GEOL 1313 Lecture 1: GEOLOGY VOCAB
Document Summary
Molten rock- originates in the mantle and crust as a result of partial melting of solid rock. Pyroclastic debris volcanic eruptions may produce pyroclastic debris such as ash and cinders. Lava flows volcanic eruptions may produce extensive lava flows. Extrusive (volcanic igneous) rocks- igneous rocks that form when lava turns into solid, when the rock reaches the surface. Intrusive (plutonic igneous) rocks- most magma never reaches the surface, instead it crystalizes at the depth of the surface. Fine-grained texture- igneous rocks that form at the surface, or a small mass within upper crust. (grains are naked to the eye) Vesicular texture- fine grained rocks contain voids left by gas bubbles. Course-grained texture- large masses of magma solidify at depth. (identified by naked eye) Glassy texture- rapid cooling of lava may generate a glassy texture. Pumice- mass if fine shards if intertwined glass. (extrusive) Porphyritic texture- large crystals embedded in a matrix of smaller crystals.
