Shallow and deep reservoirs involved in magma supply of the 1944 eruption of Vesuvius
Shallow and deep reservoirs involved in magma supply of the 1944 eruption of Vesuvius
复制标题
参与 1944 年维苏威火山喷发岩浆供应的浅层和深层储层
DOI：
10.1007/s004450050262
复制
发表时间：
1999
影响因子：
3.5
通讯作者：
A. Sbrana
中科院分区：
文献类型：
--
作者：
P. Marianelli;N. Métrich;A. Sbrana
1944年维苏威火山喷发期间，火山喷发动力学发生了突然变化，这与岩浆成分的变化有关。k -花斑质岩浆在喷发期和第一次熔岩喷泉喷发，而强斑状k -花斑质岩浆则在更强烈的熔岩喷泉喷发。熔体包裹体组成（主要元素和挥发性元素）表明岩浆在不同压力下发生了分化。富挥发性k - tephric熔体（可达3wt）。% H2O, 3000 ppm CO2, 0.55 wt。% Cl)在高于300 MPa的总流体压力下，通过透辉石和橄榄石的结晶作用，演化成k -音质成分。这些岩浆形成了一个非常浅的储层。低挥发性钾-音辉质岩浆（H2O<1 wt.%）的低压分异包括混合、开放体系脱气和白长石、盐长石和斜长石的结晶。这次喷发是由富含挥发物的岩浆群从11-22公里深处进入浅岩浆库引发的。火山喷发的第一阶段代表了浅层水库的部分排空，浅层水库的顶部在火山大厦内。新到达的岩浆与浅层储层中的岩浆混合，迫使火山喷发从喷涌阶段过渡到熔岩喷泉阶段。
Abstract During the 1944 eruption of Vesuvius a sudden change occurred in the dynamics of the eruptive events, linked to variations in magma composition. K-phonotephritic magmas were erupted during the effusive phase and the first lava fountain, whereas the emission of strongly porphyritic K-tephrites took place during the more intense fountain. Melt inclusion compositions (major and volatile elements) highlight that the magmas feeding the eruption underwent differentiation at different pressures. The K-tephritic volatile-rich melts (up to 3 wt.% H2O, 3000 ppm CO2, and 0.55 wt.% Cl) evolved to reach K-phonotephritic compositions by crystallization of diopside and forsteritic olivine at total fluid pressure higher than 300 MPa. These magmas fed a very shallow reservoir. The low-pressure differentiation of the volatile-poor K-phonotephritic magmas (H2O<1 wt.%) involved mixing, open-system degassing, and crystallization of leucite, salite, and plagioclase. The eruption was triggered by intrusion of a volatile-rich magma batch that rose from a depth of 11–22 km into the shallow magma chamber. The first phase of the eruption represents the partial emptying of the shallow reservoir, the top of which is within the volcanic edifice. The newly arrived magma mixed with that resident in the shallow reservoir and forced the transition from the effusive to the lava fountain phase of the eruption.