Transcript 3.3 Sedimentary rocks form from earlier rocks

Classifying Rocks
 3 rock types
 Sedimentary
 Igneous
 Metamorphic
Sediment
Rock fragments, minerals,
or plant and animal remains
that settle out of water or air
Sedimentary Rocks
 “that which has settled”
 Formed from sediments
 Sediments=rocks exposed to weather that have been
broken down into very small pieces

Formation depends on weathering/erosion
 Sediments packed into layers
 Cement together over time
Sedimentary
Sediments change into Rock by
Pressure
Cemented together by
new minerals to form
rock
Coal
Sedimentary rock formed
from remains of plants,
bark roots, and other plant
material that is buried
and under pressure
Contains NO minerals
Conglomerate
Sedimentary rock with
pieces of shells, rocks,
minerals or other
products that are larger
than 2 mm cemented
together with minerals.
Limestone
Sedimentary rock made of
shells and skeletons of
ocean organisms.
Over time the individual
shells are no longer visible
and become limestone
Sedimentary Rock and Wind
Water movement: Larger
sediment drops before
smaller sediment
Wind Direction : Crossbeds, Ripples, Mud Cracks
Challenge
 Refer to book…
 What is the difference between compaction and
cementation?
 Compaction occurs when sediment is squeezed together by
the weight of other sediment above it, and cementation
occurs when sediment is cemented together by dissolved
minerals.
 How do chemical and biochemical sedimentary rocks
form?
 Chemical sedimentary rocks form when minerals crystallize
out of solution in water, and biochemical sedimentary rocks
form from the action of organisms in water.