The Anarraaq prospect was found in 1999 by Teck Cominco by drilling a gravity anomaly (Kelley, Dumoulin, and Jennings, 2004). In plan view the deposit is about 300 by 400 meters in area and consists of a flat-lying lens of massive and banded sulfides up to about 100 meters thick, that is overlain stratigraphically by a thick, continuous layer of barite.

The Anarraag deposit is in shale, mudstone, and carbonate of the Mississippian Ikalukrok unit of the Kuna Formation, which is overlain by the Pennsylvanian to Permian Siksikpuk Formation (Kelley and Jennings, 2004, supplemental map; Kelley, Dumoulin, and Jennings, 2004). The Ikalukrok unit varies greatly in thickness from about 135 to 350 meters.

The sulfide zone at Anarraaq varies in thickness from a few meters to more than 100 meters. There are three types of mineralization: 1) low grade zones (less than 8 percent zinc) with sphalerite, galena, and up to 60 percent pyrite and marcasite; 2) banded sulfides with laminated sphalerite, galena, pyrite, marcasite, and quartz; and 3) massive sphalerite, galena, pyrite, and marcasite in breccias, contorted bands, and veins. The barite layer above the massive and banded sulfides is 65 to 140 meters thick under the entire drilled area and from the top down consists of modular barite, massive banded barite, and calcareous barite. Carbonate replacement by sulfides and barite played a critical role in localizing them.