Scholarly record
GROWTH PATTERNS AND EMPLACEMENT OF THE SILICIC LAVA DOMES IN SOUTHWEST OF ARDABIL, IRAN
Abstract
The area under study is located in east Azerbaijan and southwest of Ardabil. In this area the volcanic rocks are placed over the Oligocene and lower Miocene clastic sedimentary rocks and under lower Pliocene epiclastic sedi ments. Therefore, their age is middle and upper Miocene. These volcanic rocks have been extruded in dome shape from the fissures of an eruptive caldera. These domes are rich in silica. From the boundary to the center of caldera, these domes are categorized into three types with regard to their formation mechanism. First, there are the domes located towards the edge. They have dacitic composition and have been extruded in a single stage. Different parts of these domes are similar in general. Second, there are the domes located between the edge and center of the caldera. These domes are rhyoda citic in composition and have extruded in multiple stages and are layere d. Generally, the layers of these domes are similar. The third types are placed in th e center of the caldera, have rhyolitic composition and, like the previous type, have been extruded in several stages and are layered. However, the layers are quite different from each other. Field evidence and geochemical studies are suggestive of the existence of a genetic association between the magma of these domes. Differentiation has triggered the variety in the chemical composition and consequently the extrusion mechanism in different parts of the calde ra. Chemical composition, viscosity, temperature, the amount of volatil e materials in magma and the difference in density of magma and the surrounding rocks are among the most significant factors which determine extrusion mechanism and formation of silicic domes in the area.
Publication Impact Profile
- Captures
- Mendeley - Readers: 2
Publication details
References7
Best, M .G, Igneous and Metamorphic Petrology, Freeman and Company, 1982.
Cas, R. A. F. & Wright, J.V., Volcanic Successions, Modern and Ancient, Unwin Hyman, 1988.
Fink, J. H., Structure and emplacement of a rhyolitic obsidian flow: Little Glass Mountain Medicine Lake Highland, northern California, Geol. Soc. Am. Bull., 94: 262- 280, 1983.
Fisher, R. V. and Schmincke, H. V., Pyroclastic Rocks, Springer - Verlag, 1984.
Henry, C. D., Price, J. G., Rubin, J. N. and Laubach, S. E., case study of an extensive silisic Lava: the Braks Rhyolite . Trans – Pecos Texas., J. Volcanol. Geotherm. Res., 43: 113 - 132, 1990.
Middelmost, E. A. K., Magmas and magmatic rocks, Longman. London, 1985.
Richardson, S., The geology of southern Lipari, with particular reference to the rhyolite tholoids in the extreme south of is land. Unpubl., B. Sc. Thesis, University of Leeds, 1978.
View or Download full articleAccess options
SWS access login
Login as SWS Scientific CommitteeLogin as SWS Scientific PartnerLogin as SWS AuthorAuthors and approved SWS contributors will read and export their own linked papers after identity matching by SWS profile, email and SGEM GlobalID.
For librarian assistance: [email protected]
Purchase Instant Access
- Article can be downloaded after successful payment.
- Article may be used according to SWS library access terms.
- Article cannot be redistributed.