New findings of alkaline-ultramafic dykes in the Prince Charles Mountains: Age and composition

• Main Authors: A. A. Laiba, B. V. Belyatsky, N. V. Rodionov
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Amery; Beaver Lake; Jetty Peninsula; Kerguelen; Meredith; Prince Charles Mountains; Radok Lake
• 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 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.