Geology as a Discipline2

8/14/2019 Geology as a Discipline2

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Geology as a Discipline

A science that examines theearth, its form and composition,

and the changes it hasundergone and is undergoing.

DIVIDED INTO TWO BIG AREAS;

Physical Geology-the study of thematerials composing the earth and

the processes and phenomena that

operate beneath and upon its surface.


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Historical Geology deals with the study of

theevolution of the earth. It continues to establish a

systematic chronological arrangement of the

biological and physical changes that have taken

place in the geologic

past.


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o called Ayers Rock located in Australiircumference of around 9.4 km and risi

ht of 348 km. One of the largest rock mrld


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Mt. St. Helens

Located insouthwestern

Portion of

washington.

It erupted last 1980,

With this eruption, theMountains elevation

Dro ed from


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GEOLOGIC PROCESSES

1. Endogenic processes-expansion of oceanic crust andcontinual drifting of continentalcrust

Diastrophismis a general term for all crustalmovements produced by endogenic Earth forces

that produce ocean basins, continents, plateaux,and mountains


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Geotectonic cycle relates these largerstructural features to gross crustal movements

and to the kinds of rocks that form variousstages of their development.

Orogenesis,or mountain building,

tends to be a localized processthat distorts pre-existingstrata.

Faulting- commonly associated withplate boundaries

Volcanic eruptions and earthqua


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EXOGENIC PROCESSES

Any natural medium capable of picking up and movingearth material is referred to as a geomorphic agent.

Running water, groundwater,glaciers, wind, and movements withinbodies of standing water (such astide, waves, and currents) are allprimary geomorphic agents.

Because they originate outside the Earth's crust, these

geological processes are designated as epigene orexogenic.


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1.Weathering is a collective name for agroup of processes responsible for thedisintegration and decomposition of rockin place.

Physical, chemical, or biologicalweathering is a prerequisite to erosion.

2.Mass wasting (the gravitative transferof material downslope) involves creepand such actions as earthflow, debrisavalanches, and landslides.

3.Hydraulic action is thesweeping away of loose

material by running water; the


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Devil Tower- monolith; an erodedvolcanic pillar


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The land surfaceThe water surface

The interior structure of the Earth

MagnetosphereAsthenosphere


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Lithosphere or the rocksphere

Features such as plains, valleys,

mountains, hills, and plateaus

Covering the land features in most places

is a layer of loose materials composed of

soil, rock, sand, large boulders, gravel,

and clay.


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HYDROSPHERE

The lower portions of the earthssurface are filled up with water whichforms the water basin.

It covers 70% of the earths surface.

The oceans are great in depth, too.They are deeper than the highest land

Surface. Mt. Everest is only 8,800 mHigh while the Marianas Trench is11, 034 m. deep.


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THE INTERIOR STRUCTURE

OF THE EARTH

Crust this is the layer where alllife on earth exist.

The three types of solid rock igneous, sedimentary, and metamoare found there.

- relatively thin but the crust does

not have the same thickness everyw- it can be studied by drilling into it- the only layer that can be seen an

studied directly.


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MANTLE

- is about 2,990 km thick In 1909,a Yugoslav scientist, Andriga Mohorovicic,

noted a marked change in the way earthquake waves

travel after they

reach a depth of 16 km. He was able to show that this iscaused by a zone of difference in density between the

rocks of the crust and those of the mantle below. The

zone is no known as Mohorovicic discontinuity or simply

Moho.


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MAGNETOSPHERE

Is a magnetic field that surrounds the earth. It isstrongly distorted by the solar wind.

In 1600, William Gilbert found that the earth is a

giant magnet based from the experimented heconducted.

Earth has geomagnetic poles which are the pointson its surface through which the magnetic axis of

the earth passes.

Scientists think that the magnetic field is due to thepresence of the dense iron in the inner core.


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GLOMAR CHALLENGER

Deepest drilling was done by thisship.

explored the great Rift Valley of the

Mid-Atlantic Ridge, south-west of theAzores. The rift valley is considered bygeologists as the separation betweenthe Eurasian plate and the NorthAmerican plate of the Earth's crust, and

it constitutes one of the many sites inthe ocean bottom where molten rockoozes forth to form new crust.


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ATMOSPHERE THE LAYER OF AIRCOVERING THE EARTH Layers of Atmosphere:

1. TROPOSPHERE- lowest layer; most of theair is found. Ave height of 16-18 km above, itis where weather phenomena occur andwhere winds and clouds are found.

2. STRATOSPHERE extends to a height of85 km. Ozone layer is located here. Mostmeteorites are burned up in this layer.

3. IONOSPHERE- extends to a height of 1,000kms. It can reflect radio messages to earth. A

region of electrically charged particles orions.

4. EXOSPHERE outer space, there arevery few molecules thinly scattered in space.

Geology as a Discipline2

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