THE Solid EARTH The earth formed approximately 4.6billion year ago from a nebular cloud todust and gas that surrounded the sun. Thedusty material accreted to the nebularmidplane where it formed progressivelylarger clumps. Eventually bodies ofseveral kilometers in diameterformplanetesimalsed; these are known as.
The three layers of earthThe crust- is the thinnest layer in theearth, making un only 1 percent of the massand 2 percent of the volume.The mantle- is the largest layer in theearth, making up about 82 percent of thevolume and 68 percent of the mass of theearth.The core- makes up 16 percent of thevolume of the earth and about 31 percentof the mass.
Minerals and RockMINERALS Must be distinguished from rock. A mineral is a chemical compound with a given composition and a defined structure.ROCKS is a mixture of one several minerals, in varying proportion.
Other Meaning for Rock Rock are hard mass of theearth’s surface. Some are just afew million years old. Othersformed almost 4 billion years ago.When the earth was young theyare always being added to a newrock forms.
THE THREE TYPES OF ROCKS
Igneous rocks Igneous rock (derived from the latin word igneus meaningof fire, from ignis meaning fire) forms through the cooling andsolidification of magma or lava. Igneous rock may form with orwithout crystallitation, either below the surface as intrusive(plutonic) rocks or on the surface extrusive(volcanic) rocks. Thismagma can be derived from partial melts of pre-existing rocks ineither a planets mantle or crust. Typically, the melting is causedby one or more of three processes: an increase in temperature, adecrease in pressure, or a change in composition. Over 700 typesof igneous rocks have been described, most of them havingformed beneath the surface of Earths crust. These have diverseproperties, depending on their composition and how they wereformed.
Sedimentary rocks Sedimentary rocks are types of rock that are formedby the deposition of material at the Earths surface andwithin bodies of water. Sedimentation is the collectivename for processes that cause mineral and/or organicparticles (detritus to settle and accumulate or for mineralsto precipitate from a solution. Particles that form asedimentary rock by accumulating are called sediment.Before being deposited, sediment was formed byweathering and eroison in a source area, and thentransported to the place of deposition by water, wind, ice,mass movement or glacier which are called agents ofdenudation.
Metamorphic rocks Metamorphic rocks arise from thetransformation of existing rock types, in a processcalled methamosposis, which means "change inform". The original rock (protolith) is subjected toheat and pressure, (temperatures greater than 150to 200 °C and pressures of 1500 bars) causingprofound physical and/or chemical change. Theprotolith may be sedimentary rocks, igneous rockor another older metamorphic rock.
Diastrophism Diastrophism refers to deformation of the Earths crust, andmore especially to folding and faulting. Diastrophism can beconsidered part of geotectonics. Diastrophism comes from theGreek word meaning a twisting. Cases of Diastrophism Movement The result of pressure exerted by convection currents in the mantle. Meteorite impact Combination of gravity and erosion
VOLCANISMis the phenomena connected withvolcanoes and volcanic activity. Itincludes all phenomena resultingfrom causing magma within the crustor mantle of a planet to rise throughthe crust and from volcanic rocks onthe surface.
Driving forces of VolcanismPLATE TECTONICS from late(tectonicus) from the Greek (pertaining to building) is a scientific theory that describes the large scale motions of earth lithosphere. movement of molten rock in the planet mantle caused by thermal convection currents, couple with gravitational effects of changes on the earth surface
Aspects of VolcanismVolcanoes are place where magma reaches the earth surface.Intrusions these are formed where magma pushes between existing rock, intrusions can be in the form of batholiths, dikes, and layered intrusions.Hydrothermal vents these includes Geyser, Hot spring, and munpots. They are often used as a source of geothermal energy.
Volcanic Winter the amount of gas and ash emitted by volcanic eruption has a significant effect on the planet climate. EARTHQUAKEalso known as quake, tremor or temblor. Is theresult of a sudden release of energy in the earth’scrust that create seismic wave.are generally associated with plate tectonicsactivity but some earthquakes are generated as aresult of volcanic activity.