Download - 5. Rock Cycle
Rock CycleRock CycleCVE 3205CVE 3205
Engineering GeologyEngineering GeologyWong Jee KhaiWong Jee Khai
The Rock CycleThe Rock Cycle• The nature and appearance of a rock is
strongly influenced by the minerals that compose it.
• A rock’s texture – size, shape, and or arrangement of its constituent minerals also has significant effect on its appearance.
The Rock CycleThe Rock Cycle• Rock is any naturally formed, nonliving,
firm and coherent aggregate of mineral matter that constitutes part of a planet.
The Rock CycleThe Rock CycleThe three rock families:1. Igneous rock2. Sedimentary rock3. Metamorphic rock
Igneous rockIgneous rock• Created through the cooling and
solidification of magma• Ignis = fire
Sedimentary rockSedimentary rock• Formed from deposits of sediment• Lithification = conversion into rock
Metamorphic rockMetamorphic rock• Formed by the effects of pressure and
heat on existing rocks
The Rock CycleThe Rock Cycle• The rock cycle describes all the processes by
which rock is:• Formed.• Transported.• Decomposed.• Reformed.• Active volcanoes produce igneous rocks.• Mountain ranges rise as a result of plate
tectonics.• Weathering and erosion change the surface of
the solid Earth.
The Rock CycleThe Rock Cycle• The sediment is buried and compacted,
eventually becoming sedimentary rock.• Deeper burial turns sedimentary rock into
metamorphic rock.• Even deeper burial may cause some of
the metamorphic rock to melt, forming magma from which new igneous rock will form.
The Rock CycleThe Rock CycleEnergy that drives earth’s rock cycle;• Heat from earth’s interior (igneous and
metamorphic rocks)• Sun (sedimentary rocks)
The Tectonic CycleThe Tectonic Cycle• Tectonics is the study of the movement
and deformation of the lithosphere.• When magma rises from deep in the
mantle, it forms new oceanic crust at midocean ridges.
The Tectonic CycleThe Tectonic Cycle• The lifetime of oceanic crust is shorter
than the lifetime of continental crust.• The most ancient oceanic crust of the
ocean basins is only about 180 million years old, and the average age of all oceanic crust is about 70 million years old.
The Tectonic CycleThe Tectonic Cycle• When all oceanic crust sinks back into the
mantle, it carries some water with it.• The water is driven off during volcanic
eruptions.• Some constituents in the hot rock
(calcium, magnesium) are the same as those of seawater.
Geologic Time ScaleGeologic Time Scale• During the nineteenth century, before the
discovery of radioactivity, geologic time scale was developed using principles of relative dating which places the events in proper sequence or order without knowing their age in years.
Geologic Time ScaleGeologic Time Scale• This is done by applying the law of
superposition which states that in layers of sedimentary rocks or lava flows, the youngest layer is on top and the oldest is on the bottom.
Geologic Time ScaleGeologic Time Scale• Fossils are the basis for the principle of
fossil succession, which states that fossil organisms succeed one another in a definite and determinable order, and therefore any time period can be recognized by its fossil from countless rock layers around the world.