Chapter 3 Rocks

3.1 The Rock Cycle Rocks  Rocks are any solid mass of mineral or mineral-like matter occurring naturally as a part of our planet.  Types of Rocks Igneous Sedimentary Metamorphic

The Rock Cycle Interactions between water, air, land, and living things can cause rocks to change from one type to another

Weathering and Erosion Weathering  is the breaking down of rocks, soils and minerals as well as artificial materials through contact with the Earth's atmosphere, biota and waters. Erosion is the movement, transportation, and deposition of soil and rock by wind, water, and gravity to other locations.

Igneous Rocks formed by the crystallization (hardening) of molten magma or lava. Magma is molten material deep beneath the Earth’s surface Lava is molten material above the surface Igneous Rocks

3.2 Igneous Rocks Formation of Igneous Rocks 1. Intrusive igneous rocks are formed when magma hardens beneath Earth’s surface. 2. Extrusive igneous rocks are formed when lava hardens (above the Earth’s surface).

Classification of Igneous Rock Texture Coarse-grained texture is caused by slow cooling resulting in larger crystals. Fine-grained texture is caused by rapid cooling resulting in smaller, interconnected mineral grains. Glassy texture is caused by very rapid cooling. Composition What minerals the rock is made of, based on the proportions of light and dark minerals in the rock.

Granite Rhyolite Obsidian Basalt

Classification of Igneous Rocks

3.3 Sedimentary Rocks What are Sedimentary Rocks? Sedimentary Rocks • Rocks made from pieces of other rocks

3 Types of Sedimentary Rock Clastic – composed of weathered bits of rocks and minerals Classified by particle size Ex: Shale, Sandstone, Conglomerate

The Wave, Page, AZ

Grand Canyon, Arizona

3 Types of Sedimentary Rock Chemical – When minerals dissolve out of water Ex: limestone (caves), rock salt Carlsbad Caverns, NM Stalactites Stalagmites

3 Types of Sedimentary Rock Organic – Formed by fossils or organic matter within the rock layers coal

Classification of Sedimentary Rocks

3.4 Metamorphic Rocks Formation of Metamorphic Rocks  Metamorphism means “to change form.”  Igneous and sedimentary rocks change at increased temperatures and pressures deep within the Earth or during mountain building Metamorphic Rocks

3.4 Metamorphic Rocks Agents of Metamorphism  Heat  Pressure Provides the energy needed to drive chemical reactions  Pressure Causes a more compact rock with greater density  Hydrothermal Solutions Hot water-based solutions escaping from magma Dissolves original minerals and then deposits new ones

Origin of Pressure in Metamorphism

3.4 Metamorphic Rocks Classification of Metamorphic Rocks  Two main categories 1. Foliated Metamorphic Rock Has a banded or layered appearance If the pressure applied to the rock is unequal, then a foliated rock will form. 2. Nonfoliated Metamorphic Rock Does not have a banded texture Gneiss Marble

Classification of Metamorphic Rocks