The Rock Cycle and rocks

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The Rock CycleCh 10 : 

The Rock CycleCh 10

Rocks and the Rock Cycle : 

Rocks and the Rock Cycle Magma is the parent of all rocks Three Major types Igneous “from fire” Sedimentary Metamorphic “Changed Form”

Slide 3: 

The Rock Cycle Series of processes in which rock changes from one type to another and back again.

Slide 6: 

Igneous Rocks Forms as Magma cools

- Igneous Rock Structures Below crust is Intrusive Intrusions- underground rock masses Batholiths over 100 square kilometers

Slide 8: 

Stock under 100 Km2 Laccolith-domed lake of rock, forces up small mountain ranges

Slide 9: 

Sill layer of rock formed between other layers Dikes- magma forcing it self across layers

Slide 10: 

Extrusions Above Crust is Extrusive Volcanic neck-lava remains from interior of volcano Lava plateau-lava flows out of cracks and covers land

Texture of igneous rock Slow cooling allows large (course) crystals to form Extrusive rock will have very small crystals

PorphyryPorphyry is a mix of large and small crystals : 

PorphyryPorphyry is a mix of large and small crystals

Rapid cooling may result in a glassy appearance obsidian, or may trap gas bubbles, pumice

Obsidian : 

Obsidian

Three Families of Igneous Rock : 

Three Families of Igneous Rock Granite light colored or felsic (silica) orthoclase feldspar, quartz, hornblende, and mica

Granite : 

Granite

Slide 18: 

Diorite medium colored, plagioclase feldspar, hornblende, augite and biotite. Little quartz

Slide 20: 

Basalt dark or mafic (Iron) plagioclase feldspar, and augite

Basalt : 

Basalt

Slide 22: 

Sedimentary Rocks Sedimentary rocks are formed when sediments undergo compaction (pressure) and cementation (glue)

Slide 23: 

3 types Clastic, Chemical, Organic Clastic- sediments (small pieces) are carried away by wind, water or ice and left as deposits These deposits then undergo cementation and compaction

Slide 24: 

Chemical- rocks form from minerals that have been dissolved in water Organic- rocks are the remains of living things

Slide 25: 

Clastics Clastics are identified by the size of their sediment Conglomerate- rounded. pebble size Breccia- angular pebble size Sandstone- sand sized particles Shale- clay particles

Slide 26: 

Conglomerate- rounded. pebble size

Conglomerate : 

Conglomerate

Slide 28: 

Breccia- angular pebble size

Breccia : 

Breccia

Slide 30: 

Sandstone- sand sized particles

Sandstone : 

Sandstone

Slide 32: 

Shale- clay particles

Shale : 

Shale

Slide 34: 

Chemical Some minerals precipitate due to a change in temperature, limestone Evaporates-left behind when water evaporates gypsum, halites

Limestone : 

Limestone

Rock salt and Gypsum : 

Rock salt and Gypsum

Slide 37: 

Organic Coal-formed from plants being buried then compacted Organic limestone-shells from clams, coral, oysters and plankton form limestone

Coal : 

Coal

Organic Limestone : 

Organic Limestone

Slide 40: 

Features Stratification-layer representing conditions when formed. cross-bedding Ripple marks and mud cracks Fossils Concretions precipitated minerals build up around existing rocks

Concretion : 

Concretion

Slide 42: 

Metamorphic rocks Rock may change because of exposure to heat and pressure, or have minerals dissolved or added Two types metamorphism Contact (direct) Regional (Barrovian)

Slide 44: 

Classification Foliation metamorphic rock has visible stripes Can be formed when crystals are pushed into parallel bands or minerals of different densities separate into bands

Schist : 

Schist

Slide 46: 

Banding Minerals form into district lines, Requires more heat and pressure than foliation Both take flat minerals like mica and force them into bands

Gneiss : 

Gneiss

Slide 48: 

Example of formation Slate, schist and gneiss Slate comes from shale More heat and pressure turn slate in schist Schist transforms into gneiss

Slide 49: 

Unfoliated Have no bands Formed from rocks with one mineral Quartzite formed from sandstone Marble formed from limestone

Slate : 

Slate

Quartzite : 

Quartzite

Marble : 

Marble

Images from about.geology.com : 

Images from about.geology.com