|Quadrangle map, 1:250,000-scale||MH|
|Quadrangle map, 1:63,360-scale||B-1|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The PG East occurrence is approximately 0.4 mile west of peak 7523 at an elevation of about 6,400 feet. It is about one-third mile west of the center of section 18, T. 18 N., R. 6 E., Copper River Meridian. The location is accurate.|
The PG East massive sulfide occurrence is a low-grade sulfide layer or unit within the Tushtena Pass unit. With the PG Southeast prospect (MH263), PG East is part of a 2-mile-long zone of intermittently exposed semimassive and massive sulfides. The sulfides are predominantly pyrite and pyrrhotite with minor chalcopyrite. Massive sulfides reach 2 feet in thickness, and semimassive sulfides are as much as 25 feet thick. Base metal grades are very low. Copper is generally below 0.1 percent, lead, zinc, and silver values do not exceed background, and gold values are about 30 parts per billion (E. Hunter, unpublished data, 1998).The Tushtena Pass unit that hosts the PG East occurrence consists of medium- to coarse-grained, calcareous, quartz-sericite-chlorite-schist with local carbonate interbeds. The unit is is typically green to gray, foliated, schistose to blocky, laminated to medium-bedded, quartz-eye bearing, quartz-rich rocks with subordinate muscovite, sericite, and chlorite. In many places, sheared zones are the loci of pervasive iron-carbonate alteration that weathers to a distinct reddish hue. Discontinuous bands of siliceous limestone, dolomite, marble, and black, weakly pyritic metasiltstones are common (Dashevsky and others, 2003).
|Geologic map unit||(-144.348251395809, 63.3397241491777)|
|Mineral deposit model||Kuroko massive sulfide (Cox and Singer, 1986; model 28a).|
|Mineral deposit model number||28a|
|Age of mineralization||The Drum unit, which is part of the metamorphic sequence that includes the rocks at this deposit, has been dated at the Devonian-Mississippian boundary on the basis of one SHRIMP U-Pb zircon age of 359 +/- 6 Ma at the nearby DD South prospect (MH325) (Dashevsky and others, 2003).|
|Workings or exploration||Only preliminary surface examination of this sulfide occurrence; there are no significantly elevated base or precious metals reported with the iron sulfides (E. Hunter, unpublished data, 1998).|
|Indication of production||None|
Additional commentsUnpublished data cited is available for viewing by contacting Grayd Resources Inc. in Vancouver, B. C., Canada (www.grayd.com), or Northern Associates Inc. in Fairbanks, Alaska.
|Reporters||W.T. Ellis (Alaska Earth Sciences) and A.W. Wyatt and S.S. Dashevsky (Northern Associates Inc.)|
|Last report date||3/20/2003|