Canadian Mineralogist Vol. 14, p.577 (1976) NATIVE LEAD AT KENO HILL, YUKON R. W. BOYLE Geological Survey of Canada, Ottawa KIA 0E8 Recent investigations of the heavy-mineral processg6all amounts of lead are mobile as the concentrates from the oxidized zones of the sulfate, carbonate, and probably also as organic lead-zinc-silver deposits, their overlying soils, (humic) compounds. Disintegration of the humic and the stream sedimentsof the Keno Hill area, ligands in the last type of compounds as a re- Yukon (Gleeson& Boyle in press)have revealed sult of oxidation processes would precipitate the occasional occurrence of native lead. The native lead. Reduction of the sulfate and car- mineral occurs as small ((50 microns) irre- bonate, perhaps by reaction with organic com- gularly rounded massesand thin plates; rarely pounds, may also have produced the native as microscopic dendrites and poorly formed lead, although this mechanism seemsless likely crystals. The most intimate associatein some, than the oxidation of humic compounds. but not all, occurrences is litharge which may It is interesting that four native elements occur as a thin coating on the lead. Other as- have now been identified in the lodes and their sociates are cerussite, massicot(?), wad, and oxidation products at Keno Hill, including na- limonite. Spectrographic analyses of the native tive silver, native gold, native zinc (Boyle 1961), lead indicate the presence of strong traces to and native lead. minor amounts of arsenic and tin and traces of A specimen has been filed in the systematic Ag,Ba,Bi,Co,Cu,Ni, and Sb. reference series of the National Mineral Col- The source of the native lead is undoubtedly leqtion at the Geological Survey of Canada the lead-zinc-silver lodes in which lead as the (No. 12115). element occurs mainly in the hypogene minerals galena, boulangerite, jamesonite, meneghinite, and bournonite @oyle 1965). The principal su- REFERENCES pergene lead minerals are cerussite, anglesite, BenrncveN, P. M. (1966): Native lead and zinc in beudandtite, bindheimite, and plumbojarosite. the rocks of. Armenia Zap. Vses. Mineral. Native lead has not vet-the been observedunder the Obshchest. 95, 99-102. microsodie among hypogene products of BoyLE, R. W. (1961): Native zinc at Keno Hill. mineralization. Can. Mineral. 6, 692-694. According to Palache et al. (l9M) and (1965): Geology, geochemistry, and ori- Chukhrov (1960) native lead is extremely rare, gin of the lead-anc-silver deposits of the Keno Hill area, Yukon Territory. Geol. but tle mineral is'relatively widespread in both Hill-Galena Surv. Can, Bull. LLL. hypogene and supergene environments. The Crrunnov, F. V. (Principal ed.) (1960)z Minerals, native metal is sqmmonly noted in plaier a Guide Book L, Izd. Akad. Nauk S.S.S.R., Mos- (eluvial) concentrates (Bartikyan 1966). cow, 45-4'7. The origin of the native lead at Keno Hill is Gr-ensoN, C. F. & Bovr.g R. W. Cn Press): Minor uncertain. The mineral may be one of the minor and trace element distribution in tle heavy min- products of the hypogene minepll24i6n from erals of the rivers and streams of the Keno Hill which it finds its way ultimately into the oxi- area, Yukon Territory. Geol. Surv. Can. Pap. FnorrroBr,, C. (1944): dized zones, soils, and sheam sediments as a PALAcHE, C., BrnrvuN, H. & The System of Mineralogy 1. John Wiley & Sons, resistate mineral. Alternativeln tle mineral may New York be a reduction product of the oxidation pro- cessesof the lead-zinc-silver lodes. During this Received July 1976. 577 Downloaded from http://pubs.geoscienceworld.org/canmin/article-pdf/14/4/577/3445887/577.pdf by guest on 01 October 2021.