A Special Issue Devoted to Barite and Zn-Pb-Ag Deposits in the Red DOG District, Western Brooks Range, Northern Alaska

摘要

The Brooks Range in northern Alaska (Fig. 1) contains an enormous accumulation of zinc and barite. The four deposits at Red Dog (Qanaiyaq, Main, Aqqaluk, and Paalaaq) have reserves and resources totaling 140.6 Mt at 16.6 percent Zn and 4.6 percent Pb (Jennings and King, 2002), which surpass most deposits worldwide in terms of grade and size (Fig. 2). Including resources of the unmined Su-Lik (38 Mt at 9 percent Zn + Pb; Jennings and King, 2002) and Anarraaq deposits (18 Mt at 23 percent Zn + Pb; King et al., 2002) northwest of Red Dog, the district has about 40 Mt of contained Zn + Pb (Fig, 2), For comparison, both the Broken Hill deposit and the Mt. Isa district (including the George Fisher, Hilton, and Mt. Isa deposits) in Australia contain more than 50 Mt Zn + Pb (Large et al., 2002), The Australian deposits are lead rich compared with the Brooks Range deposits. In terms of total zinc content, the combined deposits of the Red Dog district (approx 31 Mt) rival that of the Mt. Isa district (approx 36 Mt) and surpass Broken Hill (approx 25 Mt). In terms of zinc concentrate production, the Red Dog mine has the worlds largest-almost 600,000 tonnes (t) per year. The Brooks Range barite deposits are extraordinarily large. The barite body at the Anarraaq deposit alone is estimated to be as much as 1 billion metric tonnes (King et al., 2002). The Wulik, Moil, and Gull barite deposits (Fig. 1) are interpreted to be the lateral equivalents of the Anarraaq barite body (J. Clark, Teck Cominco, pers. commun., 2003), making the total area underlain by these deposits a minimum of 20 km~2. Owing to a lack of published information, it is uncertain how this deposit compares with the giant barite bodies in south China, but it dwarfs the estimated amount of barite contained in the entire Nevada barite belt (Johnson et al., 2004, and references therein),