Heat Flows off Southwest Taiwan: Measurements Over Mud Diapirs and Estimated from Bottom Simulating Reflectors

A Wannienta basalt from Kuanyinshan,northern Taiwan,is studiedusing a high temperature furnace at atmospheric pressure.The purpose ofthis study is to investigate the crystallization sequence of the phenocrysts,to analyze the chemical compositions of the phenocrysts,and to estimatethe evolution trend of the magma in the Kuanyinshan area.Fifteen runs are made to locate the liquidus temperature,the solidustemperature,and the melting interval of the Wannienta basaltic magma.The experimental temperatures range from 1087℃ to 1281℃.The durationisfrom five hours to nineteen hours.Compositions of glasses and phenocrystsare analyzed with an electron microprobe.The experimental results show that the liquidus temperature is locatedat 1270℃ and the solidus temperature is estimated to be close to 1080℃.The melting interval is about 190℃.The liquidus minerals are oxides withcompositions in spinel series.The following crystallized phase is olivine atabout 1217℃.Plagioclase and clinopyroxene appear,respectively,at about1178℃ and 1137℃.The evolution of the residual magma shows the chemicaltrend as:enrichment in silicon,aluminum,and alkalis;and depletion incalcium,iron,and magnesium with the decreasing temperature.The fractionationtrend of the Kuanyinshan volcanic series is similar to the variationtrend of the residual magmas.It implies that the depth for the fractionalcrystallization of the Wannienta basaltic magma to produce andesitescould be modeled at low pressure.The fractionates to produce biotitehornblende andesitic magma could be oxides,olivine,plagioclase,andclinopyroxene.

並列關鍵字

Heat Probe ； Heat Flow ； Mud Diapir ； BSR ； Southwest Taiwan

國際替代計量

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