Composition of rocks

A rock can be defined as a solid substance that occurs naturally because of the effects of three basic geological processes: magma solidification; sedimentation of weathered rock debris; and metamorphism. As a result of these processes, three main types of rock occur:

Igneous rocks- produced by solidification of molten magma from the mantle. Magma that solidifies at the Earth's surface conceives extrusive or volcanis ingenous rocks. When magma cools and solidifies beneath the surface of the Earth intrusive or plutonic ingenous rocks are formed.

Sedimentary rocks- formed by burial, compression, and chemical modification of deposited weathered rock debris or sediments at the Earth's surface.

Metamorphic rocks - created when existing rock is chemically or physically modified by intense heat or pressure.

Element	Chemical Symbol	Percent Weight in Earth's Crust
Oxygen	O	46.60
Silicon	Si	27.72
Aluminum	Al	8.13
Iron	Fe	5.00
Calcium	Ca	3.63
Sodium	Na	2.83
Potassium	K	2.59
Magnesium	Mg	2.09

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GROUNDWATER

What is groundwater?

-Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of lithologic formations.

-A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table.

-Groundwater is recharged from, and eventually flows to, the surface naturally; natural discharge often occurs at springs and seeps, and can form oases or wetlands.

-Groundwater is also often withdrawn for agricultural, municipal and industrial use by constructing and operating extraction wells.

-The study of the distribution and movement of groundwater is hydrogeology, also called groundwater hydrology.

The uses of groundwater

- Groundwater is hypothesized to provide lubrication that can possibly influence the movement of faults. It is likely that much of the Earth's subsurface contains some water, which may be mixed with other fluids in some instances

- Groundwater makes up about twenty percent of the world's fresh water supply, which is about 0.61% of the entire world's water, including oceans and permanent ice. Global groundwater storage is roughly equal to the total amount of freshwater stored in the snow and ice pack, including the north and south poles.

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Composition of earth

Earth is a terrestrial planet,meaning that it is a rocky body,rather than a gas giant like Jupiter. It is the largest of the four solar terrestrial planet both in terms of size and mass. Of these four planets, Earth also has the highest density, the highest surface gravity, the strongest magnetic field and fastest rotation, It also is the only terrestrial planet with active plate tectonics.

Chemical Composition of the Crust[56]
Compound	Formula	Composition
		Continental	Oceanic
silica	SiO2	60.2%	48.6%
alumina	Al2O3	15.2%	16.5%
lime	CaO	5.5%	12.3%
magnesia	MgO	3.1%	6.8%
iron(II) oxide	FeO	3.8%	6.2%
sodium oxide	Na2O	3.0%	2.6%
potassium oxide	K2O	2.8%	0.4%
iron(III) oxide	Fe2O3	2.5%	2.3%
water	H2O	1.4%	1.1%
carbon dioxide	CO2	1.2%	1.4%
titanium dioxide	TiO2	0.7%	1.4%
phosphorus pentoxide	P2O5	0.2%	0.3%
Total		99.6%	99.9%

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