6. ROCKS
•Petrology is the scientific
study of rocks. Rocks are
combined aggregation of
minerals. Petrologist
classified rocks based on how
they were formed. In
general, rocks are classified
as igneous, sedimentary, and
metamorphic rock.
7. Earth is a solid rock to a depth of 2,900 kilometers, where
mantle meets the liquid outer core. A rock is a naturally
occurring solid aggregate of one or more minerals. The
aggregate minerals forming the rocks are held together by
chemical bonds. Grains can be different in color, texture,
and sizes. Geologists then group rocks into three categories
based on how the rocks form: igneous sedimentary and
metamorphic rock. Petrology is the scientific study of rocks.
Petrologists classify rocks based on how they were formed.
8. THREE TYPES OF ROCKS
1. Igneous- formed from hardening
and crystallization of magma or
molten material that originates deep
within the earth.
9. Two types of igneous rock
A. Extrusive/Volcanic rock - forms when magma makes its
way to Earth’s surface as lava and then cools. The
crystals are very small (fine grained) since the cooling
process is fast.
B. Intrusive/Plutonic - It cools slowly beneath the Earth
surface and are created by magma. The intrusive igneous
rocks have very large crystals (coarse grained).
10.
11. 2. Sedimentary- rocks provide information
about surface conditions that existed in
the Earth’s past.
12. ● Particles of sand, shells, pebbles, and other
fragments of materials called sediments,
accumulate in layers and over long period of
time harden into rocks.
● Compaction-due to increase of pressure of
layered sediments it bind together to form the
sedimentary rocks.
13. Three types of sedimentary rocks
a. Clastic Sedimentary rock - formed from accumulation of
clasts: little pieces of broken rocks and shells. Examples:
conglomerate, breccia, sandstone, shale
b. Chemical - formed when dissolved minerals precipitate
from a solution.
Example: Halite - formed when a body of seawater becomes
closed off and evaporates.
c. Organic - rocks formed from the accumulation of animal
debris Example: Coal - composed of organic matter in the form
of plants fragments
14.
15. 3. Metamorphic - forms from pre-existing
rocks: either metamorphic, igneous,
sedimentary
Examples: Quartzite, marble, slate,
phyllite
17. 2 types of metamorphism
1.Regional-due to changes in pressure
and temperature over large region of
the crust
2. Contact-mainly by heat due to
contact with magma
20. PERFORMANCE TASK 2
ROCKS
TYPE OF ROCK: SEDIMENTARY
DESCRIPTION:
Limestone is a sedimentary rock composed
principally of calcium carbonate (calcite) or the
double carbonate of calcium and magnesium
(dolomite). It is commonly composed of tiny
fossils, shell fragments and other fossilized
debris. ... Limestone is usually gray, but it may
also be white, yellow or brown.
IMPORTANCE:
a building material, an essential component of
concrete (Portland cement), as aggregate for the
base of roads, as white pigment or filler in
products such as toothpaste or paints,
21. What do rocks and minerals have in
common?
•Minerals are pure compounds, like Silicon Dioxide
( quartz), Calcium Carbonate ( calcite), or
Sodium Chloride ( halite).
•Rocks, on the other hand may be a collection of
different minerals, or a mass of a single mineral.
•Granite is an example of a rock with many
different minerals in it (quartz, orthoclase, mica,
and others). Limestone is an example of a one-
mineral rock (calcite).
24. We are earthbound. The crust is the outer, solid layer of the earth. Rocks and
minerals are significant components of the earth's crust.
In order to understand how the science, composition, and processes of the
earth affect us personally, we study them. We also study the fundamentals of
physics, chemistry, geometry, and other subjects as they relate to earth science
and how they affect our daily lives.
In the process described above, we learned about rocks and minerals, which are
used in many aspects of day-to-day life, including the management of health
and construction of homes, offices, buildings, and other structures
28. ROCK CYCLE
It is a series of processes that
create and transform the types
of rocks in Earth’s crust.
29. Exogenic Processes
The earth’s surface is composed of water and landmasses. The
solid portion is made out of rocks and minerals that could
experience changes either physically or chemically. The
weathered materials are transported by different agents from
one place to another and will settle down in a particular area.
These progressions that happen are achieved by forms called
exogenic processes. It includes weathering, erosion, and
deposition.
30. Weathering
•is the process of disintegration
(PHYSICAL) and decomposition
(CHEMICAL) of rocks.
•Weathering is a process of breaking
down rocks into small particles such as
sand, clay, gravel and other fragments.
31. 2 TYPES OF WEATHERING
Mechanical
Weathering (Physical
Weathering)- is the
breakdown of rocks
into pieces without
any change in its
composition.
Chemical Weathering-
there are changes in the
composition of rocks due
to the chemical reactions
32. Mechanical Weathering (Physical Weathering)
Factors Description
Pressure Due to tectonic forces, granite may
rise to form mountain range. After
the granite ascends and cools, the
overlying rocks and sediments may
erode. At the point when the
pressure diminishes, the rock
expands, cools, and became brittle
and fractured.
Roots of trees or other plants growing into cracks
in rocks may put pressure on the surrounding
rock, eventually breaking rocks apart as the roots
grow.
33. Mechanical Weathering (Physical Weathering)
Factors Description
Temperature Rocks expand and are fractured
when expose to high temperature.
However, if the temperature drops
to 0°C (freezing point of water), it
also expands and causes fracture.
Changes in temperature cause rock to expand
(with heat) and contract (with cold). As this happens
over and over again, the structure of the rock
weakens. Over time, it crumbles.
34. Examples of frost wedging
include boulders and mountains in
cold climates with large cracks in
them.
Mechanical Weathering (Physical Weathering)
Factors Description
Frost
Wedging
Generally, rocks have fracture in its
surface and when water accumulates
in the crack and at that point freezes,
the ice expands and breaks the rock
apart.
35. Mechanical Weathering (Physical Weathering)
Factors Description
Abrasion
The breakdown of rocks is caused by
impact and friction. This primarily
occurs during collision of rocks, sand,
and silt due to current or waves along
a stream or seashore causing sharp
edges and corners to wear off and
become rounded.
36. Examples of frost wedging
include boulders and mountains in
cold climates with large cracks in
them.
Mechanical Weathering (Physical Weathering)
Factors Description
Organic
Activity
The roots grow causing penetration
into the crack, expand, and in the long
run, break the rock.
37. Examples of frost wedging
include boulders and mountains in
cold climates with large cracks in
them.
Mechanical Weathering (Physical Weathering)
Factors Description
Human
Activities
Activities such as digging, quarrying,
denuding forests and cultivating land
contribute to physical weathering.
38. Mechanical Weathering (Physical Weathering)
Factors Description
Burrowing
Animals
Animals like rats, rabbits and squirrels
excavate into the ground to create a
space for habitation.
39. Chemical Weathering (there are changes in the
composition of rocks due to the chemical reactions )
Factors Description
Dissolution
It occurs in specific minerals which
are dissolved in water. Examples of
these minerals are Halite (NaCl)
and Calcite (CaCO3). The
formation of stalactites and s
40. Chemical Weathering (there are changes in the
composition of rocks due to the chemical reactions )
Factors Description
Hydrolysis
Rock-forming minerals like
amphibole, pyroxene, and feldspar
react with water and form
different kinds of clay minerals.
41.
42. Chemical Weathering (there are changes in the
composition of rocks due to the chemical reactions )
Factors Description
Oxidation
It is the response of oxygen with
minerals. If the iron oxidizes, the
mineral in rocks decomposes.
Rusting is an example of this
chemical reaction.
43. Erosion
is the separation and removal of weathered rocks
due to different agents like water, wind, and
glacier that causes transportation of the material
to where they are deposited. Plants, animals, and
humans play an important role in the erosional
process.
