Geochemistry and petrogenesis of high-Mg tholeiites and lamprophyres in the Vestfold Hills, Antarctica ...
The Vestfold Hills, Antarctica, an ice-free region of ea. 400 km\\(^2\\), is a well exposed terrane of deep Archaean and Proterozoic crust which has been strongly interfolded and transposed. Between 2350 and 1100 Ma a dense network of mafic dykes intruded at mid- to upper crustal depths. Crosscuttin...
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| Format: | Thesis |
| Language: | unknown |
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University Of Tasmania
2023
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| Online Access: | https://dx.doi.org/10.25959/23243336 https://figshare.utas.edu.au/articles/thesis/Geochemistry_and_petrogenesis_of_high-Mg_tholeiites_and_lamprophyres_in_the_Vestfold_Hills_Antarctica/23243336 |
| Summary: | The Vestfold Hills, Antarctica, an ice-free region of ea. 400 km\\(^2\\), is a well exposed terrane of deep Archaean and Proterozoic crust which has been strongly interfolded and transposed. Between 2350 and 1100 Ma a dense network of mafic dykes intruded at mid- to upper crustal depths. Crosscutting relationships distinguish 9 different dyke sets intruded in three magmatic episodes. These three episodes exhibit distinct directional trends suggesting rotation of the regional crustal stress field over the period 2350 to 1150 Ma. During the first magmatic episode high-Mg tholeiites were emplaced at about 2350 Ma together with Fe-rich tholeiites. A second magmatic period has been inferred at ~1800 Ma in which a further set of Fe-rich tholeiites was emplaced. Radiogenic dating of the 1800 Ma dykes is not well constrained and field observations from this study did not clarify the relationship of these dykes to the older (2350 Ma) Fe-rich tholeiites. A third magmatic episode, which occurred between 1350 and 1150 ... |
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