Ore deposits of the Coeur d'Alene district, Shoshone County, Idaho

Abstract

The Coeur d'Alene district of this report is that area in northern Idaho between the Montana State line and longitude 116°17', and between latitudes 47°26'15" and 47°33'45".The country rock of the area consists of the Prichard, Burke, Revett, St. Regis, Wallace, and Striped Peak Formations of the Precambrian Belt Series. These formations are composed of fine-grained quartz-rich rocks that have been mildly regionally metamorphosed and which, in conse• quence now belong to the green schist facies. The ubiquitous sericite was oriented during the folding and metamorphism and the rocks now consist of quartzose slate, sericite phyllite, sericite quartzite, and in a few areas, schistose quartzite and sericite schist.Igneous rocks of the area include monzonite stocks and related monzonite dikes, which were probably intruded at the same time as the Idaho batholith, and biotite lamprophyre, diabase, and porphyritic hornblende-augite-olivine-dikes, the latter perhaps varieties of the diabase dikes. The two stocks are part of a line of northeastward-striking intrusives that apparently lie along a major fracture. This fracture is probably one of the controlling factors in the origin of the Coeur d'Alene district.Several sets of faults can be recognized; there is no certainty that any are older than the shear zones that contain ore deposits, but the great strike-slip faults-the Osburn and Placer Creek faults-have offset mineral belts.Idaho, within which the Coeur d'Alene district is the only important mining area, has ranked second in lead and in zinc production for many years. The first recorded production from the Coeur d'Alene district proper was

Assessing the Influence of Reacting Pyrite and Carbonate Minerals on the Geochemistry of Drainage in the Coeur d'Alene Mining District

“…The carbonate minerals of importance in the CdA mining district are calcite, ankerite, and siderite. Several analyses of the composition of these minerals for the district have been done ( , ) and are summarized in Table . It is clear that the phases are not pure and analyses are limited to only a few locations in the district.…”

“…Total production records indicate that this district ranks as one of the world's largest producers of Ag and one of the United States' major producers of Pb and Zn. Ore deposits are steeply dipping Pb−Zn−Ag veins occurring in Precambrian rocks of the Belt Supergroup ( − ). These host rocks are primarily quartzite and argillite with lesser amounts of interbedded carbonate and carbonate bearing rocks.…”

Modeling Precipitation and Sorption of Elements during Mixing of River Water and Porewater in the Coeur d'Alene River Basin

“…The South Fork of the Coeur d'Alene River and its major tributaries pass through the world class Coeur d'Alene mining district () (see Figure ). Ore deposits are steeply dipping quartz (SiO 2 ) and siderite (FeCO 3 ) veins containing stratigraphically controlled Pb−Zn−Ag ore shoots in Precambrian rocks of the Belt Supergroup ( − ). Veins are separated into two major types by ore mineralogy: (1) lead- and zinc-rich veins having argentiferous galena (PbS) and sphalerite (ZnS) and (2) silver-rich veins having argentiferous tetrahedrite ([(Cu, Ag) 10 (Fe, Zn) 2 Sb 4 S 13 ]) and minor galena and sphalerite.…”

Trends in concentration, loads, and sources of trace metals and nutrients in the Spokane River Watershed, northern Idaho, water years 1990–2018

“…Mineralization in the district occurs in veins hosted in metasedimentary rocks of the Proterozoic Belt Supergroup, with galena, sphalerite, and tetrahedrite being among the most important ore-bearing minerals. Ore deposits occur in a strongly folded and faulted shear zone and are offset by two major strike-slip faults-the Osburn and Placer Creek faults (Fryklund and Weis, 1964).…”