2024-03-28T15:26:09Z
https://meral.edu.mm/oai
oai:meral.edu.mm:recid/5641
2022-03-24T23:14:46Z
1582963739756
1582963739756:1582967109396
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Magma Mixing and Tectonic Discrimination of Kyaukka Taung Basalts, Monywa Township, Sagaing Region
Myo Win Thant
Kyaukka Taung area is situated 7 miles east of Monywa, Monywa Township, Sagaing Region. It is situated exactly in the eastern trough of the Central Myanmar Tertiary Basin, Shwebo-Monywa plain province. The peculiarly-shaped mound of the Kyaukka Taung is in the form of a flow that capped on the Pegu strata. Macroscopically, the basalt at Kyaukka taung is compact, fine-grained, and dark-green, dark-grey, reddish-grey in color, some of which are quite vesicular. Microscopically, Kyuakka basalts are porphyric and consist of olivine, plagioclase and diopside crystals. Ground masses are irregular and consist of feldspar laths, olivine and magnetite. The volcanic occurrence of Kyaukka taung capped the crests of the anticline and traversed by faults. In the K2O vs. SiO2 diagram, magmatic affinity of the basalts fall within the calc-alkaline series. In the total alkali (Na2O + K2O) vs. silica (SiO2) diagrams, the basaltic samples fall between the field of trachy-basalt and basalt, but many of them fall in the basalt field. In Harker’s variation diagram. The decrease in MgO, FeO*, and CaO as SiO2 increases is consistent with the removal of early-forming minerals from the cooling liquid. So, fractional crystallization is responsible. But, Al2O3 and K2O also increase as SiO2 increases. K2O, TiO2, and P2O5 are relatively rich in the samples, and they are incompatible elements. Thus, crystal fractionation is not the only process and mixing of mafic magma (mantle melts) and silicic magma (crustal melts) may also be another dominant process. These characters are correspondent with subduction-related magma evolution. To infer the original tectonic/igneous setting, recently tested discrimination diagram of Vermeesch (2005) is used. In this discrimination scheme, all of the basalt samples fall in island-arc basalts (IAB) field.
2020-05-30
http://hdl.handle.net/20.500.12678/0000005641
https://meral.edu.mm/records/5641