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浙江桐庐和寿昌中生代火山事件分别为同源和异源多期火山活动。由下地壳部分熔融产生的钙碱性岩浆,在火山岩浆房内曾发生明显分异。桐庐中生代火山岩浆房的深度约为10—11km(上限值),火山岩浆中含水4—6(重量％)。在火山活动演化史中岩浆房上部的酸性分异岩浆,fo_2相对较高,P总(H_2O)较低,先行喷出地表,形成流纹质、英安流纹质灰流凝灰岩。层位稍下的中酸性分异岩浆稍后挤出地表或挤入近地表浅部,形成侵出相碎斑英安岩。岩浆演化过程中,上升岩浆的基性度、P总和挥发组分含量不断增高,fo_2渐趋降低,从而导致矿物结晶温度逐渐降低。岩浆房下部的中性分异岩浆,fo_2最低(10~(-18.29)bar),P总(H_2O)最高(300—320MPa),最后上侵,形成石英二长岩—石英二长闪长岩等浅成侵入体。寿昌中生代钙碱性火山岩浆房的位置明显较浅(深度上限值约为2km),岩浆中水蒸汽含量偏高,从而造成该区中生代火山活动以爆发型喷发为主。
The Tonglu and Shouchang Mesozoic volcanic events in Zhejiang Province were respectively homologous and heterogenous multi-phase volcanic activities. The calc-alkaline magma, which is partially melted by the lower crust, has been clearly differentiated in the volcanic magma chamber. The Tonglu Mesozoic volcanic magma chamber has a depth of about 10-11 km (upper limit) and 4-6 vol.% Of volcanic magma. In the evolutionary history of volcanic activity, the acid-differentiated magma in the upper part of the magma chamber has a relatively higher fo_2 and a lower total P 2 O (H 2 O). The magma is discharged ahead of the surface to form a rhyolite and an English rhyolite gray-tuff. Slightly below the level of acidic sub-magma later squeezed out of the surface or squeezed into the shallow near the surface, the formation of the invasion of facies plagioclase diorite. In the process of magmatic evolution, the basicity of the ascending magma, the content of the total volatile component of P increased continuously, the fo_2 gradually decreased, and the crystallization temperature of the mineral gradually decreased. The neutral magma in the lower part of the magma chamber has the lowest fo_2 (10 ~ (-18.29) bar) and the highest (H_2O) of 300_320MPa, finally it intrudes into quartz monzorite-quartz diorite Into other shallow into the body. The Shouchang Mesozoic volcanic magma chamber is located at a shallower depth (with an upper limit of about 2km) and a high water vapor content in the magma, resulting in the eruption of Mesozoic volcanic activity in the area dominated by explosive eruptions.