Download Sedimentary Rocks

Sedimentary Rocks
• form from pieces of other, existing rocks or
pieces of once living things called
sediments
• represent only 5% of the volume of Earth’s
crust
• lithification is the process that converts
sediments into rock
• Weathering → Erosion → Deposition →
Compaction → Cementation
Sedimentary rocks form a thin
layer over 75% of Earth’s
surface.
Why?
Why?
Weathering ONLY occurs on the surface!
Lithification
Cementation
• the last step in the lithification process
• mineral crystals “glue” sediments together
and give the rock its color
Size of Sediment = Type of Rock
Clastic Sedimentary
• Made from pieces of
other rock
• Conglomerate (top)
has rounded
sediment
• Breccia (bottom) has
more angular
sediment
Clastic Sedimentary
• Sandstone (above) is made
from grain-sized sediment
• Shale (top right) and Mudstone
(bottom right) are made from
clay and silt sized sediment
Organic Sedimentary
• made from remains
of plants and
animals
• Chalk (top) is made
from grains of tiny
sea creatures.
• Limestone (middle)
is made from coral
reefs and other
marine material.
• Coal (bottom) is
made from
decayed plant
material.
Chemical Sedimentary
• form when minerals
come out of solution
(precipitate) or are left
behind after evaporation
• Halite (top) is rock salt
created from salt water.
• Limestone (middle) is
made from precipitated
minerals.
• Geodes (bottom) are
made from minerals that
crystallize inside a
hollow space.
Unique Features
Stratification – visible bands
that result from layers of
different sediment being
deposited one atop another.
The oldest layers are
always at the bottom. This is
the Law of Superposition.
Unique Features
Whelk shells were dug up and exposed
during quarrying operations in Florida.
Nearly all are “right-handed” species,
opposite of today’s whelks.
In 1793, canal digger William Smith
discovered that by tracing fossils he
could follow layers of rocks across
England. He spent 22 years creating a
hand-painted map. But instead of being
honored, he ended up in debtors'
prison, the victim of plagiarism, and
was homeless for 10 years. In 1831,
this quiet genius -- now known as the
father of modern geology -- received
the Geological Society of London's
highest award and King William IV
offered him a lifetime pension.
Gemstone Formation
Gemstones
associated with
sedimentary rock
include jasper,
malachite, opal and
zircon.
Petrified Forest National Park, Nevada
Petrified Wood, Nevada
Stonehenge, England
(sandstone)
Arches National Park, Utah
(banded sandstone)
The elephant rock formation in Valley of Fire State Park in
Nevada is natural sandstone
12 Apostles in Australia
Smithsonian Institution, Washington, DC
(sandstone)
White Cliffs of Dover, England
Guadalupe Mountain, Texas
(organic limestone)
Bonneville Salt Flats, Utah
• The
Badwater
salt flats in
California
is the
lowest
point in
the U.S. at
282 feet
below sea
level.
Caves
(chemical limestone)
The Blue Grotto, Capri, Italy
The Blue Grotto
The blue coloration is due to light reflection off of the
limestone formations below the water of the grotto.
Irish Peat Bogs
Irish Cottages were/are heated with peat.
Peat Bricks
Striped Icebergs!
Is NJ’s marl a rock?