Earth Science

EARTH SCIENCE

BRANCHES OF EARTH SCIENCE

1. Geology - study of the solid matter that makes up the earth, its origin, composition, structure and

history. it is divided into several branches:

a) Mineralogy - study of minerals

b) Petrology - rocks

c) Stratigraphy - deposition of successive beds of sedimentary rocks

d) Palaeontology - fossils

e) Tectonics - deformation and movement of earth's crust

f) Geophysics - using physics to study earth's surface, interior and atmosphere

g) Geochemistry - science of chemistry as it applied to geology

2. Meteorology - scientific observation and study of the atmosphere so that weather can accurately

forecast

3. Oceanography - study of water movements-currents, waves and tides

4. Astronomy - study of physical things beyond the earth

FOUR SPHERES OF THE EARTH

STRUCTURE OF THE EARTH

The Earth consists of four concentric layers: inner core, outer core, mantle and crust. The crust

is made up of tectonic plates, which are in constant motion. Earthquakes and volcanoes are most

likely to occur at plate boundaries.

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The inner core is in the centre and is the hottest part of the Earth. It is solid and made up of

iron and nickel with temperatures

of up to 5,500°C. With its

immense heat energy, the inner

core is like the engine room of

the Earth.

2

The outer core is the layer

surrounding the inner core. It is a

liquid layer, also made up of iron

and nickel. It is still extremely hot,

with temperatures similar to the

inner core.

3

The mantle is the widest section

of the Earth. It has a thickness of approximately 2,900 km. The mantle is made up of semimolten rock called magma. In the upper parts of the mantle the rock is hard, but lower down

the rock is soft and beginning to melt.

4

The crust is the outer layer of the earth. It is a thin layer between 0-60 km thick. The crust is

the solid rock layer upon which we live. There are two different types of crust: continental

crust, which carries land, and oceanic crust,...