View
80
Download
1
Category
Tags:
Preview:
Citation preview
Extrusive: Rocks formed on or near Earth’s surface Formed from lava Cool very rapidly Have small or no crystals
Felsic: Light or red in color Usually Lower
density High content of
aluminum
Mafic: Dark or green in color Usually Higher
Density High content of iron
or magnesium
COMPOSITION Felsic Intermediate Mafic
Lighter---------------------------Color----------------------------Darker Lower---------------------------Density--------------------------Higher
Intrusive Course
Grained Granite Diorite Gabbro
Extr
usi
ve Fine
Grained Rhyolite Andesite Basalt
Vesicular Pumice Scoria
Glassy Obsidian
• Definition:
– Small, solid pieces of material that come from rocks or living things like leaves, shells, etc.
Clastic Formed from various rock fragments Deposited by water, wind, glaciers Classified by grain size and shape Formed from Cementation or Compaction
Grain Size and Shape
Texture Grain Size Composition Comments Rock Name
Inorganic Land-Derived
Clastic
Pebbles, cobbles, and/or boulders
embedded in sand, silt and/or clay
Mostly quartz, feldspar, and clay
minerals; may contain fragments of
other rocks and minerals
Rounded fragments Conglomerate
Angular fragments Breccia
Sand (0.2 to 0.006 cm) Fine to course grained Sandstone
Silt (0.006 to 0.0004 cm) Very fine grained Siltstone
Clay (less than 0.0004 cm)
Compact, cannot see individual grains Shale
Chemical Formed when minerals dissolved in water crystalize
Think back to salt crystal lab
Crystalline(Chemical)
Fine-grained; crystals from
chemical precipitates and
evaporates
Halite
Softer than a fingernail, will not
react with acid, salt Rock Salt
Gypsum
Softer than a fingernail, will not
react with acid Rock Gypsum
CalciteCarbonate: will react
with acid Limestone
Organic Sedimentary Rock Forms where the remains of plants & animals are
deposited
Bioclastic(Organic)
Fine to course Calcite
Made of shells, will react with
acid Coquina
Fine-grained Carbon
Dark in color; made from plant
remains Coal
The term "metamorphic" means "to change form.“
These rocks have been put under high pressure and temperatures
They are not melted in this process, instead new minerals and physical make up change
There are two types of metamorphic rocks.
Each is classified according to its composition and texture. Foliated Nonfoliated.
FOLIATED metamorphic rocks are those in which the minerals have been flattened and pushed into layers
Examples of foliated rocks are slate, and gneiss.
NON-FOLIATED metamorphic rocks do not display layers. Rather, they are massive structures with no obvious banding.
The mineral grains grow and rearrange, but they don’t form layers.
A good example of non-foliated rock is quartzite or Marble
Metamorphism can occur in different degrees
The crystals can rearrange themselves without being melted
A metamorphic rock can go through metamorphism
Recommended