FINAL TECHNICAL REPORT Detrital Zircon Analysis of Mesoproterozoic and Neoproterozoic High- Grade Metasedimentary Rocks of North-Central Idaho: Reduction of the Mapped Extent of the Belt Basin U.S. Geological Survey Mineral Resources External Research Program Award Number: 04HQGR0153 Principal Investigator: Reed S Lewis Idaho Geological Survey, University of Idaho, Moscow, Idaho 83844, U.S.A. "Research supported by the U.S. Geological Survey (USGS), Department of the Interior, under USGS award number 04HQGR0153. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government." Detrital zircon analysis of Mesoproterozoic and Neoproterozoic high-grade metasedimentary rocks of north-central Idaho: reduction of the mapped extent of the Belt basin Reed S. Lewis, Idaho Geological Survey, University of Idaho, Moscow, Idaho 83844, U.S.A. (
[email protected]; 208-885-7472; FAX: 208-885-5826) Jeff D. Vervoort, Department of Geology, Washington State University, Pullman, Washington 99164, U.S.A. (
[email protected]; 509-335-5597) Russell F. Burmester, Geology Department, Western Washington University, Bellingham, Washington 98225-9080, U.S.A. (
[email protected]; 360-650-3654) Peter Oswald, Department of Geological Sciences, University of Idaho, Moscow, Idaho 83844, U.S.A. (
[email protected]) ABSTRACT We analyzed detrital zircons in 10 amphibolite facies metasedimentary rock samples from north-central Idaho to test the previous assignment of these rocks to the Mesoproterozoic Belt-Purcell Supergroup and to determine whether some may be pre-Belt basement rocks. In addition, zircons from 2 samples of the Prichard Formation (lower Belt), and one sample of Cambrian quartzite were also analyzed.