Writers : Monfaredi, Behzad; Masoudi, Fariborz
Refference : The 26th Symposium on Geoscieences;Tehran
Publishing Year : 1386

Abstract :
Eocene and Paleocene volcanic units are outcropped in south Jajarm (Sabzevar north ophiolite). Main volcanic rocks are andesite, andesitic-basalt, dacite, andesitic-dacite, tuff, andesitic breccia tuff. In microscopic examination, main minerals of sample are plagioclase and pyroxene are in glassy matrix with main porphyritic texture.
Crystal size distribution (CSD) of plagioclase in Eocene andesitic-basalt sample has been studied to determine residence time and nucleation rate. Calculation in basis of crystal size distribution diagram slope of plagioclase reveal residence time of crystals (t), and residence time was 1 8.54yr. Furthermore, nucleation rate is calculated from interception of diagram with population density pivot of crystal. Therefore, nucleation rate obtained 9/55*I0-10mms-1.
Subject List : CSD method, Plagioclase