What is

Physical Geology all about?

Physical Geology examines the ...

Earth materials,Earth processes, Earth’s surface morphology,Earth’s internal structure,Earth evolution, Earth resources and Earth environment.

... so as to understand and solve the problems related to ...

Earth environment, e.g., global warming, climate change, floods, hurricanes, aridity etc., and

Earth resources, e.g., the impen-ding energy crisis.

Earth hazards, e.g., earthquakes, volcanism, tsunamis etc.

Science is a continuous quest for the basic rules that apply equally all over the universe.

Scientificmethod

Literary

Self-evident truth

Untestedopinion

Postula-tional

The Scientificmethod

Literary

Self-evident truth

Untestedopinion

Postulational

Inte

rpre

tati

ve id

ea

s

Em

piric

al or o

bs

ervab

le data

Existentialism (informal process)

Rationalism (formal structural proof)

But the experimentation often needed for such a quest is seldom available in the geological sciences.

No proposal or idea is scientific, therefore, unless it is amenable to falsification.

How does geology solve this problem? Distinguish law from postulate and theory.

Linearize, e.g., using the radiometric decay principle to date geo-logical past.

Seek independent evidences, e.g., gravity, seismicity and geomag-netism to map earth’s internal structure.

Earth, the “Third Rock from Sun” is also called the “Lonely Planet” because, to

our knowledge as yet, earth is the only

planet with evidence of life and it is water that

creates this uniqueness.

This uniqueness This uniqueness comes from two comes from two cycles that define cycles that define the Earth ...the Earth ...

hydrological cycle;

and

plate tectonics.

Evaporation320,000 km3

Ocean Storage1,370,000,000 km3

Precipitation285,000 km3

Precipitation95,000 km3

Evaporation60,000 km3

Run-off: 35,000 km3

A conceptual look at the hydrological cycle

HydrogenHelium

OxygenCarbon

Nitrogen

SiliconNeon

MagnesiumIron

SulphurAluminum

CalciumNickel

SodiumArgon

ChromiumPhosphorous

ManganeseChlorine

PotassiumOther elements

HHe

OCN

SiNeMgFeSAlCaNiNaArCrPMnClK

74.50023.840

0.82000.37500.0910

0.08300.05500.05700.10400.03800.00660.00740.00920.00330.00300.00320.00090.00110.00060.0003

29.8

15.6

13.933.3

1.51.82.00.2

1.9

46.6

27.7

2.15.0

8.13.6

2.8

2.61.5

UniverseWholeEarth

Earth’sCrust

Outercore

The whole earth is richer in Fe, Mg and Ni, and poorer in Si, K and Al, than what

is found on the earth’s surface.

Whole Earth density = 5.5 gm/cm3

Density of the crust = 2.7 gm/cm3

Mantle

Co

re

CrustRo

ckyM

etallic Innercore

The principle of superposition of strata: In an

undisturbed succession

of layers, the one at

the bottom is the

oldest.

Present is the key to the past, i.e., the geological processes today are the same as they have always been.

Mount Annapoorna, 26,545 ft (8,091 m)

                                

Bibi ka Makbara, Aurangabad