268 Economic Geology

Wednesday, 28 September 2016
8:00 AM - 12:00 PM
Room 301

TRACE ELEMENT ANALYSIS OF PLACER GOLD SAMPLES

Paper number: 268-10
Program: Technical Sessions
Time: 10:15 AM – 10:30 AM

Authors

  • Tiffany D. Luterbach Presenting Author
    New Mexico Institute of Mining and Technology, Socorro, NM
  • Virginia T. McLemore
    New Mexico Bureau of Geology and Mineral Resources, New Mexico Institute of Mining and Technology, Socorro, NM

Abstract

Trace element analysis of placer gold can be used as a valuable exploration tool to determine the original deposit source and locate lode gold deposits. There are a number of elements which can, in various quantities, be present in placer gold particles. Native gold can be in complete solid solution with native silver and contain additional elements including Cu, As, Pb, Fe, and S. There is a reoccurring pattern of silver depletion along the rim of placer gold grains, which is observed in placer particles from New Mexico, Alaska, Arizona, and other deposits, whereas grains located at the original deposit source exhibit no such rim. Placer gold collected from multiple districts in New Mexico and Alaska, coupled with a broad database of previously analyzed placer gold samples indicate correlations between chemical signatures (especially gold, silver, and copper) and type of deposits (i.e., Au-rich copper porphyry deposits, Au porphyry deposits, skarns, and epithermal deposits). By completing a chemical analysis and determining the particle morphology of placer gold collected from these districts using an electron microprobe, patterns in the chemical signatures from each location can be used to examine chemical variability (1) within the individual placer gold particles, (2) within the same district and (3) among different districts.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-287543

© Copyright 2016 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.