Low-fluorine Stockwork Molybdenite Deposits
Open-File Report
2009-1211
Links
- More information: USGS Index Page (html)
- Download citation as: RIS | Dublin Core
Abstract
Low-fluorine stockwork molybdenite deposits are closely related to porphyry copper deposits, being similar in their tectonic setting (continental volcanic arc) and the petrology (calc-alkaline) of associated igneous rock types. They are mainly restricted to the Cordillera of western Canada and the northwest United States, and their distribution elsewhere in the world may be limited. The deposits consist of stockwork bodies of molybdenite-bearing quartz veinlets that are present in and around the upper parts of intermediate to felsic intrusions. The deposits are relatively low grade (0.05 to 0.2 percent Mo), but relatively large, commonly >50 million tons. The source plutons for these deposits range from granodiorite to granite in composition; the deposits primarily form in continental margin subduction-related magmatic arcs, often concurrent with formation of nearby porphyry copper deposits. Oxidation of pyrite in unmined deposits or in tailings and waste rock during weathering can lead to development of acid-rock drainage and limonite-rich gossans. Waters associated with low-fluorine stockwork molybdenite deposits tend to be nearly neutral in pH; variable in concentrations of molybdenum (<2 to >10,000 ug/L); below regulatory guidelines for copper, iron, lead, zinc, and mercury; and locally may exceed guidelines for arsenic, cadmium, and selenium.
Suggested Citation
Ludington, S., Hammarstrom, J., and Piatak, N.M., 2009, Low-fluorine Stockwork Molybdenite Deposits: U.S. Geological Survey Open-File Report 2009-1211, Available online and on CD-ROM, https://doi.org/10.3133/ofr20091211.
ISSN: 2331-1258 (online)
Study Area
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Low-fluorine Stockwork Molybdenite Deposits |
| Series title | Open-File Report |
| Series number | 2009-1211 |
| DOI | 10.3133/ofr20091211 |
| Year Published | 2009 |
| Language | ENGLISH |
| Publisher | U.S. Geological Survey |
| Contributing office(s) | Eastern Mineral and Environmental Resources Science Center, U.S. Geological Survey |
| Description | Available online and on CD-ROM |