IANIGLA   20881
INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
U-Pb LA-ICPMS COLUMBITE-TANTALITE AGES FROM THE PAMPEAN PEGMATITE PROVINCE: PRELIMINARY RESULTS
Autor/es:
VON QUADT, A.; GALLISKI M. A.
Lugar:
Mendoza
Reunión:
Simposio; 5th International Symposium on Granitic Pegmatites; 2011
Resumen:
The granitic pegmatites have the same cooling path like their host rocks after magmatic crystallization.During this process, subsolidus hydrothermal reequilibration tends to disturb some isotopic systems. Consequently, the K-Ar method applied on muscovite or K-feldspar at its best only gives the cooling age of the pegmatites. These ages for the pegmatites of the Pampean pegmatite province were broadly grouped in three major periods based on K-Ar dates by Rinaldi & Linares (1973) and Galliski & Linares (1999). However, since more precise methods are needed for bracketing  these ages of pegmatite intrusion, we address this research to date primary phases of rare-element granitic pegmatites, specifically columbite-group minerals (CGM), which isotopic system usually remain undisturbed after their magmatic crystallization. Romer & Wright (1992) showed that CGM are a suitable material for U-Pb dating. Thermionen mass spectrometer analyses (TIMS; Romer & Smeds 1994, Romer & Lehmann 1995, Romer et al. 1996) or Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS; Smith et al. 2004)analyses were shown as appropriate methods to determine the crystallization age of CGM. Combined U-Pb dating with major, trace and REE element analysis, additionally give a fi ngerprint for tracing the provenance of some CGM ores (Melcher et al. 2008). This approach was shown to be a useful tool for certifi cate the origin of CGM (coltan) produced in confl ictive areas of Africa or elsewhere.