Abstract
Partial-melting experiments, at 1.0-3.0 GPa and 900-1100 degrees C, were conducted on two greenstones of Early Archaean (Hadean) age from the Nuvvuagittuq Complex of northern Quebec. For comparison, similar experiments were also conducted on a modern boninite (from the North Tongan Arc) with compositional similarities to the Nuvvuagittuq greenstones. Partial-melts produced by these experiments are compositionally similar to some TTGs, including a 3.66 billion year old tonalite that encloses the Nuvvuagitttuq Complex. Because the degree of melting needed to produce the tonalitic melts is comparatively high (> 30 %), the relative concentrations of most incompatible elements in the melts are similar to those in their greenstone and bonninite parent rocks. Thus many of the incompatible element characteristics of TTGs may have been inherited from previously fractionated source rocks that already possessed similar characteristics. If this was true, early continental crust production may have been closely associated with some form of crustal re-cycling that duplicated many of the magmatic consequences of modern plate tectonics.
Original language | English |
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Pages (from-to) | 407 |
Number of pages | 407 |
Journal | Mineralogical Magazine |
Volume | 75 |
Issue number | 3 |
Publication status | Published - 2011 |
Event | Goldschmidt Conference (21st : 2011) - Prague, Czech Republic Duration: 14 Aug 2011 → 19 Aug 2011 |