8. Regional and local geology of the Franklin - Sterling Hill area

General discussion

Among the early geological studies of the region was a particularly good paper by Vanuxem and Keating (1822) and fine studies by Shepard (1832), Rogers (1836, 1840), Kitchell (1856), Cook (1868), and others. These served to set out the general outlines of the local geology, define the major rock types and relations, and provide a stimulus for the work to follow. Here were born the early theories for the formation of the ore deposits, the early orebody descriptions, and an awareness among scientists that this was indeed a truly unique place for geologists to visit and study. Geological studies toward the end of the century by Nason (1889), Kemp (1893a), Wolff and Brooks (1898), and Salisbury (1898) were both intensive and extensive. Those of Nason were in large part concerned with the Franklin Marble (in exhaustive detail) and those of Kemp with the two zinc orebodies; these are discussed below.

Both orebodies are drained by the Wallkill River, known as the Twishsawkin to the Lenni Lenape. Blair and Jenning (1913) and Fletcher (1975) provided much detail on the local soils; these are nice complements to Salisbury’s (1898) study and the fine summary given by Van Hise and Leith (1909). Large-scale, detailed, regional, geological studies really began in earnest with the Franklin Furnace Folio (Spencer et al., 1908) and a summary report (Spencer, 1908). In this folio, for the first time, were set out in grand style the geography, geology, and history of the economic aspects of the area, including the structural, topographic, surficial, glacial, and petrologic aspects of the local geology, together with maps. It also included a section on the local minerals by Charles Palache; the geology section of Palache’s (1935) monograph was drawn largely from the Franklin Furnace Folio. The later, detailed paper by Ries and Bowen (1922) is of particular merit.




	Figure 8-1. Geologic sketch map of the Franklin-Sterling Hill area, adopted from Pinger (1950). N-arrow is true north.

In 1948 Pinger published a very concise paper on the geology of the area. It is particularly valued because Pinger worked here for much of his life and, although a very conservative writer, was the outstanding expert on the deposits. Pinger’s effort was followed by that of Hague et al. (1956) who described a section of the local area 5 miles wide by 30 miles long, trending northeasterly, and including the areas near the zinc deposits; this was followed by a fine and detailed study of the Edison Mine area by Baker (1955). Baker and Buddington (1970) built on the previous studies and made numerous contributions, especially concerning the magnetite deposits, later also studied by Puffer et al. (1992, 1993). Maxey (1971) studied the regional amphibolites, and an aeromagnetic survey was done by Henderson et al. (1957). The paper by Frondel and Baum (1974) provides the best recent geologic summary on the Franklin orebody.

The local topography was illustrated by Pike (1899), Spencer et al. (1908), and Palache (1935), and geologic maps from some of the above-cited papers are shown in figures 8-1, 8-2, 8-3, and 8-4.




	Figure 8-2. Geologic map of part of the Franklin area. Black circles with “Z” overprints indicate the location of the zinc orebodies. Vertical margin is true north and is 2.85 miles (4.5 kilometers) for scale. Map taken from Baker and Buddington (1970).		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).

Full volumes on the geology of New Jersey were published by Lewis and Kümmel (1915) and Wilber and Johnson (1940). Recent geological studies of a more limited scope have been published by Widmer (1964), Vreeland (1966), Lucey (1969), and Herpers (1961). The stratigraphy of some rocks in the northern Reading Prong was provided by Gundersen (1985).




	Figure 8-4. Geologic map of the Franklin mining district; this is the “Special Map.” Illustration from Palache (1935).

The writer has only generally examined the local geology. The geology sections of this text are syntheses drawn entirely from the published record, as noted above, and largely from Hague et al. (1956), Baker and Buddington (1970), Frondel and Baum (1974), and Drake as cited below.

FOOTER LBI




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

Link to homepage
This page created: January 17, 2001