The Rock Cycle Ch 10

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

Magma is the parent of all rocks

Three Major types

Igneous “from fire”

Sedimentary

Metamorphic “Changed Form”

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

The Rock Cycle

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

Igneous Rocks Forms as Magma cools

Igneous Rocks

Forms as Magma cools

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

- Igneous Rock Structures

Below crust is Intrusive

Intrusions- underground rock masses

Batholiths over 100 square kilometers

Stock under 100 Km 2 Laccolith -domed lake of rock, forces up small mountain ranges

Stock under 100 Km 2

Laccolith -domed lake of rock, forces up small mountain ranges

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

Sill layer of rock formed between other layers

Dikes - magma forcing it self across layers

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

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

Texture of igneous rock

Slow cooling allows large (course) crystals to form

Extrusive rock will have very small crystals

Porphyry Porphyry is a mix of large and small crystals

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

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

Obsidian

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

Granite light colored or felsic (silica) orthoclase feldspar, quartz, hornblende, and mica

Granite

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

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

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

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

Basalt

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

Sedimentary Rocks

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

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

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

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

Chemical - rocks form from minerals that have been dissolved in water

Organic - rocks are the remains of living things

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

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

Conglomerate- rounded. pebble size

Conglomerate- rounded. pebble size

Conglomerate

Breccia- angular pebble size

Breccia- angular pebble size

Breccia

Sandstone - sand sized particles

Sandstone - sand sized particles

Sandstone

Shale - clay particles

Shale - clay particles

Shale

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

Chemical

Some minerals precipitate due to a change in temperature, limestone

Evaporates -left behind when water evaporates gypsum, halites

Limestone

Rock salt and Gypsum

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

Organic

Coal -formed from plants being buried then compacted

Organic limestone -shells from clams, coral, oysters and plankton form limestone

Coal

Organic Limestone

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

Features

Stratification-layer representing conditions when formed. cross-bedding

Ripple marks and mud cracks

Fossils

Concretions precipitated minerals build up around existing rocks

Concretion

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)

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)

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

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

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

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

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

Example of formation

Slate, schist and gneiss

Slate comes from shale

More heat and pressure turn slate in schist

Schist transforms into gneiss

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

Unfoliated

Have no bands

Formed from rocks with one mineral

Quartzite formed from sandstone

Marble formed from limestone

Slate

Quartzite

Marble

Images from about.geology.com