Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Young, G. M. Search for Related Content GeoRef GeoRef Citation

Geochemical investigation of a Neoproterozoic glacial unit: The Mineral Fork Formation in the Wasatch Range, Utah

¹ Department of Earth Sciences, University of Western Ontario, London, Ontario N6A 5B7, Canada

The Mineral Fork Formation is an isolated unit of Neoproterozoic glaciogenic rocks in the Wasatch Range in northwestern Utah. Geochemical analyses of diamictite and mudstone samples were carried out to document its major and trace element geochemistry. Comparison of the lower and upper parts of the formation, which have been ascribed to different tectonic and sedimentological settings, revealed no striking differences, but the analyzed samples show a gradual upward increase in CaO, MgO, Fe₂O₃, MnO, and P₂O₅ and a decrease in SiO₂. TiO₂:Al₂O₃ ratios that suggest a provenance throughout the formation with an average composition slightly more mafic than average upper crust. The mudstones are more K rich than the diamictites. Calculation of a chemical index of alteration (CIA) is complicated by the presence of carbonate minerals. After making corrections for carbonate content, CIA values range from 65 to 70. These values are higher than those from Paleoproterozoic glaciogenic deposits. Some mudstones in the upper part of the formation are Fe rich (15% Fe₂O₃), approaching the composition of iron formations. The ferruginous nature supports previous correlation with Fe-rich glaciogenic rocks of the Rapitan Group in the northern Canadian Cordillera. Trace elements, including rare earth elements, suggest that the materials in the Mineral Fork Formation were largely derived from a post-Archean source. Most of the widespread glaciogenic rocks of the Neoproterozoic were derived from older sedimentary materials, whereas the deposits of the earlier great glacial episode in the Paleoproterozoic contain a much higher proportion of crystalline materials.

Key Words: diamictite • geochemistry • glaciation • mudstone • Neoproterozoic • provenance

This article has been cited by other articles:

				J. D. Bloch, J. M. Timmons, L. J. Crossey, G. E. Gehrels, and K. E. Karlstrom Mudstone Petrology of the Mesoproterozoic Unkar Group, Grand Canyon, U.S.A.: Provenance, Weathering, and Sediment Transport on Intracratonic Rodinia Journal of Sedimentary Research, September 1, 2006; 76(9): 1106 - 1119. [Abstract] [Full Text] [PDF]

				T. W. Ruks, S. J. Piercey, J. J. Ryan, M. E. Villeneuve, and R. A. Creaser Mid- to late Paleozoic K-feldspar augen granitoids of the Yukon-Tanana terrane, Yukon, Canada: Implications for crustal growth and tectonic evolution of the northern Cordillera Geological Society of America Bulletin, September 1, 2006; 118(9-10): 1212 - 1231. [Abstract] [Full Text] [PDF]

				L.R. JONES, B. LAFRANCE, and C.J. BEAUMONT-SMITH Structural Controls on Gold Mineralization at the Burnt Timber Mine, Lynn Lake Greenstone Belt, Trans-Hudson Orogen, Manitoba Exploration and Mining Geology, January 1, 2006; 15(1-2): 89 - 100. [Abstract] [Full Text] [PDF]

				S. J. Piercey, D. C. Murphy, J. K. Mortensen, and R. A. Creaser Mid-Paleozoic initiation of the northern Cordilleran marginal backarc basin: Geologic, geochemical, and neodymium isotope evidence from the oldest mafic magmatic rocks in the Yukon-Tanana terrane, Finlayson Lake district, southeast Yukon, Canada Geological Society of America Bulletin, September 1, 2004; 116(9-10): 1087 - 1106. [Abstract] [Full Text] [PDF]