|Quadrangle map, 1:250,000-scale||LC|
|Quadrangle map, 1:63,360-scale||C-7|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Occurrence (mine ?) is at the confluence of the Chilikadrotna River with the Mulchatna River. Sec. 22, T. 6 N., R. 35 W., of the Seward Meridian. Accurate within 1.6 km.|
Geologic descriptionLambert's Bar is a placer gold occurrence (mine ?) on the Mulchatna River. The most abundant bedrock in the areas upstream of the locality is unit KJs. Nelson and others (1983) described unit KJs as interbedded lithic graywacke, silty sandstone, black shale , and local conglomerate. Irregular quartz segregations and veinlets are locally present. Scattered stocks and locally abundant dikes of intermediate to felsic composition intrude these sedimentary rocks. Adjacent to some of the larger igneous bodies are narrow contact aureoles of pelitic hornfels. Unit KJs is intruded (locally) by various Cretaceous to Tertiary plutons. The plutons include a quartz monzonite. One pluton yielded a potassium-argon age on hornblende of 71.3 +/- 2.1 m.y. (Eakins and others, 1978). Also present is Unit Tv of Nelson and others (1983) which includes: rhyolitic breccia, ash-flow tuff, flows, and intrusive rocks and subordinate mafic to intermediate flows. Potassium-argon ages for unit Tv range from 56.2 to 62.7 m.y. indicating a Tertiary age for these rocks (Eakins and others, 1978).
|Geologic map unit||(-155.392246478131, 60.589313523731)|
|Mineral deposit model||Placer Au (Cox and Singer, 1986; model 39a)|
|Mineral deposit model number||39a|
|Age of mineralization||The placer gold is Quaternary, the source of gold could come from a variety of rocks with diverse ages.|
|Alteration of deposit||Not applicable|
|Workings or exploration||Unknown|
|Indication of production||Undetermined|
|Reserve estimates||No reserves|
Additional commentsThis locality appeared on a map in Cobb (1973). The text did not provide any information about the site. Cobb and Reed (1981) mention gold in most river bars of the Mulchatna River, with most prospecting occurring around the late 1890s or early 1900s.
Cobb, E.H., and Reed, B.L., 1981, Summaries of data on and lists of references to metallic and selected nonmetallic mineral occurrences in the Iliamna, Lake Clark, Lime Hills, and McGrath quadrangles, Alaska; Supplement to Open-File Report 76-485; Part A, Summaries to January 1, 1981: U.S. Geological Survey Open-File Report 81-1343-A, 25 p.
Eakins, G.R., Gilbert W.G., and Buntzen, T.K., 1978, Preliminary bedrock geology and mineral resource potential of west-central Lake Clark quadrangle, Alaska: Alaska Division of Geological and Geophysical Surveys Open-File Report 118, 15 p., 2 plates, scale 1:25,000.
|Reporters||D.P. Bickerstaff (USGS)|
|Last report date||6/15/1998|