Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

The Role of Magmatic Differentiation and Crustal Partial Melting in the Genesis of Acidic Volcanic Rocks, South of Danesfahan

Document Type : Original Research Paper

Author
Mohammad Reza Ghorbani
Tarbiat Modarres University, Tehran, Iran
Abstract
       Geochemical characteristics and petrography of the acidic volcanic rocks from the South of Danesfahan indicate that these rocks are products of different petrogenetic processes. Magmatic differentiation through fractional crystallization has played the main role in the evolution of majority of acidic rocks. These rocks include the rhyolites with the following features: 1)porphyritic texture, 2)negative anomaly of Eu, and 3)decreasing LILE and increasing REE contents with increasing silica. A few of acidic rocks from the study area show characteristics implying their generation through partial melting of the upper crustal rocks. These include the rhyolites with the following features: 1)vitrophyric or perlitic texture, 2)lack of negative anomaly of Eu, and 3)the highest LILE/REE  and LREE/HREE ratios amongst the acidic volcanic rocks.
Keywords
Magma
Crystallization
Melting
Crust
Acidic volcanic rocks
Geochemistry
Danesfahan

Subjects

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Scientific Quarterly Journal of Geosciences
Volume 14, Issue 55
Spring 2005, Vol.14, No. 55
Spring 2005
Pages 114-119