ISOTOPIC CONSTRAINTS (Pb, Rb-Sr, Sm-Nd) ON THE SOURCES OF EARLY CAMBRIAN PEGMATITES WITH BORON AND BERYLLIUM MINERALS IN THE LARSEMANN HILLS, PRYDZ BAY, ANTARCTICA
Roland Maas, Edward S Grew, Christopher J Carson
CANADIAN MINERALOGIST | MINERALOGICAL ASSOC CANADA | Published : 2015
The Brattstrand Paragneiss, a highly deformed Neoproterozoic granulite-facies metasedimentary sequence, is cut by three generations of ∼500 Ma pegmatite. The earliest recognizable pegmatite generation, synchronous with D2-3, forms irregular pods and veins up to a meter thick, which are either roughly concordant or crosscut S2 and S3 fabrics and are locally folded. Pegmatites of the second generation, D4, form planar, discordant veins up to 20-30 cm thick, whereas the youngest generation, post-D4, forms discordant veins and pods. Clear associations of pegmatites with broadly coeval granites are lacking. The D2-3 and D4 pegmatites are abyssal class (boron-beryllium subclass) characterized by g..View full abstract
Awarded by NSF
Fieldwork during the 2003/2004 field season and laboratory expenses were supported by NSF grants OPP-0228842 and EAR-0837980 to the University of Maine and ASAC 2350 to CJC and ESG. CJC publishes with permission of the CEO, Geoscience Australia, Geocat 82308. We thank Davis Station leader Bob Jones and members of the 2003-2004 Australian National Antarctic Research Expedition for logistic support. We thank Steve Boger for his comments on the geologic aspects and journal reviewers Peter Nabelek and Paul Tomascak for their detailed and thoughtful reviews of the manuscript.