| Abstract: | Geochemical and new isotopic (U-Pb, Sm-Nd) data on the Mesoproterozoic metaigneous complexes of the Rayner Province in central
East Antarctica (Enderby Land-Kemp Land and the northern Prince Charles Mountains) are presented. These territories are mainly
composed of amphibolite-to-granulite-facies orthogneisses, many of which are Y-depleted tonalite gneisses and mafic schists.
The igneous complexes of their protolith are largely products of anatexis of the lower crust; mantle-derived and upper crustal
rocks are less abundant. The geochemical features of the mafic rocks indicate that they crystallized from high-temperature
plume-related mantle melts and low-temperature lithospheric melts. As follows from the published and new Nd model ages, the
Rayner Province formed and evolved over the Paleo-to-Mesoproterozoic in the regime of accretionary and collisional tectonics
with predominance of accretion of the juvenile Paleoproterozoic crust between 1500–2400 Ma. New data show that in the northern
Prince Charles Mountains, granite-gneiss protoliths were emplaced ca. 1040 and 930 Ma ago. The Rayner Province is considered
to be a long-living mobile belt formed as a result of collision of Paleoproterozoic island-arc terranes and Archean blocks
amalgamating into a continental massif 1050–1000 Ma ago in the course of the growth of the Rodinia supercontinent. In the
northern Prince Charles Mountains, thermal processes related to magmatic underplating at the base of the crust were probably
important. |
