| Abstract: | The Balmat-Edwards Zn-Pb district in New York is in Mid-Proterozoic Grenville marbles. Tabular to podiform, generally conformable massive sphalerite-galena orebodies occur at various horizons in the approx 1 km-thick marbles. Metamorphism obscured or obliterated most primary characteristics, whose reconstruction is attempted through detailed S, C, and O isotope studies of the Fowler orebody, and trace element and S isotope studies of sphalerite concentrates and composite ore samples from 22 orebodies. Sulphur isotope data reflect equilibration at near peak metamorphism with some indication of re-equilibration during retrograde metamorphism. The carbon and oxygen isotope composition of gangue carbonates suggests derivation from the host marbles. The oxygen isotope composition of gangue quartz is compatible with a chert origin or metamorphism-equilibration with other minerals. Sulphur and lead isotopes and sulphide mineralogy suggests that the ore fluids were evolved basin brines, chemically like those responsible for Mississippi Valley-type deposits. The large stratigraphic span (> 600 m) of the Balmat orebodies may be due to basin dewatering of million-year intervals. Stratigraphically increasing 34S values of evaporite-anhydrite are postulated to record hydrothermal events and to imply bacterial sulphate reduction on an unusually large scale. Such a stratigraphic increase may be a general exploration guide where sediment-hosted exhalative deposits or Mississippi Valley-type deposits occur.-G.J.N. |
| Genre: | Article |
| ProdID: | 70013145 |
| Citation Author: | Whelan, J. F.; Rye, R. O.; Delorraine, W. |
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| Citation End Page: | 265 |
| Citation Issue: | 2 |
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| Citation Language: | English |
| Citation Larger Work Title: | Economic Geology |
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| Citation Number Of Pages: | 27 |
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| Citation Search Results Text: | The Balmat-Edwards zinc-lead deposits-synsedimentary ore from Mississippi valley-type fluids.; 1984; Article; Journal; Economic Geology; Whelan, J. F.; Rye, R. O.; Delorraine, W. |
| Citation Start Page: | 239 |
| Citation Volume: | 79 |
| Citation Year: | 1984 |
| Type: | citation/reference |
| Text: | The Balmat-Edwards zinc-lead deposits-synsedimentary ore from Mississippi valley-type fluids.; 1984; Article; Journal; Economic Geology; Whelan, J. F.; Rye, R. O.; Delorraine, W. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Sun, 1 Jan 1984 00:00 -0600 |
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