Download Introduction to geology

General Geology
Dr. Masdouq Al-Taj
What is Earth Science
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All the sciences that collectively seek to
understand Earth and its neighbors in
space.
Includes geology, oceanography,
meteorology and astronomy.
The science of Geology
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Geology is the science that try an
understanding of the planet Earth
1. Physical geology - examines the materials
composing Earth and seeks to understand
the many processes that operate beneath
and upon its surface
2. Historical geology - seeks an
understanding of the origin of Earth and
its development through time
The Earth from the Space
A view of Earth
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Earth is a planet that is small and selfcontained
Earth’s four spheres
Hydrosphere
 Atmosphere
 Biosphere
 Solid Earth
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Hydrosphere
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Is a dynamic mass of water.
Having a cycle.
Oceans covers 71% of the Earth’s
surface, down to 3800 meters, and
accounts for about 97% of Earth’s
water… rest found as groundwater,
streams, lakes and glaciers.
Atmosphere
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90% of the atmosphere occurs within the
16km of the Earth’s surface.
For comparison, Earth’s mean radius =
6400km.
Essential for life, producing climate or
weather, protects earth from radiations and
intense heat, and shaping the Earth’s surface
(by weathering and erosion).
Atmosphere structure
Volumetric Percent of Dry clean Air (%)
Biosphere
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Includes all types of life on Earth.
Concentrated near the surface of Earth.
Extends from the bottom of oceans to
several km’s into the atmosphere.
Solid Earth (Geosphere)
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Not uniform.
Divided into:1. Core (very dense inner sphere).
2. Mantle (less dense).
3. Crust ( light and very thin).
Geosphere: The Solid part of the earth, and consists
of :a- Earth Crust. (oceanic crust and continent al crust).
* Oceanic crust (5-10 km, avg. 7Km) , mainly basaltic.
* Continental Crust (25-70Km, avg. 35 km) mainly granitic.
B-Moho discontinuity: high dense layer that is lies below the
crust.
C - Mantle (high density Rx) extends from the Moho to a depth
2900Km.
*Lithosphere :crust+ the upper most part of mantle.
*Asthenosphere: The upper part of the mantle (from the
Base of lithosphere to a depth 660Km). (include low velocity
zone+Transition zone).
D - Outer core. (Liquid) (2270 Km) thick
E - Inner Core. (Solid) (1216 Km) thick.
Earth-spheres interaction
* There is always a continuous interaction
between the constituents of the earth
spheres
Atmosphere------Water (forming waves)
Atmosphere----Lithosphere (weathering and erosion)
Lithosphere--Hydrosphere (dissolution and karsts).
Resources
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Include water, soil, metal, nonmetal and
energy.
Earth science study:Their formation, occurrence, maintaining
supplies, and the environmental impact
of their extraction.
Divided into :
Renewable & nonrenewable resources.
The origin of universe
There are several hypothesis:Nebular Hypothesis.
The Big Bang Theory.
‫‪The Origin of Universe‬‬
‫•‬
‫تنص نظرية االنفجار العظيم على أن كل ما نعرفه في الكون من مادة وطاقة وزمان و‬
‫مكان كان موجودا في حيز صغير جدا يدعى الذرة البدائية التي تمتاز بكثافاتها‬
‫الالنهائية ودرجة الحرارة العالية جدا‪ 13.7( .‬مليار عام)‬
‫* في لحظة الصفر‪ ،‬حدث انفجار كبيرا جدا (طبيعة االنفجار غير واضحة)‪ ،‬ادى الى تطاير‬
‫مادة الكون الى اتجاهات مختلفة و بسرع كبيرة جدا ‪ ،‬من ذرات‬
‫الهيليوم و الهيدروجين‪.‬‬
‫* انخفضت درجة الحرارة في جميع أنحاء الكون‪ ،‬وقد تطورت المادة من الذرات البدائية‬
‫إلى الكترونات وبروتونات ونيوترونات ‪ ،‬وانتهت بتكوين ذرات العناصر الخفيفة التي‬
‫كونت النجوم ومن ثم المجرات‪.‬‬
Origin of the Earth.
1- Heating processes:a- Meteorites impact.
b- Radioactivity decays.
These processes leads to:Melting of the internal components (Rocks, minerals) of the earth and
forming the internal structure of the earth (Crust, Mantle, outer core, and
inner core).
- The high density materials sink down to the core of the earth. (Fe, Ni).
- The low density materials floating and crystallize near the surface.
- Different Kinds of gases have been released from the minerals crystals to
form the atmosphere
Origin of the Earth.
*The Paleo -atmosphere was Free of Oxygen.
*Blue- algae uni-cell played a good role for supply the atmosphere
by a free Oxygen. Which is an important for organisms life.
2- Cooling processes:* Cooling processes leads to:* condensation of water vapor in the atmosphere, and then leaks
and infiltrate to the basins, to form the currently oceans and
Seas.
*The Age of the earth is 4.6 B.y