to calculate the weights for each binary or categorical map to be used...

... the focus of ore deposition at porphyry copper deposits in Chile, and a process-oriented mineral systems approach for metallogeny related to magmatic-hydrothermal Cu and Au deposits. Epigenetic gold systems—models for gold exploration in the northern Cordillera of North America, source of ore fluids...

... ). The Golden Cross deposit is one of over 50 separate low-sulfidation epithermal gold-silver deposits in the Hauraki goldfield ( Christie and Brathwaite, 1986 ). From 1862 to 1952 the Hauraki goldfield produced 44 million ounces (1.4 million kg) of Au-Ag bullion (Au/Ag ratio of 1/4), with 98 percent...