Chapter 3.1 Lecture 8/28/16

The Rock Cycle The product of the external and internal forces on Earth (Tectonic Forces) It takes millions of years Rocks move from deep to shallow (the core to crust) From high to low temps (lava lamp) Magma solidifies on the surface (igneous)>Weathered/Eroded (sedimentary)> Get forced down and subject to immense heat and pressure (metamorphic).

A Plate Tectonic Example A Convergent Boundary

Igneous Rocks Solidified from Magma (Lava=Magma on Earth’s surface) Extrusive formed on the surface (Basalt) Click Here Intrusive formed underground (Granite) No-one has ever seen magma solidify into intrusive rock (takes too long)

Igneous Rocks (Extrusive vs. Intrusive) Extrusive Igneous rocks form FINE GRAINED (glassy) crystals Intrusive Igneous rocks form MUCH COARSER or larger crystals. Country Rock, Xenolliths, and Chill Zones

Igneous Rock Textures Fine Grained (Less than 1mm). Basalt, Andestine, Rhyolite. Plutonic Rocks (Pluto means underword). Coarse grained and formed well below the surface. Country rock: a geological term meaning the rock native to an area. The term is used to denote the usual strata of a region in relation to the rock which is being discussed or observed.

Igenous Rock Compostion Gabbro (Ferromagnesian (silicates that contain iron) and plagioclase feldspar) Rhyolite= Feldspars. All igneous rocks contain Silica (SiO2) from 45% to 75% of the total mass Mafic= Silica deficient…less than 50% (Basalt and Gabbro Silicic =65% Silica and 25%-35% Feldspar (Potassium and Sodium).

Intrusive Bodies Rock that intrudes into surrounding rock. Important feature of the Earth’s Crust Classified based on size, geometric shape, formed at depth or near the surface, Ship Rock: intrusive rock that formed from magma under a volcano. The country tock eroded away laying way to ship rock . Dike= Not parallel to country Rock Sill= Parallel to Country Rock