Jorgensen; Mountain Creek; Mary's Gulch Mine, Nome Mining District, Nome Census Area, Alaska, USAi

Regional Level Types
Jorgensen; Mountain Creek; Mary's Gulch Mine	Mine
Nome Mining District	Mining District
Nome Census Area	Census Area
Alaska	State
USA	Country

Location: This site includes lode and placer deposits in the Mountain Creek, Mary Gulch, and Nellie Gulch area. The Jorgensen lode claims appear to underlie part of the Mountain Creek placer deposit at an approximate elevation of 250 feet. The map location is at an elevation of 200 feet in Mary Gulch, in the NW1/4 section 35, T. 10 S., R. 34 W., Kateel River Meridian. This location is probably accurate to within 250 feet. The Mary's Gulch No. 3 placer claim (U.S. Mineral Survey No. 781) appears to be on what is now called Nellie Gulch, about one-half mile farther west and at an elevation of about 50 feet. The Jorgensen lode claims (unpatented) and the Mountain Creek placer (patented, U.S. Mineral Survey No. 710) are essentially the same as locality 8 of Hummel (1962 [MF 243]). The Jorgensen prospect was included in locality 47 of (Cobb, 1972 [MF 463], 1978 [OFR 78-93]).
Geology: The placer gold deposit in Mountain Creek, discovered in September, 1898, by E.O. Lindblom and his associates, was probably the first important placer discovery in the Nome district. A narrow gulch placer deposit on the creek appears to have been mined by 1905, although there may have been more mining after completion of the Miocene Ditch. Mountain Creek follows a steep, west-northwest-striking fault (C.C. Hawley, unpublished data, 1994). The fault cuts chlorite-rich metaturbidite schist and marble (Bundtzen and others, 1994); on the basis of the displacement of a marble layer, the apparent vertical movement on the fault is about 25 feet. At the Jorgensen prospect, Mertie (1918, p. 434-435) described a steep, N 65 W fault, as well as vertical quartz veins and stringers that cut the schist. Arsenopyrite is especially abundant in the schist along the fault. Panning recovered free gold that was fine, even-grained and heavily iron-stained. Joint planes (N 30 E, 70 N) in sulfidized schist along the fault are conspicuously iron-stained. Mertie (1918) believed that the Jorgensen deposit proved that gold was associated with sulfidized schist and had little to do with the introduced quartz. He found scheelite in an iron-stained quartz vein. The same locality was visited in about 1920 by Cathcart (1922, p. 240-241), who reported mine workings in mineralized schist and bleached marble. He identified the gangue feldspar as oligoclase, rather than albite. Pyrite, arsenopyrite, and galena occur in veins cutting quartz. Quartz veins in marble are nearly concordant but locally cut the layering; they contain less galena than veins in the schist. Like Mertie, Cathcart believed that most of the gold was introduced in a later sulfide-rich event. The structural history of the deposit is complex. It could include an early ductile event, followed by a brittle event marked by opening and reopening of the northeast-striking veins and stringers. Ore paragenesis may include (1) semiconcordant weakly auriferous quartz-feldspar-galena veins, (2) faulting, and (3) auriferous sulfidization of schist and introduction of gold in late veinlets.
Workings: These placer and lode deposits have been explored by shallow cuts and trenches. The Mountain Creek placer was located on September 9 and 19, 1898, recorded on October 18, 1898, and amended on October 22, 1900. A narrow, linear placer mine had been developed for at least 2,000 feet below the forks in the uppermost creek by the date of patent survey in November 1905 (U.S. Mineral Survey No. 710). The discovery in Mountain Creek was apparently the first made by E.O. Lindblom and his associates, the so-called Lucky Swedes. They must have been skillful and extremely hard-working prospectors because they also discovered Snow Gulch, Glacier Creek, and Rock Creek before they made their important discovery on Anvil Creek on September 22, 1898. The Miocene Ditch was ultimately extended to give a source of hydraulic water for the Mountain Creek mine. In 1916, Mertie (1918 [B 662-I, p. 425-449]) found prospector A.C. Jorgensen prospecting a lode beneath the previously mined placer. The general area was prospected by Newmont Mining Company in 1992.
Age: Mid-Cretaceous; veins cut schist and marble metamorphosed during the mid-Cretaceous; see NM207.
Alteration: Albitization; bleaching and silicification of marble; and sulfidization of schist.
Production: Gold has been produced from the Mountain Creek placer and from weathered material over the in-situ lode.

Commodities (Major) - Au; (Minor) - Ag, Pb, W
Development Status: Yes
Deposit Model: Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a); partly residual

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Link to USGS - Alaska:	NM229

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References