Unnamed Occurrence (ARDF - NB035; west of Monte Cristo Creek), Chisana Mining District, Valdez-Cordova Census Area, Alaska, USAi

Regional Level Types
Unnamed Occurrence (ARDF - NB035; west of Monte Cristo Creek)	- not defined -
Chisana Mining District	Mining District
Valdez-Cordova Census Area	Census Area
Alaska	State
USA	Country

The prospect is in the Wrangell-St. Elias National Preserve.
Location: This occurrence is at an elevation of about 4,900 feet on the north valley-wall of Monte Cristo Creek valley near the point that the creek crosses the east boundary of the Nabesna A-5 quadrangle. The site coincides with one shown on an unpublished National Park Service map; it is near the center of the SW1/4 of section 9, T. 5 N., R. 13 E. of the Copper River Meridian. This is National Park Service locality WRST-19 (unpublished data) and the coordinates for this occurrence were provided by the National Park Service.
Geology: An unpublished National Park Service map and accompanying database identify this locality as a porphyry gold prospect. Bedrock in this part of Monte Cristo Creek is marine and subaerial volcanic and volcaniclastic rocks of the Lower Cretaceous, Chisana Formation (Richter, 1976). Nearly horizontal volcanic rocks of the upper Tertiary and Quaternary, Wrangell Lava unconformably overly the Chisana Formation. The Chisana Formation is extensively hydrothermally altered and is characteristically replaced by gypsum-quartz-sulfide assemblages (Richter, 1976). Tertiary hornblende-plagioclase porphyry crops out downstream in Monte Cristo Creek in the Nabesna A-4 quadrangle. A K/Ar age for this porphyry is 17 Ma (Richter, 1973).
Age: Tertiary? Hydrothermal alteration may be related to the emplacement of a hornblende-plagioclase porphyry downstream in the Nabesna A-4 quadrangle; the porphyry has a 17 Ma K/Ar age (Richter, 1973).
Alteration: Gypsum-quartz-sulfide (pyrite?) replacement of Chisana Formation volcanic rocks. Oxidation is shown by abundant iron-oxide staining.

Commodities (Major) - Au
Development Status: None
Deposit Model: Porphyry gold?

Other Databases

Link to USGS - Alaska:	NB035

Other Regions, Features and Areas containing this locality

References