Lecture 3 and 4 Dr. Mohammed Ajjour

1. Lecture 3 and 4 Dr. Mohammed Ajjour Introduction University Of Palestine 2009,

2. Chapter 1The Earth and Life • 4.6 Billion years ago , Sun and other planets were formed from Premordial Nebula. • During the first some million years, some redistribution of elements of the Earth took place and Volcanoes erupted. • In Low areas condensation of water vapour from volcanoes formed water in oceans and seas ( sweet water first, later salty from rocks).This process is still ongoing. • Atmosphere gases accumulated from volcanoes ( water vapour, hydrogen sulphate, ammonia, nitrogen , argon and Helium ,no oxygen at this stage. Ultra violet radiation penetrated easily and oxygen formed through UV and H2O splitting was reduced immediately by Gases. • . University Of Palestine 2009, Dr. Mohammed Ajjour

3. Con. The Earth and Life • 3500 Million years ago some simple species of Bacteria were found, which are able to exist in absence of O2 and to photosynthesise CO2 to produce free oxygen. Some of these are still there. • Since the last 550 million years, the concentration of free O2 increased to present level allowing the existence of other species • At present ,these Species undergo different changes and adaptations.. • During this long history ,the geological processes produced minerals (Gold, diamond, phosphate, Iron..etc)and Fossil Energy Sources ( Oil, Coal, gas ). • At the last end Human life began • 3500 Million years ago some simple species of Bacteria were found, which are able to exist in absence of O2 and to photosynthesise CO2 to produce free oxygen. Some of these are still there. • Since the last 550 million years, the concentration of free O2 increased to present level allowing the existence of other species presence of Oxygen. At present ,these Species are undergoing different changes and adaptations.. • During this long history ,the geological processes produced the minerals ( like Gold, diamond, phosphate, Iron...etc)and Fossile Energy Sources ( Oil, Coal, gas ). University Of Palestine 2009, Dr. Mohammed Ajjour

4. Earth Sphers The planet Earth , in which we live, and its surrounding is divided into five spheres or systems, which interact with each other and affect our live: • Lithosphere or the rocky stony part. • Pedosphere or the soil Part. • Hydrosphere or the watery part. • Atmosphere or the gaseous part. • Biosphere or the living parts. Energy and matter move between the spheres and organism can live in. University Of Palestine 2009, Dr. Mohammed Ajjour

5. Earth and lithosphere • At its centre, the Earth has a solid inner core, 1370 km in radius, made from iron with some nickel. • This is surrounded by an outer core, about 2000 km thick, also of iron with nickel, but liquid, although of very high density. • Movement in the outer core acts like a self- exciting dynamo and generates the Earth’s magnetic field. • Outside the outer core, the mantle, made from dense but somewhat plastic rock, is about 2900 km thick

6. Earth and lithosphere • At the surface there is a thin crust of solid rock, about 6 km thick beneath the oceans and 35 km thick (but less dense) beneath the continents. • The outer surface with a Thickness 0f100-120km is called the lithosphere University Of Palestine 2009, Dr. Mohammed Ajjour

7. lithosphere • Composed of solid RocksThickness : 100-120 Km, including the Crust and upper mantel. • Divided into plates that are in constant movements • -Continents, Earthquakes and volcanoes result from this movements Uniare the results versity Of Palestine 2009, Dr. Mohammed Ajjour

8. The structure of the Earth • On Earth, but possibly on no other solar-system planet, the crust consists of blocks, called ‘plates’, which move in relation to one another. The theory describing the process is known as ‘plate tectonics’ (GRAHAM, 1981). • There are seven large plates, a number of smaller ones, and a still larger number of ‘micro plates’. The boundaries (called ‘margins’) between plate can be constructive, destructive, or conservative. • constructive margins two plates are moving apart and new material emerges from the mantle and cools as crustal rock to fill the gap, marked by a ridge. There are ridges near the centers of all the world’s oceans. • Slowly but constantly the movement of plates redistributes the continents carried on them University Of Palestine 2009, Dr. Mohammed Ajjour

9. pedosphere • Soil is the upper fragments that result from weathering of rocks. • In addition to its minerals, soil contain water, air and organic matter that are necessary to support plant growth on soil surface. • Quality of soil is determined by its origin and many internal and external factors ( climate, Topography….) • Function of soil :in addition to its function as a place to live in and a source for row material, soil are :Important for Forest and crop production, decomposition of organic matter ,absorption of rain and recharge of ground water , stabilization of Ph of soil solution , and filtration of organisms , other particles , other minerals from Entering into ground water University Of Palestine 2009, Dr. Mohammed Ajjour

10. Hydroshere • It includes all kinds of water in rivers, lacks, Oceans, seas, rainfalls , ground water , snow and ice. • More than 70% of earth surface is covered by water • Quality of water is variable and depends on its mineral and salt contents. • Water plays an important role by affeecting earth surface and its structure ( assisting the fragmentation and sedimentation of rocks, accumulation of clay or sandy sediments) University Of Palestine 2009, Dr. Mohammed Ajjour

11. Atmosphere University Of Palestine 2009, Dr. Mohammed Ajjour

12. Biosphere University Of Palestine 2009, Dr. Mohammed Ajjour

13. Cont. The structure of the Earth • destructive margin Where plates move towards one another marked by a trench where one plate sinks (is sub ducted) beneath the other. • At conservative margin two plates move past one another in opposite directions . There are also collision zones, where continents or island arcs have collided. In these, all the oceanic crust is believed to have been sub ducted into the mantle, leaving only continental crust. Such zones may be marked in various ways, one of which is the presence of mountains made from folded crustal rocks. University Of Palestine 2009, Dr. Mohammed Ajjour