Init <<3/4/2008 by Daniel R. Barnes WARNING: Many of the images in this presentation were taken without permission from other people’s web sites. Do not copy or distribute this presentation. Its very existence may be illegal.

What do you call melted rock that’s still underground? magma

What must happen to magma for it to turn into rock? magma cooling

What kind of rock does magma turn into when it cools enough to crystallize? magma cooling igneous rock

Igneous Rock Igneous rock forms when liquid rock cools and solidifies. If igneous rock forms underground from magma, it will cool slowly, allowing large crystals to form. Igneous rock that forms undergound from magma is called “intrusive” igneous rock. Granite, with its spotty, coarse texture, is a good example of intrustive igneous rock.

Igneous Rock Igneous rock forms when liquid rock cools and solidifies. If igneous rock forms on the surface of the earth, from lava, it cools relatively quickly, and this doesn’t give large crystals a chance to form. Lava rock is called “extrusive” igneous rock. Basalt is a good example of extrusive igneous rock. It’s what Hawaiian volcanoes are made of. Furthermore, lava gives off gas easily because of the low pressure here at the earth’s surface, If this happens during cooling, the resulting lava rock can have a bubbly, “vessicular”, swiss cheese-like structure.

What kind of rock of rock is this? magma cooling igneous rock granite

What can cause the crystals in igneous rock to re-crystallize? magma cooling igneous rock heat &/or pressure

What kind of rock is produced when heat &/or pressure re-crystallize the rock? magma cooling igneous rock metamorphic rock heat &/or pressure

Metamorphic Rock “Metamorphic” rock has gone through metamorphosis, a great change. You may be more familiar with biological examples metamorphosis than you are with geological examples. For instance, you know that a caterpillar metamorphoses into a butterfly.

Metamorphic Rock “Metamorphic” rock has gone through metamorphosis, a great change. You may be more familiar with biological examples metamorphosis than you are with geological examples. You also know that a tadpole metamorphoses into a frog.

Metamorphic Rock Metamorphic rock forms when pre-existing rock is subjected to heat and/or pressure. During metamorphosis, heat and pressure cause atoms in mineral crystals to pop out of place and pop back in somewhere else. If there is pressure directed in one direction, crystals can get smashed, producing a metamorphic rock with “foliated” system of layers. Foliated layers in metamorphic rock are sometimes quite wavy, unlike the layers in sedimentary rock, which are often perfectly flat and straight.

Metamorphic Rock Heat and pressure can turn the igneous rock granite into the metamorphic rock gneiss.

magma cooling igneous rock metamorphic rock heat &/or pressure gneiss What kind of rock is this?

What can turn metamorphic rock back into magma? magma cooling igneous rock metamorphic rock extreme heat heat &/or pressure

What can turn any kind of rock into little bits of dirt, sand, or gravel? magma cooling igneous rock metamorphic rock extreme heat weathering heat &/or pressure

What do you call the tiny bits of rock produced by weathering? magma cooling igneous rock metamorphic rock extreme heat weathering sediment heat &/or pressure

What do you call it when sediment moves from place to place? magma cooling igneous rock metamorphic rock extreme heat weathering sediment erosion heat &/or pressure

What do you call it when sediment settles down and stops moving? magma cooling igneous rock metamorphic rock extreme heat weathering sediment erosion deposition heat &/or pressure

What two processes turn sediment into rock? magma cooling igneous rock metamorphic rock extreme heat weathering sediment erosion deposition compaction & cementaion heat &/or pressure

What do compaction and cementation turn sediment into? magma cooling igneous rock metamorphic rock extreme heat weathering sediment erosion deposition compaction & cementaion sedimentary rock heat &/or pressure

Sedimentary Rock Sedimentary rock forms from bits of rock (sediments) and/or minerals that crystallize from solutions. Shale is the most common form of sedimentary rock. It forms from millions of tiny clay particles that accumulate slowly over long periods of time to form layers, year after year, typically at the bottom of lakes, seas, or oceans. Limestone is made of calcium carbonate, which could come from seashells, microplankton shells, or from ions dissolved in seawater that have crystallized.

Sedimentary Rock Sedimentary rock forms from bits of rock (sediments) and/or minerals that crystallize from solutions. Limestone is made of calcium carbonate, which could come from seashells, microplankton shells, or from ions dissolved in seawater that have crystallized. Limestone was used in large quantities to build the pyramids of ancient Egypt.

Sedimentary Rock Sedimentary rock forms from bits of rock (sediments) and/or minerals that crystallize from solutions. Sedimentary rock layers are very obvious in the cliff walls of the Grand Canyon. These layers tell a story. The old layers are at the bottom, the younger layers on top. younger rocks & fossils older rocks & fossils