Other formats

    Adobe Portable Document Format file (facsimile images)   TEI XML file   ePub eBook file  

Connect

    mail icontwitter iconBlogspot iconrss icon

The Pamphlet Collection of Sir Robert Stout: Volume 75

Reefton, Nelson, South Island of New Zealand

page 21

Reefton, Nelson, South Island of New Zealand.

This district, till lately the most productive of gold from quartz-lodes in New Zealand, carries its gold-veins in Carboniferous rocks; the Devonian strata, though well represented in it, not having been found to contain auriferous reefs.

The Reefton quartz-bodies often consist of bunches or irregular masses, branching in all directions into the country-rock. These are aggregated along certain lines, the space between two bunches on such a line being occupied by a connecting-fissure, generally very narrow and often filled with quartz or "pug." (See Fig. 4.)

The bunches of quartz are not continuous to any great extent. The horizontal section of one of them has been compared in form to an octopus. It is noticeable that the lodes pinch to a mere trace or connecting-fissure in the harder parts of the country-rock, while the quartz-bodies are invariably surrounded by rock showing evidences of severe faulting and crushing. Nearly every sample of this softer country-rock analyzed was traversed by slickensides and heads in all directions to such an extent that it was difficult to procure a solid hand-specimen, as the pieces would not stand dressing with the hammer. Samples illustrating the hard rock enclosing the narrow lode-fissures, and the softer, kindly, much-faulted rock bounding the wider auriferous bodies were taken by Mr. T. Esdaile, of the Otago School of Mines, from the deep levels of three of the best-developed mines of the district—the Wealth of Nations, the Progress and the Hercules. The results of analyses are given in Table XV., which shows: (1) that the hard, solid slate contains, as a rule, very little pyrite, and is not auriferous; (2) that the broken country around the bunches of auriferous quartz contains a much larger percentage of pyrite, and that this pyrite, when near the lode, is auriferous; and (3) that although several samples of slate taken 140 to 200 feet from the lode carried large quantities of pyrite, this pyrite contained no gold (see e, g, m, Table XV.).