Intermittent 1630–1220 Ma magmatism in central Mazatzal province: New geochronologic piercing points and some tectonic implications
- O. Tapani Rämö1,
- Virginia T. McLemore2,
- Michael A. Hamilton3,
- Paula J. Kosunen4,
- Matt Heizler5 and
- Ilmari Haapala6
- 1Department of Geology, University of Helsinki, P.O. Box 64, FIN-00014, Finland
- 2New Mexico Bureau of Geology and Mineral Resources, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, USA
- 3J.C. Roddick Ion Microprobe (SHRIMP II) Laboratory, Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada
- 4Department of Geology, University of Helsinki, P.O. Box 64, FIN-00014, Finland
- 5New Mexico Bureau of Geology and Mineral Resources, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, USA
- 6Department of Geology, University of Helsinki, P.O. Box 64, FIN-00014, Finland
Abstract
The northern Burro Mountains in southwestern New Mexico reveal three distinct, intimately juxtaposed Mesoproterozoic magmatic suites in southern Laurentia. At 1633 Ma, the newly formed Mazatzal crust was intruded by tholeiitic diabase with a depleted-mantle–type Nd isotope composition but with enriched incompatible trace element abundances. A potassic granite-minette suite was emplaced ca. 1460 Ma, and a tholeiitic A-type granite-anorthosite suite intruded ca. 1225–1220 Ma. The diabase-minette-anorthosite sequence and the associated silicic rocks record dominantly juvenile additions to the cratonic margin and imply subcontinental enrichment events ca. 1650 Ma (accretion), prior to 1460 Ma (potassic metasomatism), and ca. 1220 Ma (magmatic underplating). The latter two may have been controlled by a major transcurrent structure along the south margin of Laurentia.
Footnotes
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↵GSA Data Repository item 2003040, Tables DR1–DR3, analytical methodology and data sets, is available from Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301-9140, editinggeosociety.org, or at www.geosociety.org/pubs/ft2003.htm.
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- Accepted December 20, 2002.
- Received September 28, 2002.
- Revision received December 17, 2002.
- Geological Society of America
