The copper deposits of Moke Creek, West Otago

Abstract

855Two parallel copper-bearing formations are present in the schists of the Moke Creek district, 12 miles north of Queenstown. Most previous observers have reported unfavourably on the value of the deposits, but have given little factual information; few details of past prospecting are now available. The deposits consist of thin laminae of pyrite, pyrrhotite, chalcopyrite, and other sulphides, interlaminated in green schist. They are pre-metamorphic and were probably derived from a submarine volcanic source. Two or three laminae are commonly present and have a total average thickness of about 8 in. On present exposures the quantity of sulphide is estimated at 50,000 tons, and the copper percentage at 10-12 percent. At mining widths the product would have a little over 2 percent copper. These are considered to be conservative estimates, and refer to only one part of the deposits. Other parts undoubtedly contain greater quantities but no estimates can be given. Suggestions are offered for further exploration.

Mineragraphy and origin of copper-bearing sulphides at Waitahuna River, eastern Otago

“…The occurrence of the sulphides in green schists, and the probable volcanic derivation of the latter, suggest a volcanic-sedimentary origin in which fine-grained sulphides were deposited in porous pyroclastics, or precipitated on the sea floor, forming an initially more-or-less bedded syngenetic deposit. A similar origin was suggested for Moke Creek (Wright 1966;Wood 1967).…”

“…Metamorphic grade of country rock Chlorite subzone 3 or Textural Zone 3B at Waitahuna River; chlorite subzone 4 (Hutton 1940;Wood 1962) or Textural Zone 4 (Henley 1975) at Moke Creek.…”

Lithology, geochemistry, and structure of Moke Creek sulphide deposit host rocks, Otago Schist, New Zealand

“…These deposits have been used as indicators of potential base metal mineralisation in the Otago Schist by numerous mineral exploration companies over the past c. 140 yr, although exploration has been unsuccessful thus far. The Moke Creek sulphide deposit itself has been mined on a very limited scale for contained copper, but there is no G01004;published 21 June 2002Received 7 February 2001accepted 9 November 2001 evidence of economic amounts of ore. Wood (1967) estimated that c. 45 000 t of sulphide ore are present. However, comparison of this minor occurrence with other similar, but economic, deposits in similar terranes elsewhere in the world (e.g., Henley 1975) during this study suggests that there is still potential for the discovery of larger deposits in the Otago Schist.…”

“…Numerous earlier workers (Wright 1966;Wood 1967;Henley 1975;Lowery 1979;Jamieson & Craw 1987) have described various aspects of the Moke Creek sulphide deposit itself, focusing on sulphide mineralogy. However, apart from generalised regional studies (Park 1909;Hutton 1940;Mortimer 1993), there is no published information on the host rocks of the Moke Creek sulphide deposit.…”

Metamorphism of the Moke Creek lode, Otago, New Zealand

“…General descriptions and location maps of this small deposit are given by Williams (1965), and Wood (1967), but some further description is pertinent at this time.…”