What is Physical Geology all about?
Jan 05, 2016
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