The evolution of bubble size distributions (BSD) in Qorveh-Bijar Quaternary volcanism, East of Kurdistan

Scoria cones are one of the main parts of East of Kurdistan volcanoes. Olivine, Pyroxene, Plagioclase and Biotite are main phonocrystals with Amygdaloidal-glassy matrix. This paper was studied processes of bubbles nucleation and grow during the eruption of scoria's unite using the Bubble Size Distribution (BSD) method including study of population density, bubbles volume, 3D modeling, nucleation and bubble growth. For selected sample from different cone, in total was measured 3623 bubbles and drawn that bubbles volumes calculated from 40 to 85 percent. Using the 2D bubbles shape renovated 3D bubbles schematic shape and compared together. Most population for four samples bubbles shapes are near to sphere and for other four samples are ellipsoid. Longest ellipsoid bubbles shape has 1:3.2:8 diagonals ratio that it’s flat ellipsoid. The longest diameter (L) is perpendicular to the surface and parallel to lower pressure dictated on magma and bubbles could be growth more than other sides. Presence of 2-5 peaks in frequency distribution versus bubble size diagram, suggesting unimodal, polymodal, exponential and power low events for bubbles generation in the east of Kurdistan Scoria's. Nucleation density increased from first to lasts generation but bubbles growth reduced. Recur of bubble forming in macroscopic samples, microscopy, SEM and nucleation and grow model suggested fractal model.