Earth and Planetary Sciences ETDs

Publication Date

5-2-1972

Abstract

Limestone samples (424) from both surface and subsurface horizons in the New Jersey Zinc mines at Hanover have been analyzed by atomic absorption spectrophotometry for Ag, Cd, Mn, Pb, Zn, Cu and Sn. The lead­zinc ore bodies, occurring in Paleozoic limestones are a typical example of hydrothermal deposits; and are related to the Hanover intrusive. The distribution of trace elements in surface limestones was mainly due to primary dispersion, partly due to secondary dispersion. The depth of ore mineralization, concentration of element in ore solutions, porosity of limestones, diffusion coefficients of element, and the chemical nature of elements in the carbonate and secondary leaching environments were responsible for the concentration of trace elements in the present surface limestones. The anomalous concentrations of elements are located on the northern and southern sides of the mines. The surface anomalies of Pb, Mn, Sn, Cu and Zn (to some extent) are most reliable indicators of lead-zinc deposits below. The lead-zinc ore bodies were concentrated mostly in either the northern or southern half of the mines. The ore solutions were high in Mn and low in Ag, Cd, and Sn. Most of the Cu was deposited as chalcopyrite in early stages, and very little was associated with lead-zinc ores. The ratios between Zn and either Cd, Mn, or Cu suggest three possible types of zinc mineralization. A lateral and vertical zoning of elements (far from a perfect zoning) exists in the area. Distribution of Zn/Pb ratios, Zn/Cd ratios high concentration of Cu in the ores of the southern side of the mines, and high zinc ores away from the Hanover intrusive indicate a second source of mineralization on the southern side of the mines (possibly related to the Santa Rita Stock - south­ eastern part of the mines). The hydrothermal ore solutions from the Hanover intrusive side have deposited ores at shallower depths than the ore solutions from the southern side (away from the Hanover intrusive). Several factors besides the two sources of mineralization are considered to explain the lack of a perfect zoning and the variations in the concentration and distribution of ores and related elements in subsurface limestones. The spread of high and low lead-zinc ores in the subsurface limestones indicates seven main channels of ore solutions. Four of these are located near the Hanover intrusive, and two are located away from the intrusive. The last one, deeper than the others, is located in the central part of the mines. The compositional mixing of ore solutions from these channels at different depths is evidenced in the area. The distribution patterns (isograds) of ores and trace elements (in surface and subsurface limestones) indicate two major fracture systems, one trending northeast and the other northwest.

Degree Name

Earth and Planetary Sciences

Level of Degree

Masters

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

J. Paul Fitzsimmons

Second Committee Member

Abraham Rosenzweig

Third Committee Member

Douglas Gridley Brookins

Language

English

Document Type

Thesis

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