Mechanics Of Lava Flow From The Modern Volcanoes In The Wudalianchi Area

Physical properties of lava, flow rate of magma as it effuses from the underground and its surrounding environmental factors, play the important roles in learning the transportation and cooling of lava flow and dynamical mechanics. In reality, it is an difficult to obtain the data of the lava flow form the active volcanoes, but the flow features preserved on the surface or in the interior of lave flow give the good phenomena and facts to study the lava flow quantitatively.On the basis of the volcanic geology and the idea of geological fluid mechanics, the flow stages and features, and the crystallization and cooling of lava flow from the Laoheishan Volcano are studied in this thesis. According to the field work and some laboratory work, as well as the previous data from the other geologists, some conclusions have been come to.1. the relationships between the different lava flow units and their relations to the pyroclast sequences can be considered as the direct evidence.2. Using the GPS and GIS technology, the lava flow units in the local area of Laoheishan Volcano are mapping on the basis of large scale. In comparison with the 1/25000 Map of Volcanic Geology, the LS₁ units lying to Laoheishan Volcano exist some problems.3. The crystallization sequences from olivine, clinopyroxe, leucite and alkali feldspar with cooling are further confirmed according to the petrography and mineralogy of the different lava phases from the Laoheishan working area. The composition of volcanic glass gradually decreases Fe_T, Mg and Ca with the increasing crystalinity. The olivine from the Laoheishan is chrysolite.4. Through a little improvement of cooling model of lava flow, the cooling processes of cylinder lava flow in the lava tube has been studied. It is preliminarily concluded that the rate of solidification in the interior phase is slower and then its crystallization is more complete than the one in the surface phase.