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Stratiform zinc-lead mineralization in Nasina assemblage rocks of the Yukon-Tanana Upland in east-central Alaska

Open-File Report 98-340

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Abstract

The Yukon-Tanana Upland of east-central Alaska and Yukon comprises thrust sheets of ductilely deformed metasedimentary and metaigneous rocks of uncertain age and origin that are overlain by klippen of weakly metamorphosed oceanic rocks of the Seventymile-Slide Mountain terrane, and intruded by post-kinematic Early Jurassic, Cretaceous and Tertiary granitoids. Metamorphosed continental margin strata in the Yukon-Tanana Upland of east-central Alaska are thought to be correlative, on the basis of stratigraphic similarities and sparse Mississippian U-Pb zircon and fossil ages (Mortensen, 1992), with middle Paleozoic metasedimentary and metavolcanic rocks in the eastern Alaska Range and in western and southeastern Yukon. Furthermore, rocks in the northern Yukon-Tanana Upland may correlate across the Tintina fault with unmetamorphosed counterparts in the Selwyn Basin (Murphy and Abbott, 1995). Volcanic-hosted (VMS) and sedimentary exhalative (sedex) massive sulfide occurrences are widely reported for these other areas (green-colored unit of fig. 1) but, as yet, have not been documented in the Alaskan part of the Yukon-Tanana Upland. Recent discoveries of VMS deposits in Devono-Mississippian metavolcanic rocks in the Finlayson Lake area of southeastern Yukon (Hunt, 1997) have increased the potential for finding VMS deposits in rocks of similar lithology and age in the Yukon-Tanana Upland of Alaska. Restoration of 450 km of early Tertiary dextral movement along the Tintina fault juxtaposes these two areas.

Geospatial Extents

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Stratiform zinc-lead mineralization in Nasina assemblage rocks of the Yukon-Tanana Upland in east-central Alaska
Series title:
Open-File Report
Series number:
98-340
Year Published:
1998
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
Geology, Minerals, Energy and Geophysics Science Center
Description:
Report: 26 p.; HTML document
Number of Pages:
26
Country:
United States
State:
Alaska
Other Geospatial:
Yukon-tanana Upland
Online Only (Y/N):
Y