Thin Section: Picrite

Title: Thin Section: Picrite
Description: Thin section textures:
Porphyritic texture occurs when magma cools slowly and then quickly as it is extruded after starting to cool. This involves a matrix and the presence of crystals in the sample.
Phenocrysts are larger crystals set within a fine matrix. In this sample, there are many olivine phenocrysts formed by the magma cooling slowly at first before being extruded.
Matrix or groundmass refers to the finer-grained component of this porphyritic sample, which would have cooled quicker than the larger, well-formed crystals.
Cumulophyric texture refers to phenocrysts of the same or different minerals, which occur in clusters. This view shows a particular cluster of crystals.
Pyroclastic texture refers to a sample comprised of fragments from volcanic activity. This sample contains numerous types of fragments.
Microphenocrysts are small crystals that are still larger than the groundmass. They are visible in the fine-grained matrix in this sample.
Microlites are tiny needle-like crystals, which have some microscopically detectable properties. They are the tiny needle-like crystals in this sample.
Trachytic texture consists of microlites that have been aligned due to the flow of lava.
Creator: 4518
Type: Igneous Rock
Mediator: Tamara Carley

Media: https://exhibits.lafayette.edu/geology/files/original/16f0647ffaf3b0e1301e21446c439dff.png; https://exhibits.lafayette.edu/geology/files/original/0b171baea26ed310d5c4b2305e04f5bc.png; https://exhibits.lafayette.edu/geology/files/original/48f92819b767cb207700bad6541a903f.jpg; https://exhibits.lafayette.edu/geology/files/original/8f48c65f5ae3ac69270c0860d3335030.jpg; https://exhibits.lafayette.edu/geology/files/original/a1aba251fc7c673d2d03728db2fd0e25.jpg

Janna's Test Site