9. The geology and structure of the zinc deposits

General comments

Both the Franklin and the Sterling Hill orebodies are enclosed in the Precambrian Franklin Marble formation. Sterling Hill is near the center of the Franklin Marble band, which is approximately a half-mile (~800 meters) wide locally, but the Franklin deposit is closer to the formation’s west side, where it has proximity relations to the Furnace Magnetite Bed, the Cork Hill Gneiss, and the overlying Hardyston Quartzite and Kittatinny Limestone (Figure 8-1 and 8-3).




	Figure 8-1. Geologic sketch map of the Franklin-Sterling Hill area, adopted from Pinger (1950). N-arrow is true north.		Figure 8-3. Geologic map of the area adjacent to the Franklin (1) and Sterling Hill (2) orebodies, which are shown as heavy-ruled, black, numbered, hook-shaped symbols in the lower half of the map. The thin gray line passing through the Sterling Hill orebody is the 41^o05’ 00” north latitude line; that passing through the lower part of Franklin Pond is 74^o35’ 00” west longitude and is true north. Map taken from Hague et al. (1956).

The floor of the Wallkill Valley between the deposits is barren of ore; it was the subject of much diligent and intensive exploratory drilling by the New Jersey Zinc Company and studies by outside consultants, such as C. H. Stockwell. The best study of the Franklin deposit is that of Frondel and Baum (1974); there is no document of a similarly comprehensive scope for the Sterling Hill deposit. The ore deposits have not been studied in situ by the writer. The literature uses the terms “vein” and “limb” interchangeably for the long, linear, surface-exposed features of the orebodies.




Copyright © 1995 by Pete J. Dunn			Website by Herb Yeates

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