Title: Regional Middle Proterozoic enrichment of the subcontinental mantle source of igneous rocks from central Montana
Abstract: Research Article| January 01, 1987 Regional Middle Proterozoic enrichment of the subcontinental mantle source of igneous rocks from central Montana Francis Ö. Dudás; Francis Ö. Dudás 1Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802 Search for other works by this author on: GSW Google Scholar Richard W. Carlson; Richard W. Carlson 2Department of Terrestrial Magnetism, Carnegie Institute of Washington, 5241 Broad Branch Road, N.W. Washington, D.C. 20015 Search for other works by this author on: GSW Google Scholar David H. Eggler David H. Eggler 3Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802 Search for other works by this author on: GSW Google Scholar Author and Article Information Francis Ö. Dudás 1Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802 Richard W. Carlson 2Department of Terrestrial Magnetism, Carnegie Institute of Washington, 5241 Broad Branch Road, N.W. Washington, D.C. 20015 David H. Eggler 3Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1987) 15 (1): 22–25. https://doi.org/10.1130/0091-7613(1987)15<22:RMPEOT>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Francis Ö. Dudás, Richard W. Carlson, David H. Eggler; Regional Middle Proterozoic enrichment of the subcontinental mantle source of igneous rocks from central Montana. Geology 1987;; 15 (1): 22–25. doi: https://doi.org/10.1130/0091-7613(1987)15<22:RMPEOT>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Trace-element and Pb, Nd, and Sr isotope analyses demonstrate that the Tertiary subalkalic and alkalic igneous rocks of the Crazy Mountains, Montana, derive from separate mantle sources. The alkalic source region is heterogeneous and strongly enriched in most incompatible elements. Although it has Sr isotopic compositions near bulk earth values, it has low 206Pb/204Pb (16.5–17.4) and ϵNd (−2.6 to −153). The source of the subalkalic rocks is less enriched but is similar isotopically, except that ϵNd ranges between −13.4 and −17.1, Model ages based on Nd and Pb isotopic data show that these mantle source regions have a multistage differentiation history that probably commenced shortly after stabilization of the Archean crust at 3.0 Ga. The isotopic character of both alkalic and subalkalic sources was significantly influenced by a mantle-enrichment event at 1.5–1.8 Ga.Comparison of the Crazy Mountains with other Cretaceous to Holocene igneous centers in Montana and Wyoming shows that the Middle Proterozoic enrichment event is recorded from the Bearpaw Mountains to the Leucite Hills. This regionally extensive ancient subcontinental mantle is complementary to mid-ocean ridge and ocean island basalt sources and is distinct from the sources of many other alkalic rocks. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Publication Year: 1987
Publication Date: 1987-01-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 111
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