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A sulfur isotope study of pyrite genesis: The Mid-Proterozoic Newland Formation, Belt Supergroup, Montana

Journal Article · · Geochimica et Cosmochimica Acta; (USA)
 [1];  [2]
  1. Institut fur Geologie, Bochum (Germany, F.R.)
  2. Univ. of Texas, Arlington (USA)
Different generations of sedimentary pyrite from the Mid-Proterozoic Newland Formation, USA, have been analysed for their sulfur isotopic compositions. The results indicate bacterial sulfate reduction as the pyrite forming process. The {delta}{sup 34}S values for early diagenetic pyrite, around -14{per thousand}, are in contrast to dominantly more positive values for many other Middle Proterozoic units. A progressive reduction of sulfate availability during diagenesis can be recognized by an increase in {sup 34}S content (Rayleigh Distillation) as well as through detailed petrographic observations. Contemporaneous seawater had a sulfur isotopic ratio between +14 and +18% as measured from sedimentary barite within the unit.
OSTI ID:
6702093
Journal Information:
Geochimica et Cosmochimica Acta; (USA), Journal Name: Geochimica et Cosmochimica Acta; (USA) Vol. 54:1; ISSN GCACA; ISSN 0016-7037
Country of Publication:
United States
Language:
English