Paul A. Mueller, Joseph L. Wooden; Evidence for Archean subduction and crustal recycling, Wyoming province. Geology ; 16 (10): 871–874. doi: https://doi.org/10.1130/0091-7613(1988)016<0871:EFASAC>2.3.CO;2
Download citation file:
The Beartooth Mountains of the northern Wyoming province contain a suite of incompatible-element-enriched amphibolites of andesitic composition that contains both calcalkalic and tholeitic varieties. These amphibolites formed about 2800 Ma and show trace-element and lead isotopic signatures that suggest an origin similar to some modern andesites produced in convergent margin environments. In particular, these rocks show depletions of the high-field-strength elements (e.g., Nb, Ti, Zr) and enriched Pb isotopic compositions indicative of recycling of Pb from a crustal reservoir into the mantle. These data and other geologic considerations suggest that the northern Wyoming province may have been the site of a Late Archean convergent continental margin.