|Quadrangle map, 1:250,000-scale||YA|
|Quadrangle map, 1:63,360-scale||B-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Situk beach extends southeasterly from the mouth of Lost River to the village of Situk, an approximate distance of 2.4 miles. The coordinates are the approximate mid-point of the beach deposit. The beach is southeast of the Yakutat beach (YA002) and northwest of the Blacksand beach (YA008). This beach placer was included with the Blacksand beach placer by Cobb (1972) as number 6.|
The beach placer is developed on unconsolidated marine and terrestrial deposits of Holocene age and mainly consists of medium coarse sands with pebbly and rocky layers (Reimnitz and Plafker, 1976). When sampled by Foley and others (1995), there were transient layers as much as 0.3 meters thick that were rich in heavy minerals.Samples collected by Thomas and Berryhill (1962) and Foley and others (1995) locally contained abundant heavy metals. Titanium was found to almost 54 pounds/cubic yard; iron to about 150 pounds/cubic yard. Gold was found by Foley and others (1995, Appendix A) in several samples.
|Geologic map unit||(-139.581686980347, 59.4396997098995)|
|Mineral deposit model||Beach placer: single-cycle product of high-energy environment.|
|Age of mineralization||Holocene. Probably mainly derived from reworking of low-grade glacio-fluviatile deposits of Pleistocene and Holocene age.|
|Workings or exploration||
The Situk beach was explored by auger holes and grab samples of heavy concentrate layers in the modern beach. An auger hole reported by Thomas and Berryhill (1962, sample number 25) contained 0.5 ppm gold, 53.9 pounds/cubic yard titanium and 150.3 pounds/cubic yard iron. Three samples, localities 266, 267, and 268, were collected by Foley and others (1995, figure 16, Appendix A). A sample of a modern heavy mineral concentrate layer (no. 267 - 0.3 meters) contained 1.298 grams/ton gold in head split along with 4.05 percent titanium and 2534 ppm zirconium. A spiral concentrate of the same sample contained 0.113 grams/ton gold, 4.86 percent titanium, and 3032 ppm zirconium. Four samples (series no. 266 of a total of 5.5 meters) were collected from the tidal beach; five samples (series no 267 of 9.4 meters) were taken of back beach material near a lagoon. Spiral concentrates of tidal flat samples contained up to 4.72 percent titanium and 0.198 grams/ton gold in the same interval. Back beach samples contained as much as 3.34 percent titanium and a trace of gold over 1.8 meters. One other head sample of the back beach had a trace of gold. There are no workings, but the beach is accessible from the village of Yakutat.The area was also sampled by MacKevett and Plafker (1970).
|Indication of production||Yes; small|
|Production notes||Probably some gold has been produced.|
Additional commentsHistoric mining activity; generally low-grade, but high-grade transient beach deposits exist.
Cobb, E.H., 1972, Metallic mineral resources map of the Yakutat quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-408, 1 sheet, scale 1:250,000.
Foley, J.Y., La Berge, R.D., Grosz, A.E., Oliver, F.S., and Hirt, W.C., 1995, Onshore titanium and related heavy-mineral investigations in the eastern Gulf of Alaska region, southern Alaska: U.S. Bureau of Mines Open-File Report 10-95, 125 p.
MacKevett, E.M., Jr., and Plafker, G., 1970, Geochemical and geophysical reconnaissance of parts of the Yakutat and Mount St. Elias quadrangles, Alaska: U.S. Geological Survey Bulletin 1312-L, p. L1-L12 p.
Reimnitz, Erk, and Plafker, George, 1976, Marine gold placers along the Gulf of Alaska margin: U.S. Geological Survey Bulletin 1415, 16 p., 1 plate.
|Reporters||C. C. Hawley (Hawley Resource Group)|
|Last report date||4/15/1999|