New findings of alkaline-ultramafic dykes in the Prince Charles Mountains: Age and composition
Summary Dykes of phlogopite-bearing alkaline picrite discovered in 2004 in the southern part of Mt. Meredith are comparable through their mineralogy and geochemistry with typical mica-bearing kimberlites and distinctive from the well-known alkaline-ultramafic bodies in Jetty Peninsula and along the...
| Main Authors: | , , |
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.573.5815 http://pubs.usgs.gov/of/2007/1047/ea/of2007-1047ea195.pdf |
| Summary: | Summary Dykes of phlogopite-bearing alkaline picrite discovered in 2004 in the southern part of Mt. Meredith are comparable through their mineralogy and geochemistry with typical mica-bearing kimberlites and distinctive from the well-known alkaline-ultramafic bodies in Jetty Peninsula and along the shores of Radok Lake. At the same time, temperature and pressure estimations of their crystallization- 990˚C and 18-26 kbar and the time of intrusion – 122 Ma and primary isotope signatures (87Sr/86Sri = 0.7048 – 0.7051, εNd =-1.0 –-0.6) lead us to infer a similarity to the rocks of the Beaver Lake Province. Taking into consideration this fact and supposing that their formation is connected with development of Lambert-Amery rift in Mesozoic time and mantle activity under the influence of the mantle plume (Kerguelen plume?) which caused Gondwana breakup, we suggest that these alkaline-ultramafic bodies make up a single magmatic province, similar in time and development to the alkaline-ultramafic-carbonatite Shillong Province in India. |
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