Correlating multiple deformation events across the Mesoproterozoic NE Australia using foliation intersection axes (FIA) preserved within porphyroblasts

Sayab, Mohammad (2008) Correlating multiple deformation events across the Mesoproterozoic NE Australia using foliation intersection axes (FIA) preserved within porphyroblasts. Gondwana Research, 13 (3). pp. 331-351.

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Abstract

Foliation Intersection/Inflection Axes within porphyroblasts (FIAs) allow the chronological and kinematic linking of deformation episodes with associated metamorphism. Measurement of FIAs in the Mesoproterozoic Eastern Fold Belt (EFB) of the Mount Isa Inlier, NE Australia, has revealed phases of deformation and metamorphism that could not previously be distinguished from one another. Both the 'asymmetry switch' and 'FitPitch' FIA measurement techniques have been applied to key localities of polymetamorphosed and multiply deformed EFB, and they yielded the same result. These independent techniques have revealed (1) E–W trending structures that formed during N–S bulk shortening (D1) and associated metamorphism (M1) formed during a period of orogenesis (O1) and N–S oriented structures that formed during E–W bulk shortening (D2) and associated metamorphism (M2) during a period of orogenesis (O2), and (2) the crustal scale tectonic processes associated with polymetamorphism. Middle to upper amphibolite facies metamorphic conditions occurred during O1 with crustal thickening followed by near-isothermal decompression leading to low-pressure/high-temperature (LP/HT) conditions with the emplacement of Williams and Naraku Batholiths around 1550 Ma. This was followed by a second period of middle-to upper-amphibolite facies metamorphism, O2. This history not only correlates better across the EFB, but also with the tectono-metamorphic model recently proposed for the Mesoproterozoic Georgetown Inlier of the north Australian Craton.

Item ID: 10604
Item Type: Article (Refereed Research - C1)
Keywords: Mount Isa; Eastern Fold Belt; FIAs; porphyroblasts; inclusion trails
ISSN: 1342-937X
Date Deposited: 14 Apr 2010 22:16
FoR Codes: 04 EARTH SCIENCES > 0403 Geology > 040312 Structural Geology @ 50%
04 EARTH SCIENCES > 0403 Geology > 040313 Tectonics @ 50%
SEO Codes: 84 MINERAL RESOURCES (excl. Energy Resources) > 8401 Mineral Exploration > 840102 Copper Ore Exploration @ 100%
Citation Count from Web of Science Web of Science 12
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