Earth and Space PSSA Workbook Series Free Powerpoint Templates

Physical Chemical Erosion Tearing Down the Earth Weathering Sediment Physical Chemical Erosion Changes appearance Reacting with H2O, O2, & acid Moving sediment Water gets into cracks Makes new minerals Carving land Wind acts like sandpaper Feldspar + Acid = Clay Slow or Fast Tree roots dig into rock Rocks are pitted Earthquakes & Nat. Disasters

Physical weathering includes the physical disintegration of rock material without making any change in its chemical composition.

Definition: Chemical weathering (also known as decomposition or decay) is the breakdown of rock (weathering) by chemical mechanisms, the most important ones being carbonation, hydration, hydrolysis, oxidation, and ion exchange in solution. Chemical weathering changes the composition of the rock material toward surface minerals, such as clays. It attacks minerals that are relatively unstable in surface conditions, such as the primary minerals of igneous rocks like basalt, granite or peridotite.

Building up the Earth Deposition or Sedimentation A deposit of material that builds up the earth Results from erosion that gathers and layers Results from molten rock or lava What comes down will build up.

Types of Rocks Sedimentary Tells about past organisms Igneous Tells about ancient volcanic eruptions Metamorphic Tells about mountain formation

Sedimentary Formed by deposition Creating horizontal layers Layer upon layer builds some pressure which cements lower layers together. Examples: sandstone, shale, limestone, coal(bits of organic materials), conglomerates(larger bits of sediments)

Sedimentary Sedimentary rocks make up about three-quarters of the rocks at the Earth’s surface. They form at the surface in environments such as beaches, rivers, the ocean, and anywhere that sand, mud, and other types of sediment collect. Sedimentary rocks preserve a record of the environments that existed when they formed. By looking at sedimentary rocks of different ages, scientists can figure out how climate and environments have changed through Earth’s history. Fossils of ancient living things are preserved in sedimentary rocks too. Many sedimentary rocks are made from the broken bits of other rocks. These are called clastic sedimentary rocks. The broken bits of rocks are called sediment. Sediment is the sand you find at the beach, the mud in a lake bottom, the pebbles in a river, and even the dust on furniture. The sediment may, in time, form a rock if the little pieces become cemented together. There are other types of sedimentary rocks whose particles do not come from broken rock fragments. Chemical sedimentary rocks are made of mineral crystals such as halite and gypsum formed by chemical processes. The sediment particles of organic sedimentary rocks are the remains of living things such as clamshells, plankton skeletons, dinosaur bones, and plants.

Various Sedimentary Sandstone Shale Limestone

Making sandstone

Igneous Formed by molten rock cooling and hardening Magma is molten rock underground Lava is molten rock above ground Crystals usually form Quick cooling = small crystals Slow cooling = larger crystals Examples: Granite, Basalt, obsidian, pumice

More on Igneous Igneous rocks form when molten rock cools and becomes solid. Molten rock is called magma when it is below the Earth’s surface and lava when it is above. Igneous rocks are divided into two groups, based on where the rock forms. Igneous rocks that form below the Earth’s surface are called intrusive igneous rocks (or plutonic). They form when magma enters an underground chamber, cools very slowly, and forms rocks full of large crystals. Igneous rocks that form above the Earth’s surface are called extrusive igneous rocks. These rocks, also called volcanic rocks, form when lava cools quickly at or above the Earth’s surface.

Various Igneous Granite Basalt Obsidian

Metamorphic Forms when heat and pressure change the chemical the composition of the material. New minerals and/or crystals form In PA, a lot formed when the Appalachian Mts. formed Examples: slate, quartzite, marble, gneiss

More on metamorphic Rocks metamorphose when they are in a place that is very hot and pressure is high. You can find such a place where Earth's tectonic plates are coming together. There, the colliding plates squish rocks, and hot pools of magma heat them deep underground. Some rocks only change a little, while others change a lot. When a rock is metamorphosed, its mineral crystals change. Usually, the same chemical ingredients are used to form new crystals during metamorphism. Sometimes new types of minerals grow that weren't in the rock before. Often, flat minerals like mica become lined up perpendicular (at a right angle) to the direction of pressure. When minerals within a metamorphic rock are organized this way, it is called foliation. Some metamorphic rocks are foliated and others are non-foliated.

Various Metamorphic Slate Quartzite Gneiss

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