Thin Section: Laf105

Title: Thin Section: Laf105
Description: This thin section contains some feldspar and quartz microphenocryst surrounded by a matrix of volcanic glass and some white needle-shaped microlites. Oikocryst is present, with feldspar inclusion. Many feldspars show oscillatory zoning and polysynthetic twinning, which suggests that the environment is not stable. Fiamme texture indicate that the original are formed when ignimbrites are emplaced at high temperature, and the lower portions typically become welded by the internal heat in the settled pile to a vary hard rock. They can usually be found in a pyroclastic flow deposit. Most of the crystal is euhedral or subhedral, and some crystal has a spherulitic texture. Therefore, this thin section might originate from a silicic pyroclastic flow deposit that cools quickly.
Creator: 8585
Type: Igneous rock
Mediator: Tamara Carley

Media: https://exhibits.lafayette.edu/geology/files/original/979221f91dee810a0b5c602c366a04d5.JPG; https://exhibits.lafayette.edu/geology/files/original/46109a5ded0920b86d616d2d4a55c766.JPG; https://exhibits.lafayette.edu/geology/files/original/adbd262e0de6373ff3ac9ff7c79f4415.JPG; https://exhibits.lafayette.edu/geology/files/original/98a06437c2d9b45f0ff3d465b4a2b03f.JPG; https://exhibits.lafayette.edu/geology/files/original/fd49c3d6bb162d49fa673bd6524c81dd.JPG; https://exhibits.lafayette.edu/geology/files/original/4c16d97dc2fba02c2869fa0d3255c15e.JPG; https://exhibits.lafayette.edu/geology/files/original/770bd49704e27bcd423202d61c179c21.JPG