2. At the end of this topic learners must be able to:
1. Classify rocks into igneous, sedimentary, and metamorphic
2. Identify the minerals important to society
3. Describe how ore minerals are found, mined, and processed for human use
3. ▪ Geology is the study of rocks and geologists are the people who study them!There
are many different types of geologists. Some of the common types are listed
below.
▪ Mineralogists study minerals.
▪ Petrologist study rocks.
▪ Structural geologist study how plate tectonics moves and squishes rocks.
▪ Paleontologists study Earth history and fossils.
▪ Stratigraphers study how layers of sedimentary rock form though geologic time.
▪ Geomorphologists study how the land surface is shaped by water, wind and ice.
Who studies rocks?
4. What is a geologist like?
Well, they are all very different. Click on the links below to get to
know some famous geologists.
Florence Bascom, a mineralogist and petrologist, led the way for
American women geologists over 100 years ago.
Charles Darwin was the first scientist to publish a comprehensive
theory of evolution in the19th century.
Stephen Jay Gould expanded Darwin's theory with his own concept
of punctuated equilibrium in the 20th century.
Friedrich Mohs, a mineralogist, developed a way to identify minerals
by their hardness.
Leonardo da Vinci did a little bit of everything! When he was not
painting the Mona Lisa, he was a scientist and discovered how
sedimentary rocks and fossils are formed.
A rock is a naturally occurring aggregate of minerals, and
certain non-mineral materials such as fossils and glass.
5. The Rocks Cycle
▪ Rocks are constantly being
transformed in a process called
rock cycle.
▪ gneous is derived from the latin
word ignis meaning “of fire”.
6. Sedimentary rocks form from material that has accumulated on
Earth’s surface in a process called deposition.
▪ The deposited material consists of the
products of weathering and erosion, and
other materials as well that are available
on Earth’s surface, such as organic
material.
▪ Sedimentary rocks, which were lithified
below the surface, only become exposed
at the surface by tectonic uplift and
erosion of the overlying material.
7. Metamorphic rocks form when a sedimentary or igneous rock is
exposed to high pressure, high temperature, or both, deep below
Earth’s surface.
▪ Metamorphism produces fundamental
changes in the mineralogy and texture of the
rock.
▪ the protolith which can either be an igneous
rock or a sedimentary rock
▪ Because all metamorphic rocks form from
below the surface, they must undergo
tectonic processes such as continental
collisions, which cause horizontal pressure
with friction and heat for them to become
exposed at the surface.
9. The classification of rocks is based on two criteria: texture
and composition
▪ Igneous Rocks
▪ Igneous rocks are crystalline solids which form directly
from the cooling of magma.
▪ This is an exothermic process (it loses heat) and
involves a phase change from the liquid to the solid
state.
▪ The earth is made of igneous rock – at least at the
surface where our planet is exposed to the coldness of
space.
▪ Igneous rocks are given names based upon two
things:
▪ composition (what they are made of) and
▪ texture (how big the crystals are)
10.
11. Sedimentary Rocks
•These rocks get their name from the Latin word
sedimentum which means settle down.
•These rocks are formed by the settling down of
sediments.
•Sediments are the smaller particles / fragments
that are formed by the breaking down of rocks
when they roll down, crack and hit each other.
•These sediments are transported by wind,
water etc.
•These sediments; when compressed and
hardened; form sedimentary rocks.
•Sandstone is an example of sedimentary rock.
It is made up of grains of sand.
•The sedimentary rocks may also contain fossils
of plants, animals and other micro – organisms
that once lived on them.
