Comparative study of felsic magmas with explosive or not explosive eruption

(1)在古地磁和岩石学研究的基础上，估算了该区的四个熔岩穹隆。桑贝形成于3.7-3.8Ka。在英安岩碎屑和熔岩中发现具有热剩余磁化自逆转作用的赤钛铁矿。Sanbe和Mt.(2)通过模拟火山碎屑流中的热条件，开展了利用夹带碳化木材的H/C比估算火山碎屑流侵位温度的实验室实验。H/C比与温度有很强的相关性。用天然炭化木材和全新世火山碎屑流沉积的古地磁阻挡温度进行了H/C测温。用这些方法估算了距桑贝火山导管约5.5公里的台黑寨火山碎屑流矿床的侵位温度为530-560℃。(3)在岩浆的产生和上升过程中，在与沉积物有关的火成岩中发现了有机质，如S式长英质岩石、高镁安山岩、板片熔融形成的岩石和沉积成因混合岩。(4)实验研究了长英质岩浆中沉积烃的转化及其在地壳中部条件下的固化过程。所有实验产物中的碳质物质不仅以碳酸盐和石墨的形式存在，而且以固态碳氢化合物的形式存在，表明发生了聚合反应。

(1) On the basis of paleomagnetic and petrographical studies, it estimates that the four lava domes of Mt. Sanbe formed at 3.7-3.8 Ka. Hemoilmenite showing self-reversal of thermo-remnant magnetization was found in dacite clasts and lava from Mt. Sanbe and Mt. Daisen.(2) Laboratory experiments aimed at allowing estimation of emplacement temperatures of pyroclastic deposits flows using H/C ratios of entrained carbonized wood were carried by simulating the thermal conditions in pyroclastic flows. H/C ratios show a strong correlation with temperature. H/C thermometry was tested by natural carbonized woods and paleomagnetic blocking temperatures from Holocene pyroclastic flow deposits. Emplacement temperatures of Taiheizan pyroclastic flow deposits about 5.5km from the conduit of the Sanbe volcano were estimated 530-560℃ by these methods.(3) Organic matter was found in igneous rocks related to sediments during the generation and ascent of magmas, such as S-type felsic rocks, high Mg andesite, rocks formed by slab melting and sedimentary origin migmatite.(4) Experiments were carried out to examine transformation of sediment-derived hydrocarbons contained in felsic magma and during its solidification at middle crustal condition. Carbonaceous materials remained in all experimental products, not only as carbonate and graphite but also as solid state hydrocarbon, indicating that polymerization occurred.