Earth Processes: Part 1: Lithosphere (land) The student will be able to describe types of rocks and the processes involved in the rock cycle. The student will be able to explain the theory of plate tectonics and how it relates to the formation of volcanoes and earthquakes.

Geology = the study of the earth (lithosphere) Minerals – naturally occurring solid elements and compounds. FYI: minerals are to rocks as letters are to words. Minerals make up rocks! Letters make up words!! Rocks are usually mixtures of 2 or more minerals. Geology = the study of the earth Minerals – naturally occurring solid elements and compounds. Can be made up of all same thing or two different things. FYI: minerals are to rocks as letters are to words. Minerals make up rocks! Letters make up words!! Rocks are usually mixtures of 2 or more minerals.

Some minerals can form…. Three Main Groups of Rocks · Igneous rocks-form from extremely hot melted rock material-MAGMA (ex: granite) · Sedimentary rocks-made of mineral grains that become cemented together, under pressure, forming solid rock (ex: limestone) · Metamorphic rocks-formed by changes (extreme heat/pressure) in sedimentary or igneous rocks (ex: marble)

Sedimentary rock example: Sandstone Igneous rock example: Granite Metamorphic rock example: Marble

PROPERTIES OF ROCKS COLOR -this is the least beneficial property to use, especially all by itself. For example, if you have two white rocks…does that mean they are the same type of rock? STREAK-color of pulverized substance, usually tested on tile by trying to “write” with it.

LUSTER-quality and intensity of light reflected…how shinny or dull is it??? HARDNESS-ease or difficulty in which it can be scratched. Mohs’ Hardness Scale Scale from 1 - 10 that ranks how hard or soft a rock is… used as a reference to compare .

1 is the softest and 10 is the hardest

CRYSTAL FORM- definite geometric relationship foliated = distinct parallel layers/bands non-foliated = NO distinct layers CLEAVAGE-the ability of a mineral to break along preferred planes. (clean break) FRACTURE-the way a substance breaks where not controlled by cleavage (uneven break) DENSITY OR “HEAVINESS” HOW DOES IT REACT WITH CERTAIN CHEMICALS…ACID?? All these properties are used together to identify rocks…never use just one by itself

They can change from one type of rock to another. ROCK CYCLE - All rocks go through a cycle, constantly changing shape due to weathering, erosion, heat, pressure, hardening and cooling. They can change from one type of rock to another. (For example, a sedimentary rock will not always be a sedimentary rock.) Weathering-the breaking down of rocks by weather. There are two types of weathering: Physical weathering (rocks broken) Chemical weathering (composition changed) Erosion -the process by which Earth materials are moved from one place to another. Wind (rain, waves), water, gravity, ice, organisms

Plate Tectonics- plates of the earth move about on earth, carrying continents and ocean floor with them. PANGEA – all continents were once one entire land mass; one continent Due to Continental Drift /Sea Floor Spreading the continent was broken apart and drifted apart in ocean to where they are today.

There are three types of movements: Movements can occur between plates. These movements can cause earthquakes, mountains, volcanoes, and continental drift. Fault-zone of weakness in the crust, along which some movement of rock takes place. There are three types of movements: Divergent - plates moving away from each other (produces sea floor spreading) Convergent - plates moving towards each other (produces volcanoes and mountains) Transform - plates moving parallel to each other in opposite directions (produces earthquakes)

Sea Floor Spreading

Results from an earthquake….. Transform Plate Movement (side to side)  

San Andrea's Fault…What type of movement is this do you think?

Volcanoes-an opening in the crust through which magma from within Earth flows out as lava (formed from convergent plate movement) Magma = underground Lava = above ground Volcanoes contain a “Zone of weakness”. This zone is like a fault down under and when plates put pressure on it, they push up magma.(subduction zone)

Old remains of volcano conduit