Circular 1319
The foothills of the Brooks Range contain an enormous accumulation of zinc (Zn) in the form of zinc sulfide and barium (Ba) in the form of barite in Carboniferous shale, chert, and mudstone. Most of the resources and reserves of Zn occur in the Red Dog deposit and others in the Red Dog district; these resources and reserves surpass those of most deposits worldwide in terms of size and grade. In addition to zinc and lead sulfides (which contain silver, Ag) and barite, correlative strata host phosphate deposits. Furthermore, prolific hydrocarbon source rocks of Carboniferous and Triassic to Early Jurassic age generated considerable amounts of petroleum that may have contributed to the world-class petroleum resources of the North Slope. Deposits of Zn-Pb-Ag or barite as large as those in the Brooks Range are very rare on a global basis and, accordingly, multiple coincident favorable factors must be invoked to explain their origins. To improve our understanding of these factors and to contribute to more effective assessments of resources in sedimentary basins of northern Alaska and throughout the world, the Mineral Resources Program and the Energy Resources Program of the U.S. Geological Survey (USGS) initiated a project that was aimed at understanding the petroleum maturation and mineralization history of parts of the Brooks Range that were previously poorly characterized. The project, titled “Regional Fluid Flow and Basin Modeling in Northern Alaska,” was undertaken in collaboration with industry, academia, and other government agencies. This Circular contains papers that describe the results of the recently completed project. The studies that are highlighted in these papers have led to a better understanding of the following:
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Version 1.0 Posted January 2008 |
Kelley, K.D., ed., 2008, Regional fluid flow and basin modeling in northern Alaska: U.S. Geological Survey Circular 1319, 45 p.
1. Introduction
2. Depositional Settings and Age of Carboniferous Rocks in the Western Brooks Range, Alaska
3. Geochemistry of Paleozoic Sedimentary Rocks: Metallogenic Significance
4. Depositional Models for Barite and Zinc
5. Insights into the Ore-Forming Fluids
6. Geochemical Indicators of Massive Sulfide Deposits and Vein Breccia Zn-Pb-Ag Occurrences
7. Sulfur and Oxygen Isotope Chemistry of Barite
8. Radiogenic Isotope Studies
9. Phosphatic Rocks of the Lisburne Group
10. Metalliferous Tasmanite and Oil Shale
11. Preliminary Retrodeformable Regional Cross Section, Western Brooks Range
12. Geologic Rationale for Extensional Basin Framework During Red Dog Mineralization
13. Lisburne Petroleum System
References
Glossary of Terms