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7462618 
Journal Article 
Geology, age and origin of the Mount Willing area (Prince Charles Mountains, East Antarctica) 
Mikhalsky, EV; Laiba, AA; Beliatsky, BV; Stuwe, K 
1999 
Yes 
Antarctic Science
ISSN: 0954-1020
EISSN: 1365-2079 
11 
3 
338-352 
English 
WOS:000086753000009 
Mount Willing in the Prince Charles Mountains (East Antarctica) is part of the Fisher Volcanoplutonic complex which formed as part of the global-scale Grenvillian mobile belt system. Mount Willing is composed of four rock complexes: 1) a metamorphic sequence, 2) gabbro intrusions, 3) deformed felsic intrusives, and 4) abundant post-metamorphic dykes and veins. Three rock types constitute the metamorphic sequence: amphibole-biotite felsic plagiogneiss, mafic to intermediate biotite-amphihole schist, and biotite paragneiss. The bulk composition of the mafic schists classifies them as tholeiitic basalts, and rarely as basaltic andesites or andesites. Index mg ranges widely from 47 to 71. Concentrations of TiO(2), P(2)O(5), and high-field strength elements are high in some rocks. These rocks are thought to have been derived from enriched (subcontinental) mantle sources. Sm-Nd and U-Pb isotopic data indicate a series of Mesoproterozoic thermal events between 1100 and 1300 Ma. In particular, these events occurred at 1289 +/- 10 Ma (volcanic activity), at 1177 +/- 16 Ma (tonalite intrusion), at 1112.7 +/- 2.4 and at 1009 +/- 54 Ma (amphibolite facies metamorphic events). Rb-Sr systematics also indicates a thermal overprint at 636 +/- 13 Ma. Mafic schists show low initial (87)Sr/(86)Sr ratios between 0.7024 and 0.7030. Felsic rocks show higher Sr(1) values between 0.7037 and 0.7061. Basaltic andesite metavolcanic and plutonic rocks form a calc-alkaline evolutionary trend, and probably originated from subduction-modified mantle sources in a convergent plate margin environment. An oceanic basin may have existed in central Prince Charles Mountains about 1300 Ma ago and was closed as a result of continental collision around 1000 to 800 Ma. 
Antarctica; geochemistry; metamorphism; Proterozoic; volcanic rocks