Presentation on theme: "Unit #2: Rocks, Minerals, and Resources. Rock - a naturally formed solid piece of the Earth’s crust composed of a mixture of minerals All rocks have."— Presentation transcript:
Unit #2: Rocks, Minerals, and Resources
Rock - a naturally formed solid piece of the Earth’s crust composed of a mixture of minerals All rocks have minerals /The-Rock-Cyclehttp://www.schooltube.com/video/503ca205aae459f4 7494/The-Rock-Cycle
Rocks that contain 1 mineral are called monomineralic. Rocks that contain more than 1 mineral are called polymineralic.
Rock Types Igneous Sedimentary Metamorphic
Rock Classification Rock are classified based upon how they form. Igneous rocks form from the cooling and solidification of molten rock.
Sedimentary rocks form from fragments of other rocks, chemical precipitates, or organic remains. Metamorphic rocks form from other rocks that undergo intense heat and pressure but not melting.
Types of Molten Rock Lava - liquid rock at the Earth’s surface Magma - liquid rock beneath the Earth’s surface
Mt Etna, November 18, 2013
Types of Igneous Rock Intrusive or Plutonic - form from magma - have larger crystals and a coarse texture Extrusive or Volcanic - form from lava - have smaller crystals and a finer texture
Composition Mafic Dark color, high density Contains Magnesium(Mg) and Iron(Fe) bearing minerals Felsic Light color, low density Contains feldspar and silicate minerals High aluminum(Al) content
Vesicles Tiny holes created by gases escaping from molten lava while it is cooling and solidifying
Coarse Texture in Gabbro
Fine Texture in Basalt
Extrusive Igneous Rock
Do Now 1.What three factors are used to identify igneous rocks? 2.What processes cause the formations of the following rock types? (Igneous, Metamorphic, Sedimentary) 3.Where do sediments come from?
Types Of Sediments Clastic- Fragments of Other Rocks-Grain Size Evaporties- Sea Water evaplorates leaving behind sediments. (Salt) Precipitates- Chemical-Solutioning(ions) Biologic-Plankton, Diatoms Biologic- Terrestrial– Plants/Trees Marine- Shells, Coral, Stromatalites
Types of Sedimentary Rock Clastic or Fragmental - form from the fragments of other rocks (sediment)
Stream Deposition Cause of deposition- Velocity Decreases Sediment characteristics effecting deposition –Size – –Shape- –density
Size: Largest Particles Settle Fir st Shape: Roundest Particles Settle First Density: The most dense particles settle first.
Types of Sedimentary Rock Nonclastic - organic and chemical - form from organic remains (shells, etc.) or chemical precipitates
Types of Metamorphism Regional - heat and pressure are applied to a large area of rock in collision zones of the Earth’s tectonic plates Contact or Thermal - rock is “burned” due to heat from lava or magma
Types of Metamorphic Rock Foliated- have banded, striped, or layered minerals due to pressure applied during metamorphism Nonfoliated - do not have a banded, striped, or layered appearance
Foliation and Distorted Structure
Features in Igneous Rocks The faster the molten rock cools the smaller the crystal size in the resulting rock. Rock forming from lava have smaller crystals than rocks forming from magma
Some igneous rocks have a glassy texture due to quick cooling. Some igneous rocks have holes called vesicles formed by gases escaping from lava.
Features in Sedimentary Rocks Fossils tend to occur only in sedimentary rocks. Some sedimentary rocks have fragments of other rocks (sediment) within them.
Sedimentary rocks form in flat, horizontal layers called strata. Some sedimentary rocks form from evaporating sea water (evaporites).
Some other features in sedimentary rocks are : Cross Bedding Ripple Marks Mud Cracks Graded Bedding
Cross Bedding in Sandstone
Ripple Marks in Sand
Mud Cracks in Clay
Features in Metamorphic Rocks Some metamorphic rocks have a banded, striped, or layered appearance (foliation). Metamorphism can enlarge mineral grains or create new minerals.
Metamorphism can increase the density of a rock. Some metamorphic rocks have a distorted or twisted rock structure created by intense pressure. Metamorphism causes changes in rock through recrystallization.
Distribution of Rock Types on the Earth Sedimentary rocks tend to be found in a thin layers at the Earth’s surface. Igneous and Metamorphic rocks tend to form in mountain ranges.
The abundance of igneous and metamorphic rocks increase as you go deeper into the Earth.