Geology

PlotMaker

Geology27th June 2008

VENKAT M.

QA-Minex

GEOLOGY

GEO – Earth

LOGUS – Speech/Study

Geology – Study of earth

27 August 2010 Copyright 2007, Gemcom Software International Inc.

James Hutton, the Scottish geologist, naturalist, chemist

and experimental farmer, is the father of modern geology.

The Crust The thin skin of Earth - 3 to 40 miles

thick.

The Mantle This deep layer of warm rock accounts

for two-thirds of the mass of our planet.

The Outer Core Made of molten iron, nickel, and

Earth


The Outer Core Made of molten iron, nickel, and

other ingredients yet to be determined. Streaming

at possibly one to several miles per week.

The Inner Core a ball of iron alloy one-third the

size of the moon in the center of earth. This metal

ball is broiling hot at 11,000 degrees Fahrenheit,

comparable to the surface of the sun, but it

remains solid because of the enormous weight of

all the rest of Earth bearing down on it.

Earth - Magnet

The rotational forces of the liquid

iron are reasonable for the earths

magnetism.

So, there is true and magnetic


So, there is true and magnetic

north due to the tilt in the axis of

rotation of the earth.

The angle between true and

magnetic north is called

Declination.

• The Earth's surface is made up of a

series of large plates (like pieces of a

giant jigsaw puzzle).

• These plates are in constant motion

travelling at a few centimeters per

year.

Plate Tectonics


year.

• Convection currents beneath the

plates move the plates in different

directions.

• The source of heat driving the

convection currents is radioactive

decay which is happening deep in

the Earth.

Plate Tectonics A Small Video


• The geological time scale is used by

geologists and other scientists to

describe the timing and relationships

between events that have occurred

during the history of Earth.

Geological

Time Scale


• The vast expanse of geological time

has been separated into eras,

periods, and epochs.

• Younger formations are on top and

as we go down in GTS we will get the

older formations and between each

formation there is a unconfirmity.


• Naturally occurring

• Solid crystalline substance

• Generally inorganic

Mineral

A Founded in nature, not synthetic.

Composed of atoms arranged in

an orderly, repeating, 3-D array.


• Generally inorganic

• With a specific chemical

composition.

Formed independently of

plants and animals (organic

material - carbon).

Unique combination and arrangement of

atoms: can be represented with a chemical

formula.

Minerals

Examples: Gold, iron, copper, salt, diamonds,

feldspar, calcium, phosphorus, etc.


IronFeldspar Gold

MoreMore thanthan oneone kindkind ofof

mineralmineral stuckstuck togethertogether

Rocks


mineralmineral stuckstuck togethertogether

formsforms aa ROCKROCK..

Rocks - Types

Igneous

Sedimentary


Sedimentary

Metamorphic

Rocks - IGNEOUS

• Deep inside the Earth, rocks and minerals melt under tremendous

heat. This forms magma.

• When the magma cools back down, it hardens and forms new

rocks. These rocks are called IGNEOUS rocks.


Rocks - IGNEOUS


EXTRUSIVE

Forms when lava cools quickly on the Earths

surface

Forms from molten rock

cooling and solidifying

INTRUSIVE

Magma cools slowly over millions of years deep beneath the surface –results in Crystalline

formations

Rocks - IGNEOUS


Rocks - IGNEOUSThese BASALT columns near Fingal’s

Cave form the base of the Scottish

island of Staffa. The columns formed

when cooling lava flows met bedrock

and the region’s cold weather.


Rocks - IGNEOUS

Mount Rushmore - Keystone, South Dakota


Rocks - IGNEOUS


BASALT – Extrusive igneous rock GRANITE – Intrusive igneous rock

Rocks - SEDIMENTARY

Weathering and Erosion

Transportation Deposition


Compaction and Cementation

Sedimentary Rock

Rocks - SEDIMENTARY

Sedimentary rocks are divided into two categories

Chemical

Mineral are dissolved in to the water…water is evaporated off and leaves behind chemical

Clastic

Made from eroded fragments of other rocks


evaporated off and leaves behind chemical sedimentary rocks

Examples - Limestone & Gypsum

fragments of other rocks

Shale

Sandstone

Conglomerate

Rocks - SEDIMENTARY


Sandstone Limestone Shale Conglomerate

Rocks - SEDIMENTARYBryce Canyon, Utah.

The sea dried up, the sandstone was uplifted to form a vast plateau.The Paria River eroded the layers to form the spectacular scenery.


Rocks - SEDIMENTARY


Rocks - SEDIMENTARY


Hatshepsut Temple, Luxor, Egypt.

This Temple was carved directly from the limestone cliff walls.

Rocks - METAMORPHIC

• When rocks are subjected to

greater heat and pressure inside

the Earth, they are changed into

rocks which are different from the

original.

Meta – Change , Morphos - Shape , Metamorphic – Change in shape or form


• This change occurs while the

original rocks are still in a solid

state.

• Thus the new rocks formed are

called metamorphic rocks.

Rocks - METAMORPHIC

Two types of metamorphism


Contact

Rock surrounding a magma body get

cooked and changes due

Regional

Tectonic forcesMetamorphism

occurs over a large area

Rocks - METAMORPHIC


Rocks - METAMORPHIC


Rocks - METAMORPHICParent Rock Metamorphic Rock

Granite Gneiss

Shale Slate


Sandstone Quartzite

Rocks - METAMORPHIC

Michelangelo's Pieta

• Made of marble resulted from

the metamorphism by heat of

limestone or dolomite.


• Usually whitish but can be

found in other colours due to

impurities.

Rocks - METAMORPHIC

Mt Arapiles, Australia isa world famous rockclimbing site.


Mountain is quartzite.

Rocks - METAMORPHICTAJ MAHAL

Finished in 1648 with Red sandstone base.Marble walls inlaid with semiprecious gems.


Rock

Cycle


Cycle

CoalCoal isis formedformed byby thethe decompositiondecomposition ofof

organicorganic (vegetable)(vegetable) mattermatter underunder highhigh

pressurepressure andand heatheat.. ItIt isis neitherneither MineralMineral

nornor RockRock butbut it’sit’s aa fossilfossil fuelfuel..



Coal – Stages of

Formation


PEAT LIGNITE BITUMINOUS ANTHRACITE

Geological

Map of INDIA


Map of INDIA

Strike - Dip


• Strike – A horizontal line used to represent the orientation/direction/trend

of the beds.

• Dip – It is the angle from horizontal in which the beds are lying.

Fault & Fold

• Fault (def)- a break in a body of rock along

which some displacement has occurred.


• Fold (def)- a bend in a body of rock, which is

generally being squeezed.

Fault & Fold - Mechanism

F

O

L

D

F

A

U

L

T

Fault – Normal Fault


• Normal Faults are produced by tensional forces.

• The upper block (Hanging wall) moves down to the lower

block (Foot wall).

Fault – Reverse Fault


• Reverse Faults are produced by Compressive forces.

• The upper block (Hanging wall) moves up relative to the lower

block (Foot wall).

Fault – Strike Fault


• Strike Faults are produced by shearing forces.

• The movement of the blocks is along strike direction.

Fault –Strike Fault

San Andreas Fault, California


Fold – Terminology


Fold – Anticline


Anticlines are folds where the originally horizontal strata has been folded

upward, and the two limbs of the fold dip away from the hinge of the fold

Fold –Syncline


• Synclines are folds where the originally horizontal strata have been folded

downward, and the two limbs of the fold dip inward toward the hinge of the fold.

• Synclines and anticlines usually occur together such that the limb of a syncline is

also the limb of an anticline.

Folds


Few more Geological Terms…


Few more Geological Terms…


Bedrock - The general term referring to the rock

underlying other unconsolidated material, i.e. soil.


Sills and dykes are formed when magma intrudes into rock. Sills form where magma

intrudes between layers, they run parallel to the layer. Dykes form when magma intrudes

into a rock along lines of weakness such as fractures and fissures. Dykes cut beds and

range in size from a few cm to several km.

OutcropOutcrop –– AnyAny placeplace wherewhere bedrock/seambedrock/seam isis visiblevisible onon thethe

surfacesurface ofof thethe earthearth..



Intrusion – A sudden

appearance of different

rock in the middle of


rock in the middle of

other rock formation.

Questions…

Please


Please

Finally…

VENKAT M.

QA-Minex

Geology

Education

gemcom software international

rocks igneous

igneous rocks

rocks sedimentary

rocks types

rocks metamorphic

forms new rocks

rest of earth