• journal_title：Economic Geology
• Contributor：Robert G. Eppinger ; David L. Fey ; Stuart A. Giles ; Eric C. Grunsky ; Karen D. Kelley ; Burke J. Minsley ; Leeann Munk ; Steven M. Smith
• Publisher：Society of Economic Geologists
• Date：2013-05-01
• Format：text/html
• Language：en
• Identifier：10.2113/econgeo.108.3.495
• journal_abbrev：Economic Geology
• issn：0361-0128
• volume：108
• issue：3
• firstpage：495
• section：Articles

Exploration geochemical and mineralogical studies by the U.S. Geological Survey at the Pebble porphyry Cu-Au-Mo deposit were designed to (1) determine whether the concealed deposit can be detected with surface samples, (2) better understand the processes of metal migration from the deposit to the surface, and (3) test existing methods for assessing concealed mineral resources and/or develop new ones. Surface water (ponds, streams, and springs), pond and stream sediment, soils subjected to various leaching techniques, and glacial till samples were collected. The tilted nature of the undisturbed orebody, varying depth of cover, and later glacial processes, strongly influence the geochemical responses and processes active on the various sample media. The multimedia approach aids in identifying possible processes that caused the significant geochemical variations within and among the various media. These processes include the following: