d

• A rock is a naturally occurring solid mixture of one or more minerals, or organic matter.

• Rocks are classified by how they are formed, their composition, and texture.

• Rocks change over time through the rock cycle.

What is rock?

What is rock cycle? Rock cycle is the continuous changing of rocks from one kind to another over long periods of time.

The process of rock cycleWeatheringErosion & TransportationDeposition of SedimentsBurial & CompactionDeformation & MetamorphismCrystallization of magmaUplift

Weathering• Weathering is the breakdown of rocks at the

Earth’s surface, by the action of rainwater, extremes of temperature. And biological activity.

• There are three types of weathering: Physical Chemical Biological

Erosion and TransportErosion is the process by which soil and rock particles are worn away and moved elsewhere by gravity, or by a moving transport agent- wind, water or ice.

Transport refers to the processes by which the sediment is moved along.

Wind

Water

Ice

Deposition of Sediments

• Deposition is the laying down of sediments carried by wind, water or ice.

Wind

Water Ice

Burial and Compaction

As layers are piled one upon another,the sediments beneath are buried, sometimes by hundreds of meters of sediment above.

Deformation & Metamorphism• The huge forces that move

continents stretch and squash parts of the Earth’s crust., generating earthquakes and building mountains.

• They cause rocks near the surface to be fracture and faulted.

• At greater depth, the heat and pressure involved can cause folding and/or metamorphism.

Deformation

Metamorphism

Crystallization of magma

When molten rock tends to work its way upward. If it reaches the surface, there will be volcanic eruption or lava flows. This quickly cooled magma forms either glassy or very fine-grained rocks.

Uplift

Uplift happens when the Earth’s crust is constantly moving, and mountain ranges are lifted up as continents collide, squashing, folding and faulting the rock layers that are caught up in the process.

Igneous rock

• Igneous rock begins as magma.• Magma can form: When rock is heated. When pressure is released. When rock changes composition.• Magma freezes between 700 °C and 1,250 °C• Magma is a mixture of many minerals.

Igneous rock

• Felsic: light colored rocks that are rich in elements such as aluminum, potassium, silicon, and sodium.

• Mafic: dark colored rocks that are rich in calcium, iron, and magnesium, poor in silicon

• Coarse-grained: takes longer to cool, giving mineral crystals more time to grow

• Fine-grained: cools quickly with little to no crystals

Igneous rockCoarse-Grained Fine-Grained

Felsic

Mafic

Igneous rock

• Intrusive Igneous Rocks: magma pushes into surrounding and the rock solidify below the Earth’s surface.

Extrusive Rocks: forms when magma erupts onto the Earth’s surface (lava), cools quickly with very small or no crystals formed and solidify on or above Earth's surface.

Sedimentary rockSedimentary rock is formed by erosion.Sediments are moved from one place to another.

Sediments are deposited in layers, with the older ones on the bottom.

The layers become compacted and cemented together.

There are three main types of sedimentary rocks:

• Clastic: your basic sedimentary rock. Clastic sedimentary rocks are accumulations of clasts: little pieces of broken up rock which have piled up and been "lithified" by compaction and cementation.

• Chemical: many of these form when standing water evaporates, leaving dissolved minerals behind.

• These are very common in arid lands, where seasonal "playa lakes" occur in closed depressions.

• Thick deposits of salt and gypsum can form due to repeated flooding and evaporation over long periods of time.

• Organic: any accumulation of sedimentary debris caused by organic processes.

• Many animals use calcium for shells, bones, and teeth.

• These bits of calcium can pile up on the seafloor and accumulate into a thick enough layer to form an "organic" sedimentary rock .

Metamorphic rock

• Meaning to change shape.

• Changes with temperature and pressure, but remains solid.

• Usually takes place deep in the Earth.

Formation of metamorphic rock

• Contact Metamorphism – heated by nearby magma.

• Increased temperature changes the composition of the rock, minerals are changed into new minerals.

• Regional Metamorphism – pressure builds up in rocks that is deep within the Earth.

• Large pieces of the Earth’s crust collide and the rock is deformed and chemically changed by heat and pressure.

References::

www. google.comwww.geolsoc.orgwww.Geology.comhttp://jersey.uoregon.edu/~mstrick/AskGeoMan/geoQuerry14.html

Prepared by:Irah P. Sanchez