Geologic description
The rocks in the area consist of Upper Devonian to Lower Mississippian, Kayayut Conglomerate and Kayak Shale(?). The mineralization is mostly in massive to crossbedded sandstone of the Kanayut Conglomerate but some is in red-brown, carbonate-cemented, interbedded sandstone, siltstone, coal, and shale that may be part of the Kayak Shale, or a lateral equivalent (Kurtak and others, 1995). The mineralization is along a probable, southeast-dipping, low angle thrust-faulted zone at the base of Kivliktort Mountain (Kurtak and others, 1995). The structure in the area is complex and there are numerous repeated sections of the Kayayut Conglomerate and Kayak Shale. There are four types of mineralization: breccia, vein, replacement, and disseminated. The mineralization is accompanied by silicification and bleaching of the sandstone. Abundant mineralized float with galena and sphalerite extends over a northeast-trending area about 20 meters by 100 meters in size. Breccia along the thrust faults is cemented by quartz, sphalerite, and galena. Disseminated sphalerite occurs in sandstone near the thrust faults and sphalerite replaces coal. Sphalerite veins and late barite veins occur locally. Selected samples contained up to 31.5 percent zinc, 2.8 percent lead, and 26.1 grams of silver per tonne. There is considerable evidence for remobilization of the sulfides from what may have originally been a sandstone-type lead-zinc deposit. Lead isotope values from galena are: Pb 206/204 = 18.632; Pb 207/204 = 15.617, and Pb 208/204 = 38.353. These data suggest a Mississippian to Pennsylvanian model age and remobilization of the sulfides. |
