Introduction To Geosciences 1

INTRODUCTION TO GEOSCIENCES
1
1. GEOLOGY AS A SCIENCE
Earth Sciences or Geosciences, like other sciences, are

constantly evolving.
Until the 19th century, the Earth sciences were

structured, which served for the conquest and
exploitation of natural resources on all continents.
Earth Sciences are not only knowledge of something

physical, they are also tools that help us plan a rational
exploitation of our natural resources.
INDUSTRIAL UNIVERSITY OF SANTANDER - INTRODUCTION TO GEOSCIENCES 2

Geo. Javier Enrique Peña Manosalva
• DEFINITION :
Grouping of sciences or disciplines that study the

structure, form and dynamics of the earth.
Part of the knowledge that is dedicated to the study of
the physical components of the planet.

• RELATED SCIENCES:
Geology : Rocky part of the Earth (Lithosphere)
including the core, mantle and crust. The subdisciplines
as geophysics, geochemistry,
paleontology, mineralogy, petrology, stratigraphy and
sedimentology.
Oceanography, limnology and hydrology : They
describe the marine and sweet domains of the aqueous
parts of the Earth (Hydrosphere). Subdisciplines such as
hydrology and oceanography, physics, chemistry and
biology.
Atmospheric Sciences : Gaseous parts of the Earth
(Atmosphere).
Glaciology : Frozen parts of the Earth
(Cryosphere).

• IMPORTANCE OF GEOLOGY
INDUSTRIAL UNIVERSITY
Ge
6
1. GEOLOGY A SCIENCE
AS
• SPECIALTIES OF GEOLOGY
Geophysics: Study of the physics of the earth, gravity anomalies,

discontinuities in the prolongation of seismic waves-seismology, the
earth's magnetic field .
Geochemistry http://plata.uda.cl/minas/apuntes/geologia/geologiageneral/ggcap02.htm : The
distribution of chemical elements in different parts of the Earth's
crust. Chemical composition of different rocks and minerals.
Mineralogy: Study of minerals. Internal structures of minerals,
chemical composition, classification.
Petrology: Study of rocks, their origin, the processes of their
formation, their composition.
Petrography: It is a branch of petrology, which deals with the
description of rocks, their mineral content and texture, and the
classification of rocks.
INDUSTRIAL UNIVERSITY OF SANTANDER - INTRODUCTION TO GEOSCIENCES

Geochemistry: The distribution and abundance of elements in the
earth and attempts to explain the distribution of elements in rocks
through geological processes.
Structural geology: Analysis and interpretation of tectonic
structures in the earth 's crust . Knowledge of the forces in the crust
that produce Faults-Folds-Orogenesis.
Regional Geology: Geology of different regions such as South
America, Europe, Chile, in detail.
Historical Geology: Geological eras from the formation of the
earth approximately 4.6 Ga (=4600Ma) ago until today.
Paleontology: Life of past geological epochs; Study of fossils:
Classification, recognition.
Stratigraphy: Stratified rocks, due to their nature, their existence,
their relationships with each other and their classification.

Sedimentology: Sediments (sand, sandstone, gravel,
conglomerate) and its formation.
Soil mechanics: The properties of soils to find land suitable for
construction, to calculate and avoid geological risks .
Hydrogeology: Investigations of the quantity and quality of
groundwater. It is about the interaction between rock, soil and
water.
Economic Geology: Exploration of metallic or non-metallic
deposits. Evaluation of the economics of a mineral deposit or
product.
Exploration/Prospecting: Search for geological deposits with
economic value.
Environmental Geology: Search for contaminated sectors, forms
and processes of contamination.

• HISTORY OF GEOLOGY
XENOPHANES (600 years before Christ ): Fossils were animals

that lived before.
HERODOTOS (450 years BC): A flood of the Nile River produced a
very thin layer of sediments, he concluded that the formation of the
Nile delta must have happened within several thousand years.
STRABO (63 BC) Christ -19 after Christ): Movement of the earth in
a vertical manner, that is why there are fossils from the sea in the
high mountains. Explanation of tectonic forces.
AVICENNA (980-1037): Classification of Minerals, description of
sedimentary rocks, erosion. Geological processes are slow not like a
flood in action.
BIRUNI (973-1048): Measurement of the specific weight of
minerals.

LEONARDO DA VINCI ( 1452-1519) : He described fossilization,

the change from an animal to a fossil. He rejected the idea of a
world flood.
FRA CASTO RO (1 5 17): Why did the animals that lived in the sea
die because of a global flood?
AGRICULTURAL ( 1494-1555): The first scientific books on
geology and metallurgy.
STENO or STENSEN, Nils (1638-1687): The first geological law:
The upper strata are younger than the lower strata.
The 18th century : Two competing theories:
a) Neptunists: All rocks have their roots in deposition in the seas
(WERNER)
b) Plutonists or Vulcanists: All rocks are formed by magma (they
come from a foundry) (HUTTON)
SMITH, William (1769-1839): Second geological law: Each

stratum has its characteristic fossil content.
LYELL (1797-1875): Principle of actualism: The processes in the
past were the same as today and vice versa.
DARWIN, Charles : Published 1859 "On the Origin of species by
natural selection.
DANA (1873): Theory of geosynclines: explanation of mountain
formation.
KELVIN (1897): Kelvin deduced the age of the Earth from its
cooling rate: 20-40 million years (he did not take radioactivity into
account).
RUTHERFORD (1905): First measurement of an absolute age
(U/He): Age of the earth greater than 2 ga. (2.000.000.000).

Until 1906 : Geotectonic theories : theory of the expansion of the earth,

theory of the contraction of the earth and the theory of
clinal geosynclines (All theories used fixed-stable continents) WEG ENER
( 1912) Continental drift theory : The continents are floating (they move!)
some separated or collided: This theory was rejected at this time , but in
the '60s/'70s it was accepted by the vast majority of scientists.
NIER & MATTAUCH (1930): First mass spectrometer, to determine
different isotopes of an element.
SCHUCHERT (1931): Radiometric dating of the earth with 4 Ga. (4 giga
years = 4,000,000,000 years)

INDUSTRIAL UNIVERSITY OF SANTANDER *
- INTRODUCTION TO GEOSCIENCES
2____
2. THE
UNIVERSE
The universe 10 80 atoms
contains 10 50 tons. metrics
Age 20 billion years

Number of Galaxies 75 Million
stars in the milky way 75 Million
INDUSTRIAL UNIVERSITY OF SANTANDER

1
7
2. THE
UNIVERSE
VV Cephei (2400
biggest star
diameters of the sun)

1
8
2. THE UNIVERSE
• OLBERS paradox: The universe has to be finite (with
calculable volume).
• A "curved" 3-dimensional universe is finite but for human

beings it is unlimited.
• The universe is expanding
a) Big Bang
b) Redshift of light

1
9
2. THE
UNIVERSE
HOLISTIC THEORY
FOR MANY YEARS, physicists have tried to all forces (gravitational, electromagnetic, strong
explain the workings of the universe using a single nuclear and weak interaction). That theory should
scientific theory. Currently, they are developing a show that all subatomic particles can be deduced
"holistic theory" that can explain how they are from a single type of basic particle.
related
Unit
UNiFiMAT ---GRAVITY
COMBINATION OF FORCES
ION EECYR8Bs,, -EToMaGMeismg-
Scientists believe that originally
all the parties were combined
into a single one that was
ITEnAccionneg-
created at the beginning of the
Big Bang. SUPERSTRINGS

2
0
2. THE
UNIVERSE
toda
2
1
2. THE
• COMPOSITION OF THE UNIVERSE
UNIVERSE

2
2
2. THE
• COMPOSITION OF THE UNIVERSE
UNIVERSE
Universe m The earth

Living being
EI c • C EI Fait EIT Ye Mg
h N • h
TH Y TH N • h HE ah
Y
o o
Y Y
o o

2
3
2. UNIVERSE
THE GALAXIES
THE
SPIRAL
ELLIPTIC
AL
IRREGULAR
SANTANDER INDUSTRIAL
CTION TO GEOSCIENCES 2
4
2. THE UNIVERSE
• THE SOLAR SYSTEM AND THE PLANETS
Distance from the

Density (g/cm3) Composition of the
Name sun in millions of Diameter(km)
(Specific weight) atmosphere
km
Sun 0 1.392.000 1,41 ••
Mercury 58 4.835 5,69 does not have
Venus 107 12.194 5,16 CO2
Land 149 12.756 5,52 N2,O2

Moon - 3.476 3,34 does not have
Mars 226 6.760 3,89 CO 2 , N 2 , Ar
Jupiter 775 141.600 1,25 H 2 , He
saturn 1421 120.800 0,62 H 2 , He
Uranium 2861 47.100 1,60 H 2 , He, CH 4
Neptune 4485 44.600 2,21 H 2 , He, CH 4
Pluto 5860 14.000 ?4,2 9•

2
5
3.J.PLANET EARTH
2
6
3. PLANET EARTH
• THE SUN AND
THE EARTH
SANTANDER INDUSTRIAL ERSITY
2
7
3. PLANET EARTH
INTRODUCTION TO GEOSCIENCES
2
8
3. PLANET EARTH
• THE SUN AND THE EARTH
Seasons.
Distance Sun - Earth

2
9
3. PLANET EARTH
• THE SUN AND THE EARTH
SOLAR ENERGY:
At sea level they reach 0.7 KW/m 2
At a height of 3460m, 1.0 KW/m 2 reaches
SUN SPOTS:
Approx. Every 11 years the sun shows a maximum of sunspots.
Energy drops, this causes climate changes on earth.
SOLAR WIND:
Emission of electrons and protons, which produce the northern lights
in the polar regions. They affect radio communication
3. PLANET EARTH
THE MOON AND THE

EARTH

3
1
3. PLANET EARTH
• THE MOON AND THE EARTH
FORMATION OF THE MOON:

The moon is the same age as the earth. There are three theories of the
origin of the moon:
a) The earth captured the moon.
b) The moon separated from the earth.
c) Moon and earth formed together in a haze of matter.
THE TIDES:
The moon affects the earth through its gravitational field influence
3. PLANET EARTH
METEORITES
3
3
3. PLANET EARTH
INDUSTRIAL UNIVERSITY OF SA
- INTRODUCTION TO GEOSCIENCES 3
4
3. PLANET EARTH
• METEORITES
Small solid body from space that has fallen onto the surface. Every day
an amount of 1000 - 10,000 tons is reaching the earth.
TYPES OF METEORITES:
Meteoroids: Most of their particles are extremely tiny, they vaporize

when entering the atmosphere, generating only a light luminous trail
called a meteor.
Meteorite: It is a meteoroid that, upon entering the atmosphere, does
not completely vaporize and partially reaches the Earth's surface,
leaving exotic rocky material on it.
Bolide: Flash that accompanies the fall of a meteorite.
NTANDE
R
3. PLANET EARTH
• METEORITES
CLASSIFICATION ACCORDING TO ITS COMPOSITION:
Ferric meteorite (siderite): Fe-Ni alloy compound with a Ni content
between 4 - 20% (6 - 9%).
Hexahedrite: NEUMANN lines, they appear when corroding a polished surface.

Octahedrite: Figures from WIDMANSTÄTTEN, appear when slightly corroding a
polished surface. Its formation is explained by very slow cooling
from a high temperature.
Rocky or stony meteorite (aerolite): Silicate minerals mainly of olivine

and pyroxene with minor amounts of Fe-Ni.
Chondrites: They are olivine or pyroxene crystals in the form of small balls (=
chondrules) with a size of 1mm in diameter.
Achondrites: Without chondrules, with a coarse-grained crystalline texture.
First planetary bodies have on and recrystallization.
INDUSTRIAL UNIVERSITY OF SANTA NDER
3. PLANET EARTH
METEORITES
CLASSIFICATION ACCORDING TO ITS COMPOSITION:
Fero-rocky meteorite (siderolite): Consisting of a heterogeneous

mixture of Ni-Fe and silicates. According to the nature of the silicates, 4
classes of ferric-rocky meteorites are distinguished.
The abundance of meteorites on Earth is approximately as follows:
Meteorite type Abundance in % Properties
rocky meteorite 94 % Olivine Pyroxene
ferric meteorite 4,5 % Nor, Faith
Fero-rocky meteorite 1,5 % Yes, Nor, Faith
A
NTANDER
3. PLANET EARTH
• METEORITES
NTANDE
R
NDER
THE GEOSCIENCES 3
9
3. PLANET EARTH
• THE EARTH
GENERAL DATA:
Equatorial radius: 6378 km

Pole/pole radius: 6357 km
Volume: 1,083 X 1012 km 3
Mass: 6 X 1021 tons.
Average specific weight: 5.517 g/cm 3
Age: 4.65 billion years

Oldest rocks: 3.75 billion years old

1
3. PLANET EARTH
• THE EARTH
OCEANS - CONTINENTS:
Average height of land: 623 m
Average depth of the oceans: 3800 m
Ocean surface (total)
Surface of the Low depth sea deep sea

continents
9 X 10 7 km 2 27 X 10 7 km 2
18 % 53 %
29% 71%
15 X 10 7 km 2

4
2
3. PLANET EARTH
• THE EARTH
AGE:
1654 USHER: The earth was formed 4004 BC.
1715 HALEY: Estimation of age by the salts contained in the land and
sea.
1897 LORD CELVIN: 20-40 million years
1899 JOLY: 90 million years.
1931 SCHUCHERT: 4 billion years
Only the method by measuring the radioactive decay of some isotopes

(U, Rb, C) finally reached absolute ages of rock formation. Today we
know that the earth is 4.75 billion years old.

4
3
3. PLANET EARTH
• THE EARTH
COURT:

3. PLANET EARTH
• THE EARTH
INTERNAL STRUCTURE
0-40km: Continental crust is divided by the Conrad discontinuity, which is

not continuous, into an upper zone and a lower zone. The discontinuity is
located at a depth of 15 - 25km.
Generally the upper zone of the crust is made up of medium grade
metamorphic rocks. Its average composition is probably granodioritic.
The lower zone of the continental crust probably has a composition
similar to that of gabbros and basalts, that is, the elements Si, Al and Mg
are the main elements.
Moho discontinuity is the division between crust and mantle.

4
5
3. PLANET EARTH
• THE EARTH
INTERNAL STRUCTURE
up to 700km: Upper mantle of a solid, rigid lithosphere and an

underlying, plastic, partially molten asthenosphere.
700 - 2900km : Lower mantle
Gutenberg discontinuity is the division between mantle and core
2900 - 4980km : Liquid iron outer core

4980 - 6370km : Solid and dense inner core of iron

4
6
3. PLANET EARTH
• THE EARTH
THE CRUST:
Chemical % atoms % by weight

element
EITHER 62,1 46,5
Yeah 22,0 28,9
To the 6,5 8,3
Faith 1,8 4,8
AC 2,2 4,1
na 2,1 2,3
K 1,3 2,4
Mg 1,6 1,9
You - 0,5
4
7
3. PLANET EARTH
• THE EARTH
THE CRUST:
There are two types of bark:
The continental crust : Includes the continents and shallow sectors of the
sea.
The oceanic crust : It is found in deep ocean sectors.
The Earth shows a bimodal height distribution. That is to say, there are
two most common elevations on earth: 4700 m below sea level and
100 m above sea level. If there is only one type of crust, only one
more frequent bound with a Gaussian distribution is mathematically
expected UNIVERSIDAD INDUSTRIAL DE SANTANDER
4
8
3. PLANET EARTH
• THE EARTH
THE CRUST:
Continental crust (in

Chemical element
%) Oceanic crust (in %)
SiO 2 60,2 48,7
At 2 or 3 15,2 16,5
Faith 2 Or 3 2,5 2,3
Ugly 3,8 6,2
MgO 3,1 6,8

CaO 5,5 12,3
Na 2 O 3,0 2,6
K2O 2,9 0,4

4
9
3. PLANET EARTH
• THE EARTH
THE CRUST:
continental crust oceanic crust
Specific weight smaller (lighter) older (heavier)
Thickness thick (30-70km) Thin (6-8km)
Height between -200m to 8849m Bottom of the sea
Age maybe old younger (jurassic)
Rocks rich of yes poor si
0 0
deep ocean sediments (pelagic sediments)
0.5 km
up to 1.7 km pillow-type lavas
up to 1.8 km dikes (sheeted complex)
up to 3.0km: gabbro: magma chamber
10 below peridotite (from olivine and pyroxene) in the form of layers
km below peridotite without layer structure

5
0
3. PLANET EARTH
• THE EARTH
GEOPHYSICAL METHODS:
Geophysical methods take advantage of physical properties of rocks.

But all geophysical methods only give indirect information, that is, a
sample of a rock never comes out.
The most used methods are: Seismology.

Gravimetry.
Magnetometry.
Geoelectricity.

5
1
3. PLANET TIER
• THE EARTH
SANTANDER INDUSTRIAL NIVERSITY

3. PLANET EARTH
• THE EARTH
Seismology : They are based on the generation of seismic waves.
Seismic waves are mechanical and elastic waves, they cause non-
permanent deformations in the medium in which they propagate. The
deformation is constituted by an alternation of compression and
expansion in such a way that the particles of the medium move closer
and farther away.

5
3
3. PLANET EARTH

5
4
3. PLANET EARTH
• THE EARTH
Pu waves, longitudinal waves or compression waves: The
particles of a p, longitudinal or compression wave oscillate in the
direction of wave propagation. P waves are similar to ordinary sound
waves. P waves are faster than s waves.
Waves transverse waves or shear waves: The particles of an s,
transverse or shear wave oscillate perpendicular to the direction of
propagation. A distinction is made between sh waves, whose particles
oscillate in the horizontal plane and perpendicular to the direction of
propagation, and sv waves, whose particles oscillate in the vertical
plane and perpendicular to the direction of propagation. In polarized s
waves, their particles oscillate in a single plane perpendicular to their
direction of propagation.

5
5
3. PLANET EARTH
• THE EARTH
Rayleigh waves: Rayleigh (1885) predicted the presence of surface
waves by mathematically designing the movement of plane waves in a
semi-infinite elastic space. Rayleigh waves cause a rolling motion
similar to sea waves and their particles move in an ellipsoidal shape in
the vertical plane, which passes through the direction of propagation.
The speed of Rayleigh waves v Rayleigh is less than the speed of s
(transverse) waves and is approximately vRayleigh = 0.9 x Vs,
according to DOBRIN (1988).
Love waves: Love (1911) discovered the surface wave, which bears
his name by studying the effect of elastic vibrations to a surface layer.
Love waves require the existence of a surface layer of lower velocity
compared to the underlying formations. Love waves are shear waves,
which oscillate only in the horizontal plane, that is, Love waves are
horizontally polarized shear waves.
3. PLANET EARTH
• THE EARTH
Behavior of seismic waves in rocks:
Rock properties that influence these parameters are:
Petrography: Mineral content.

State of compactness.
Porosity: Percentage or proportion of empty space (pores) in a rock.
Filling: Of the empty space or that is, of the pores.
Rock texture and structure.
Temperature.
Pressure.

5
7
3. PLANET EARTH
• THE EARTH
Half Primary wave velocity (vp) in m/sec. Secondary wave speed (vs) in m/sec.
Granite 5200 3000

Basalt 6400 3200
Limestone 2400 1350
Sandstones 3500 2150
It can mainly be detected with seismology:

Reflection/Refraction of
Layer boundaries seismic waves
Failures
Pore fillers (such as petroleum)

5
8
3. PLANET EARTH
• THE EARTH
Gravimetry: Very important method in the search for mineral deposits.
This method takes advantage of the differences in gravity in different
sectors. Large mineralized bodies can increase gravitation in a given
region because larger rocks
Density increases acceleration.

5
9
3. PLANET EARTH
• THE EARTH
Gravity anomalies : A gravity anomaly is defined as the variation of the

measured gravity values with respect to normal gravity after the
necessary corrections have been applied.
The free air anomaly results from corrections for the influence of tides,
drift of the measuring instrument, latitude and altitude.
The Bouguer anomaly is obtained by applying all the mentioned
corrections

6
0
3. PLANET EARTH
• THE EARTH
Magnetometry: The Earth's magnetic field also affects deposits that
contain magnetite (Fe). These deposits produce an induced magnetic
field, that is, their own magnetic field. A magnetometer simply
measures magnetic anomalies on the Earth's surface, which could be
the product of a deposit.
SANTANDER INDUSTRIAL NIVERSITY

3. PLANET EARTH
• THE EARTH
Principle: The earth generates a magnetic field in the range of about

0.30000 to 0.65000G (= Gauss, or Oersted). This
This field can be compared to the field corresponding to a dipole (such as
a bar magnet) located at the center of the Earth, whose axis is inclined
with respect to the Earth's axis of rotation. By convention, the magnetic
pole located near the geographic North pole is called the magnetic North
pole and the magnetic pole located near the geographic South pole is
called the magnetic South pole. The geomagnetic field is not constant but
rather undergoes variations over time and with respect to its shape.
Induced magnetization depends on the magnetic susceptibility k of a rock
or mineral and the existing external field.

6
2
3. PLANET EARTH
• THE EARTH
Application: The magnetic method is the oldest geophysical prospecting

method applicable in oil prospecting, mining exploration and
archaeological artifacts.
In oil prospecting, the magnetic method provides information about the

depth of the rocks belonging to the basement. From this knowledge, it is
possible to locate and define the extent of the sedimentary basins located
above the basement, which possibly contain oil reserves.

6
3
3. PLANET EARTH
• THE EARTH
Magnetometers: There are several measurement methods and several
types of magnetometers, so a component of the magnetic field can be
measured.
The first method for determining the absolute horizontal intensity of the
geomagnetic field was developed by the German mathematician Carl
Friedrich Gauss (since 1831).
Magnetometers, which are based on mechanical principles, include the

inclination compass, the Hotchkiss supercompass, the Schmidt type
variometer, the compensation variometer.
The first magnetometer useful for mining prospecting was the Schmidt-
type variometer, which measures variations in the vertical intensity of the
magnetic field with an accuracy of 1g.
- INTRODUCTION TO GEOSCIENCES 6 59
4
3. PLANET EARTH
• THE EARTH
The 'flux-gate-magnetometer' is based on the principle of

electromagnetic induction and saturation and measures variations in the
vertical intensity of the magnetic field.
The nuclear magnetometer is based on the phenomenon of nuclear

magnetic resonance and measures the absolute total intensity of the
magnetic field at discrete times.
3. PLANET EARTH
• THE EARTH
GEOELECTRICITY:
They are based on the electrical conductivity or resistivity of rocks, which
are material properties. For example, sulfides have high conductivity/low
electrical resistivity, micas have very low conductivity, and porous rocks
saturated with water have high conductivity.
Measurements are performed with electrode configurations. In active

methods such as induced polarization, an electric current is generated
and the response of the rocks to this penetrating current is detected by
means of other electrodes.
Its reach with respect to depth depends on the length of the setup.

6
6
3. PLANET EARTH
• THE EARTH
Electrical methods are useful in determining the strength of strata of a
sequence of +/- horizontal sedimentary rocks. They are applied in the
search for aquifers or, that is, strata, which carry underground water, in
the search for sulfide deposits.
Geophysical logging: All the data collected in a well is compiled, along a

vertical section through the subsoil.
Diography geological : Geological, mineralogical and
structural of the different strata.
Geotechnical logging: Mechanical properties of the rocks in a well, such
as their degree of resistance, shear stress and the number of fractures
per unit volume.
Geophysical mapping : Includes nuclear, self-potential and seismic
measurements.
3. PLANET EARTH
• THE EARTH
Geophysical logging commonly provides multiple data obtained through a
single measurement process. These data include lithological, stratigraphic
and structural information, indicators of mineralogy and ore
concentration, and indicators for geophysical exploration from the
surface.
'Natural gamma ray log' or log of natural gamma rays: The dark
pelite zone gives a high response, the limestone and coal zones give
weak responses.
'Gamma gamma log' or density log detects the backscattered
rays (backscattered rays) of gamma rays emitted by a probe in
the well: Limestone and pelite are relatively dense rocks, coal is
relatively small in density.
Sonic log' or sound log (acoustic velocity) : It demonstrates the
contrast between the limestone and the less elastic strata such as - INTRODUCTION TO GEOSCIENCES

6
8
3. PLANET EARTH
• THE EARTH
'Neutron log' or neutron log : it uses a source that emits neutrons

and a corresponding detector: The differences in the water content are
presented, in this case coal has a high hydrogen index, limestone has a
low hydrogen index.
'Laterolog ' : It is a registered technique, introduced by the

SCHLUMBERGER service. Differences in the resistivity (or conductivity) of
the strata are detected: In the example, limestone and coal have low
conductivity, pelite has high conductivity.
3. PLANET EARTH
THE
EARTH
mm
mia
■
MM
MM
ERREMOTOS 'turn
:
P waves S waves
Superficial
S Wave Speed
I 24.5 km/sec
P Wave Speed
8 km/sec Focus or Hypocenter
at 20 km depth
UNI SANTANDER INDUSTRIAL

3. PLANET EARTH
• THE EARTH
EARTHQUAKES:
Due to tectonic forces: In some sectors of the world the Earth's crust
suffers tectonic forces that deform the rocks. Sometimes forces are
released in a break. These tectonic movements cause seismic waves that
feel like tremors on the Earth's surface.
Cause: Tectonic forces

elastic deformation

7
1
3. PLANET EARTH
• THE EARTH
EARTHQUAKES:
Due to the explosion of a volcano: This phenomenon can generate

seismic waves
Due to subsidence: Underground collapses generate tremors that are

strongly felt in nearby sectors. This often happens where there are karst
or salt deposits at depth.

7
2
3. PLANET EARTH
• THE EARTH
EARTHQUAKES:

7
3
3. PLANET EARTH
• THE EARTH
EARTHQUAKES
FOCUS AND EPICENTER
The focus or hypocenter of the earthquake is the place where the energy
is released. The epicenter is the projection to the surface.
The distance from the focus of an earthquake is reflected in the arrival of

the fast primary waves (p waves) and the slower secondary waves (s
waves). The time difference between the two (delta t) is large if the focus
is far away and vice versa.
The epicenter of an earthquake is determined: In observatories the
arrival time of the pys waves is detected, the initial time of the
earthquake can be calculated. For the observatories closest to the
epicenter (at least three), a circle is constructed with radius r = wave
speed p (os) start time. Three of these circles intersect at a single point,
which is the epicenter of the earthquake.

7
4
3. PLANET EARTH
THE EARTH
EARTHQUAK
ES
Most seismic energy is released at depths between 0 and 70 km (85%).

At a moderate depth of 70 to 300km, 12% of the seismic energy is
released. At a high depth between 300km and 700km, only 3% of the
seismic energy is generated. Earthquakes below 720km were never
detected.

7
5
4. PLANET EARTH
• THE EARTH
EARTHQUAKE:
INTENSITY
Relative scales (Intensities): The MERCALLI scale or the ROSSI-FOREL
scale, which are based on the destructions caused.

7
6
Rossi-Forel scale:
3. PLANET EARTH
• THE EARTH
EARTHQUAKE:
Absolute scales measure magnitude: RICHTER scale measures the

TA-h-nhE-h-
Description
mI*-- Intensity
Yo Registerable only by instruments
II Feeling for little people at rest
III Felt by several people at rest

IV Felt by several people in motion, movement of objects
V Generally felt by everyone, furniture movement

SAW General awakening of those who sleep
VII Overturning of moving objects, falling parts of walls
VIII Falling chimneys, cracks in the walls of buildings
IX Total or partial destruction of some buildings
x Great disaster, fissures in the earth's crust

7
7
energy during an earthquake in a logarithmic form.
3. PLANET EARTH
M = log10A/T + F(D,P) + constant, where:
• THE EARTHQUAKE
EARTHQUAKE:
A = maximum amplitude produced on the surface in micrometers, deduced from
Magnitude Atucha Time Dynamite Nuclear bomb
-3 10-3 Modern seismographs are sensitive to levels of -3.0.

the seismograph records. 0 - 175mg
-2 10-2 0.009 thousandth
T = period of the wave in seconds. 1

of
sec. 13g.
-1 10 -1
10- MF= = empirical

10-0.5 function
units of energy, for example,of
it isthe distance
the magnitude of D expressed in º and the depth P of the
8.56 thousandth of
0,5
0,5 focus expressed
energy
generated inofkilometers.
by the fall of a rock mass 100kg from a height of 2
sec.
0.89 kg.
10m above the earth's surface.
3 0.63 sec. 53 kg.
0 100 4 36.7 sec. 3 Ton.
1
1 10 5 27.5 min. 140 Ton.
The smallest earthquakes felt by humans are level 2 on the

2 102
RICHTER scale.
6 4.1 p.m. 6 Kilotons 0.3 Atomic Bombs
3
3 10
18 days 10.8
4 104 7
hours.
240 Kilotons 12 Atomic Bombs
5 105
6 106 0.3 Hydrogen

8 1 year 35 days 8.25 Megatons Bombs
7 107
8 108
8 ,5
8,5 10
In 1960 in Chile (first calculation) 9 18 years 90 days 250 Megatons
13 Bombs
Hydrogen
9, 5
9,5 10
Valdivia earthquake (1960) recalculated
-—
7
8
7
9
3. PLANET EARTH
• THE EARTH
EARTHQUAKE
:

8
0
3. PLANET EARTH
• THE EARTH
EARTHQUAKE:
THE SEISMOGRAPH
A seismograph records ground movements in both horizontal and vertical
directions. An ideal seismograph would be an instrument attached to a
fixed base, which is located outside the Earth. In this way, the vibrations
generated by ground movement could be measured through the variation
of the distance between the instrument held on the fixed base and the
ground.

8
1
3. PLANET EARTH
THE EARTH
EARTHQUAKE:
TSUNAMI
Tsunamis constitute a series of
waves with a period of time
ranging from waves from ten
minutes to one hour. They can
be generated by avalanches,
rashes
volcanic or seismic movements
originating from the ocean
floor. They spread through the
sea at an average speed of 800
km/hr.

8
2
3. PLANET EARTH
• THE EARTH
EARTHQUAKE
:
Rupture in the seabed ua upwards
The wave moves at a

speed of 500 km/h
The wave reaches ha 20 kn

decreases (45 km/h) but increases
the coast and
its height destroys everything
in its path
3. PLANET EARTH
• THE EARTH
EARTHQUAKE:
Tsunami degree m Wave height H (meters) Maximum flood level R (meters) Description of damage
0 1-2 1 - 1.5 Does not cause damage.
Flooded houses and destroyed

1 2-5 2-3 boats are swept away.
People, boats and houses are

2 5 - 10 4-6 swept away.
Damage widespread along the

3 10 - 20 8 - 12 coast.
Damage spread over more than

4 > 30 16 - 24 along the coastline.

3. PLANET EARTH
• THE EARTH
EARTHQUAKE:
INDIA HAILAND
• Westen com o' souther
Thonnd body aleeted, nouang
wutes of tm Nod. - rovone «> cao-t.,
Maom - and Apara Pradest mwetmthe INDIA Dhaka
Pnuawt anq P F nand
focerady admnatered tomtory ct
Ponachery Calcutta • MALAYSIA
odemtsanorecertodinte • Pwocle clipa 1» Nme been
skc« hay hem MwftM NON ms
BANGLADESI nortNm ety or Poang
Karau state
ANDHRA
PRADESH
BURMA LAOS
TAMIL • Madras Andaman^',

NADU I Let t
3
Pondsc
herty ° f K / :Y ( • GuH of. . ■ - 7 1 Thailand .
KERAL
A
Trineomaloe , Phuket 6,, ]
A.N.
Colombo
Mutur
*5 23' ' -.
SRI
LANKA
Pining
Mils
Epicenter of carthguake MALAYSIA
25 miles below seabed
7.59am local time
(0059 GMT)
MALDIVES
• Himh wincs and
2iod3 inunduta
• Twthrdeiw Mrgcopt
Mk, rt0ürtod to oc
tnder water

8
5
V 4.
• MINERAL MINERAL
UNIVERSITY I - DE SANTAN
INTRODUC GEOSCIENCE
4. MINERALOGY
• MINERALOGY
The geometric shape of a crystallized mineral is the external expression

of its internal molecular structure. The internal structure controls
many of the physical properties. All the properties of a mineral must
depend on the character of the elements from which it is derived.
compound.
INDUSTRIAL UNIVERSITY OF SANTANDER 8

7
4. MINERALOGY

8
8
4. MINERALOGY
• DEFINITIONS
MINERAL:
Minerals are natural and materially individual components of the rigid
crust.
They are naturally formed. Inorganic. Overall solid. They have a defined
chemical composition. Materially homogeneous. Crystalline (with an
ordered atomic structure) or amorphous (without a crystalline structure,
for example natural glass). Most minerals are crystals.
They may have been formed by inorganic processes or with the
collaboration of organisms, for example elemental sulfur, pyrite and other
sulfides can be formed by reduction with the collaboration of bacteria.
Sometimes minerals are part of organisms such as calcite, aragonite and
opal, skeletons or shells of microorganisms and invertebrates and apatite
can form.
8
9
4. MINERALOGY
• DEFINITIONS
CRYSTALS:
Crystals are often recognized for their beauty and symmetry. Crystals
have some properties:
Crystals are formed naturally.

Crystals have a unique atomic arrangement or arrangement of their
elements.
Natural crystals have characteristic degrees of symmetry which are a
consequence of the internal arrangement of the atoms that form them.
The crystals are:
Isotropic: Isotropic crystals have the same physical properties in all
directions as those of the cubic system, for example halite, pyrite.
Anisotropic: They have physical properties that are different in different
directions, for example cordierite, biotite, quartz.
- INTRODUCTION TO GEOSCIENCES.
9
0
4.MINERALOGY
4. MINERALOGY
• DEFINITIONS
Homogeneous: Minerals/crystals have the same physical properties in

parallel directions and have a defined and uniform chemical composition.
Crystalline: The different chemical components are found in defined

places and are arranged regularly, forming a crystal with a regular atomic
structure or an ordered atomic arrangement.
Amorphous: Without crystalline structure; Volcanic glasses and gel

precipitates (opal) are amorphous bodies.
• DEFINITIONS
Mineral: A naturally formed, materially homogeneous, solid chemical
element, a solid compound or a solid solution, for example calcite.
Crystal: A crystalline body with an ordered arrangement of its atoms, for
example quartz.
Rock: Rock is an aggregate of minerals of various grains and is rarely
natural glass (obsidian). It is formed by minerals or less commonly from a
single mineral.
The addition of minerals to rocks depends on their chemical composition
and the different conditions that prevailed during their genesis.
1. Composed of a single type of mineral: Monomineralic, for example:
limestone composed of calcite and pure sandstone composed of quartz.
2. Composed of several types of minerals: Polymineralic, for example
granite composed mainly of quartz, feldspar, mica and other minerals in
smaller quantities such as amphibole, apatite and zircon.
________ _____________" " 85

9
2
4.MINERALOGY
4. MINERALOGY
• DEFINITIONS
Soil: Material produced by weathering and the action of plants and

animals on rocks on the earth's surface.
Ore: Mineral from which a metal that is valuable can be obtained at a

cost at which it makes the work profitable. A homogeneous species of a
mineral which is used to extract one or more metals; with economic value,
which depends on the time and place of its formation.
4. MINERALOGY
• PHYSICAL PROPERTIES
MORPHOLOGY.
The combination of the faces of the mineral/crystal and the habit of the
mineral/crystal are distinguished.
Combination of the faces: The combination of the faces of the crystal
means the set of all the faces of the crystal or the crystalline form, which
depends on the symmetry of the crystal. Ex. Galenite PbS and halite NaCl,
which belong to the cubic system, can crystallize as cubes. In addition,
galenite can crystallize in a combination of cube and octahedron. Garnet
crystallizes in the rhombohedral form, in the isotetrahedral form, or in a
combination of these two forms. .
The faces of a crystal (habit): When crystals grow without

interference, they adopt shapes related to their internal structure. Habit
refers to the proportions of the faces of a crystal.

4. MINERALOGY
Habit:
Columnar: Elongated in one direction and similar to columns. Example:
corundum crystals.
Prismatic: Elongated in one direction. Example: andalusite crystals.
Tabular: Elongated in two directions. Example: barite crystals.

Lamellar: Elongated in one direction and with thin edges. Example:
crystals
of hornblende.

9
5
4. MINERALOGY
Habit:
Leafy: Similar to leaves, easily separated into leaves. Example: Muscovite.
Botroidal: Group of globular masses, for example group of spheroidal
masses of malachite.
Reniform: Radiating fibers, ending in rounded surfaces. Example:
hematite.
Granular: Formed by an aggregate of grains.

Massive: Compact, irregular, without any outstanding habit.

4. MINERALOGY
HARDNESS
The degree of resistance that a mineral opposes to mechanical deformation. A
useful, semiquantitative method was introduced by the German chemist Mohs with a
10-level hardness scale. For each level there is a representative and very common
mineral. The mineral of the upper level belonging to this scale can scratch all the
minerals of the lower levels of this scale.
Hardness Mineral Comparison
1 talcum powder The nail scratches it easily
2 And so The nail scratches it
3 Calcite The tip of a knife scratches it easily
4 Fluorite The tip of a knife scratches it
5 Apatite The tip of a knife scratches it with difficulty
6 Potassium Feldspar A piece of glass scratches it with difficulty
7 Quartz
It can scratch a piece of glass, causing the steel to spark.
8 Topaz
9 Corundum
10 Diamond

9
7
4. MINERALOGY
HARDNESS
The hardness of a mineral depends on its chemical composition and also on

the arrangement of its atoms. The greater the bonding forces, the greater
the hardness of the mineral.
Graphite and diamond, for example, have the same chemical composition,
they are only made up of carbon C atoms. Graphite has a MOHS hardness of
1, while diamond has a MOHS hardness of 10.

9
8
4. MINERALOGY
EXFOLIATION (Cruise)
Crystalline bodies can exfoliate on smooth surfaces along certain directions

under the influence of external mechanical forces, for example by pressure
or hammer blows.
This striking exfoliation (cruise) depends on the internal order existing in the
crystals. The exfoliation or cleavage planes are the consequence of the
internal arrangement of the atoms and represent the directions in which the
bonds that join the atoms are relatively weak. The exfoliation surface always
corresponds to simple crystalline faces.

9
9
4. MINERALOGY
EXFOLIATION (Cruise)
Complete exfoliation in 2 directions: Mica, chlorite, talc.

Good exfoliation in two directions: Potassium feldspar along two surfaces
perpendicular to each other, hornblende with prismatic exfoliation.
Good exfoliation in three directions: Calcite according to the rhombohedron.
Baryta.
Clear exfoliation in two directions : Pyroxene.
Unclear exfoliation : Olivine
Exfoliation absent : Quartz with its conchoidal fracture. In quartz the atoms
are arranged with such regularity that the bonds between them are very
similar in all directions.

1
0
4. MINERALOGY
GLOW
The shine is due to the mineral's ability to reflect incident light.
Glow Examples / Description

Metal pyrite, magnetite, hematite, graphite
semimetallic uraninite (pitchblende, UO 2 ), goethite
Vitreous quartz, olivine, nepheline, on crystal faces, siderite
Resinous such as resin, e.g. sphalerite.
Fatty greasy to the touch: quartz, greasy gray sheen nepheline.
Oily olivine.
Non-metallic Pearlescent such as the luster of pearls, e.g. talc, biotite, siderite
Silky
such as silk luster: fibrous structure gypsum, sericite, goethite
Mate like the shine of chalk
Adamantine brilliant: diamond, rutile

1
0
4. MINERALOGY
COLOR
Idiochromatic minerals: Minerals that have characteristic colors related to
their composition are called idiochromatic.
Mineral Color
Magnetite black
Hematite red
Epidote green
Chlorite green
lapis lazuli dark blue
Turquoise characteristic blue
Malachite Shining green
native copper copper red

1
0
4. MINERALOGY
COLOR
Allochromatic minerals: Minerals that present a range of colors depending
on the presence of impurities or inclusions are called allochromatic.
Potassium feldspar: whose color varies from colorless to white through
flesh-colored to intense red or even green.
Quartz: Pure quartz is colorless. The presence of several liquid inclusions
gives it a milky white color.
Amethyst: It has a characteristic purple color which is probably due to
impurities of Fe3+ and Ti3+ and radioactive irradiation.
Corundum: Pure corundum is colorless. Corundum carrying chromium as a
trace element is red in color and is called ruby.
Sapphire: It is a transparent variety of corundum of various colors.
Due to the existence of allochromatic minerals, color is a problematic means
of identifying a mineral.
1
0
3
4. MINERALOGY
COLOR
The color of the stripe : It is due to very finely ground pieces of crystal,
placed on a white base, such as a piece of porcelain, which makes it easier
to separate whether we are faced with a mineral of our own or another
color.
The color of the potassium feldspar stripe will always be white even if it is
produced by a colorless, flesh-colored or green potassium feldspar.
The color of the stripe is important in the identification of ores. The stripe
color of magnetite is black, of hematite is cherry red, of goethite is brown.

1
0
4. MINERALOGY
• OTHER PHYSICAL PROPERTIES
twinned crystals
Some crystals are made up of two or more parts in which the lattice
(Kristallgitter) has different orientations that are geometrically related.
Composite crystals of this type are known as twinned crystals.
Crystals composed of two individual parts, which have a defined structural

relationship, are called simple twins.
If the two parts of a simple twin are separated by a defined surface, it is
described as contact twinning.
Interpenetration twinning refers to crystals joined by an irregular plane of
composition - surface along which the two individuals are joined - for
example. orthoclase.

1
0
4. MINERALOGY
Solubility
Solubility depends on the composition of the mineral.
Above all, a cold dilution of hydrochloric acid HCl is used to distinguish
Calcite from pure CaCO 3 (calcium carbonate) from other similar minerals
with a smaller amount of CaCO 3 or without CaCO 3 .
Density
The specific weight of a mineral increases with the mass number of the
elements that constitute it and with the proximity or tightness in which they
are arranged in the crystalline structure.
Most rock-forming minerals have a specific gravity of about 2.7 g/cm 3 ,
although the average specific gravity of metallic minerals is about 5 g/cm 3 .
Heavy minerals are those with a specific gravity greater than 2.9 g/cm3, for
example zircon, pyrite, pyroxene, garnet.
1
- INTRODUCTION TO GEOC ENC AS
0
6
4. MINERALOGY
Magnetic and electrical properties
All minerals are affected by a magnetic field. Minerals that are slightly
attracted to a magnet are called paramagnetic, minerals that are slightly
repelled by a magnet are called diamagnetic.
Minerals have different capacities to conduct electrical current. Crystals of
native metals and many sulfides are good conductors, minerals such as
micas are good insulators since they do not conduct electricity.
Luminescence and fluorescence

Luminescence: The emission of light by a mineral is called, which is not the
result of incandescence. It is observed, among others, in minerals that
contain foreign ions called activators.

4. MINERALOGY
Fluorescence: Fluorescent minerals become luminescent when exposed to
the action of ultraviolet, X or cathodic rays. If the luminescence continues
after the excitation has been cut off, the phenomenon is called.
Intensely colored fluorites are phosphorescent minerals, which show
luminescence when exposed to ultraviolet rays.
Piezoelectricity
It is observed in minerals with polar axes (without a center of symmetry)
such as quartz, for example. Due to the polarity of the crystal structure
when energy, such as heat or pressure, is supplied to the mineral, an
electrical charge is generated at the two ends of the polar axis of a mineral.
Piezoelectric quartz is used, for example, in the piezoelectric geophone,
where a vertical movement of the Earth exerts pressure on a quartz crystal
and an electrical charge is produced. Another example is the "needle" of a
turntable.

4.
STRU
UNIVERSI TANDER
INTRODUCTION TO GEOSCIENCE
TY NCIAS 10
- YO
9
4. MINERAL
CRYSTALLINE STRUCTURES
CRYSTAL SYSTEMS: ...
Crystals are described by crystal systems
There are 7 crystalline systems one of them has his own

M _H _ n
and symmetry elements
1
write crystalline systems by
Its crystallographic axes.

The angles that two of the crystallographic axes surround
respectively
The lengths of the crist shafts cos
INDUSTRIAL DAD OF
SANTANDE DUCTION TO 103
GEOSCIENCES
4. MINERALOGY
• CRYSTALLINE STRUCTURES
CRYSTALLINE SYSTEMS:
Cubic system:
There are three crystallographic axes at 90° to each other: alpha = beta =
gamma = 90°
The lengths of the axes are equal: a = b = c
Typical shapes of the crystal system and its symmetry elements:

The cube (halite, fluorite), the rhombododecahedron (garnet) and the
octahedron (diamond, magnetite).
The Tetrahedron is a form with 4 ternary axes and 3 binary axes.

Sphalerite ZnS has a tetrahedral shape.

4. MINERALOGY
Tetragonal system:
There are 3 crystallographic axes at 90° to each other: alpha = beta =
gamma = 90°
The parameters of the horizontal axes are equal, but they are not equal to
the parameter of the vertical axis: a = b ≠ [is unequal to] c
Typical shapes and their symmetry elements are:
Zircon (ZrSiO2) belongs to the tetragonal system and forms p. e.g. prisms
limited by pyramids at the upper and lower ends.
Cassiterite SnO2

4. MINERALOGY
Hexagon system:
There are 4 crystallographic axes, three at 120° in the horizontal plane

and one vertical and perpendicular to them:
a1 = a2 = a3 ≠ c with a1, a2, a3 = horizontal axes and c = vertical axis.
Apatite Ca5[(F, OH, Cl)/(PO4)3] and graphite C belong to the hexagonal

system.
Typical forms are the hexagonal prism and the hexagonal trapezohedron
with one sexternary axis and 6 binary axes.

4. MINERALOGY
Trigonal system:
There are three crystallographic axes with equal parameters, the angles
X1, X2 and X3 between them differ at 90°:
X1 = X2 = X3 = 90°
a1 = a2 = a3
Calcite CaCO3 and Dolomite CaMg(CO3)2 belong to the trigonal system

and often form rhombohedrons.
Another form is a combination of trigonal and pinacoid pyramid with 3

binary axes of symmetry.

4. MINERALOGY
Orthorhombic system:
There are three crystallographic axes at 90° to each other:

alpha = beta = gamma = 90°
The parameters are unequal:

a ≠ b ≠ c [a is unequal to b is unequal to c]
Example: Olivine (Mg,Fe)2(SiO4)

4. MINERALOGY
Monoclinic system:
There are three crystallographic axes, of which two (one of the two is
always the vertical axis = c axis) are at 90° to each other:
alpha = gamma = 90° and beta is greater than 90°
The parameters are unequal.

Example: Mica

4. MINERALOGY
Triclinic system:
There are three crystallographic axes, none of them at 90° to each other:
alpha is unequal of beta is unequal of gamma is unequal of 90°
The parameters are unequal.

Example: Albite: NaAlSi308 and Disthene: Al2SiO5

4. MINERALOGY
CLASSIFICATION OF ROCK-FORMING MINERALS:
NATIVE ELEMENTS:
Native elements are the elements that appear without combining with the
atoms of other elements such as gold Au, silver Ag, copper Cu, sulfur S,
diamond C.
Apart from the class of native elements, minerals are classified according
to the character of the negative ion (anion) or group of anions, which are
combined with positive ions.
SULFIDES:
Including selenium compounds, arsenudes, tellurides, antimonides and
bismuth compounds.
Sulfides are distinguished based on their metal:sulfur ratio according to
the purpose of STRUNZ (1957, 1978).
11
4. MINERALOGY
Examples are galena PbS, sphalerite ZnS, pyrite
SANTANDER INDUSTRIAL AD
FeS2, chalcopyrite CuFeS2,
argentite Ag2S, Löllingit - ODUCTION TO GEOSCIENCES
UN IV
IN E
T R
R SI
O D
11
4. MINERALOGY
HALIDES
The characteristic anions are the halogens F, Cl, Br, J, which are combined
with relatively large cations of low valence.
Halite NaCl, sylvinite KCl, fluorite CaF2.
OXIDES AND HYDROXIDES

Oxides are compounds of metals with oxygen as an anion.
Cuprite Cu2O, corundum Al2O3, hematite Fe2O3, quartz SiO2, rutile TiO2,
magnetite Fe3O4.
Hydroxides are characterized by hydroxide ions (OH-) or H2O molecules.

Limonite FeOOH: goethite *-FeOOH, lepidocrocite *-FeOOH.

4. MINERALOGY
CARBONATES:
The anion is the carbonate radical (CO3)2-. Calcite CaCO3, dolomite
CaMg(CO3)2, malachite Cu2[(OH)2/CO3].
SULPHATES, WOLPHRAMATES, MOLYBDATES and CHROMATES

In sulfates the anion is the group (SO4)2- in which sulfur has a valency 6+,
for example in barite BaSO4, in gypsum CaSO4*2H2O.
In tungstates the anion is the tungstate group (WO4)4-, e.g.
scheelite or scheelite CaWO4.
PHOSPHATES, ARSENIATES AND VANADATE

In phosphates the anionic complex (PO4)3- is the main complex,
as in apatite Ca5[(F, Cl, OH)/PO4)3]arsenates contain
(AsO4)3- and vanadates contain (VO4)3- as an anionic complex.
4. MINERALOGY
SILICATES:
It is the most abundant group of rock-forming minerals where the anion is
formed by silicate groups of the (SiO4)4- type.
Silicates constitute:
25% of known minerals
90% of the earth's crust
For every 100 atoms in the crust:
62.5 are from O
21.2 are from Yes
6.5 are Al +3, Ca+2, Na+, Mg+2, Fe+2 and K+.
The Earth's crust is like a framework of structures formed by oxygen ions with
silicon and/or aluminum ions (in different arrangements) joined by small ions
of the type Ca+2, Na+, Mg+2, Fe+2 and K+.

4. MINERALOGY
THE STRUCTURE OF SILICATES
The structural principles of silicates are the following:
a) Each of the silicates has a tetrahedral complex ion as its basic compound.
This tetrahedron consists of a combination of a silicon ion, surrounded by 4
oxygen ions as closely as geometrically possible.
b) The basic unit of silicate structure is the [SiO4]4- tetrahedron. A few
structural types of silicates are distinguished: neso-, soro-, cyclo-, ino and
tectosilicates.
c) The Al3+ cation can be surrounded by 4 or 6 oxygen atoms (coordination
figure of 4 or 6). For this reason, it replaces Si4+ in the center of the
tetrahedron, for example in muscovite KAl[6]2[(OH)2/Si3Al[4]O11] or is
located in the center of an octahedron like the cations Mg2+ or Fe2+, for
example in sodium pyroxene Jadeite NaAl[6]Si2O6.

4. MINERALOGY

4. MINERALOGY
Nesosilicates formed from independent tetrahedra, which alternate with

positive metal ions, such as in olivine.

4. MINERALOGY
Sorosilicates formed from pairs of tetrahedra: [Si2O7], e.g. epidote

4. MINERALOGY
Cyclosilicates formed by rings of [SiO4]4- tetrahedra: [Si3O9]6-, [Si4O12]8-,

[Si6O18]12-, e.g. beryl Be3Al2[Si6O18].

4. MINERALOGY
Inosilicates formed by single chains or double chains of [SiO4]4- tetrahedra:

• by simple chains, for example pyroxenes
• by double chains for example amphiboles .

4. MINERALOGY
Phyllosilicates formed by plates of [SiO4]4 tetrahedra - for example kaolinite,

talc.

4. MINERALOGY
Silicates with three-dimensional tetrahedral structures , For example

feldspars and feldspathoids

4. MINERALOGY
CLASSIFICATION BASED ON THE EXTERNAL PROPERTIES OF
MINERALS.
This classification distinguishes:
The most common clear components are quartz, potassium, sodium and
calcium aluminosilicates such as potassium feldspar and plagioclases,
feldspathoids and muscovite. Other important light rock-forming minerals
are calcite CaCO3, dolomite CaMg(CO3)2, gypsum CaSO4*2H2O, anhydrite
CaSO4, apatite, zoisite, cordierite, talc, zeolite, clay minerals such as
montmorillonite and kaolinite and mica. illite. Clay minerals and illite are of
extraordinary importance in the sedimentary field and especially in soil
formation.
The most common dark components are iron and magnesium silicates
(mafic) such as olivine, pyroxene, amphibole, biotite, chlorite.
Typical minerals of metamorphic pargenesis are garnets and aluminum
silicates andalusite, sillimanite disthene (kyanite).

5. GEOLOGICAL dissolved
CYCLE mineral ")
precipitate
ufT sediments +,
transport and deposition
weathering and erosion compacting and cementing
(diagnese)
sedimentary rocks
sandstone
conglomerate
Andean little whistle
basalt magma folhelho
rhyolite (fusao) argilite
greywacke
calcareous
evaporites
gabbro chert
carvdo
diorite
granite
INDUSTRIAL UNIVERSITY OF SANTANDER grass, quartzite,
13
5. GEOLOGICAL
CYCLE
5. GEOLOGICAL Metamorphic rocks
CYCLE
Plutonic rocks volcanic rocks Sedimentary rocks
Minerals, Crystals, rock

fragments, fossils
Components crystals crystals and/or glass Crystals
Round-angular clasts
Component idiomorphic to Chemicals: idiomorphic to

idiomorphic to xenomorphic Mainly idiomorphic
Shape xenomorphic xenomorphic
Porphyritic texture (phenocrysts

Distribution of
float in an aphanitic mass)
grain sizes Porfidobastic texture
Equigranular Equi-Hetero granular
Microcrystalline
Macrocrystalline
Chemical sedimentary: in
Crystallinity Holocrystalline Hemicrystalline to hyaline holocrystalline
crystalline parts
(crystals only, no
glass)
Distribution of the Non-homogeneous,
Homogeneous Heterogeneous Stratification
components homogeneous
Foliation, Schistosity
Orientation of the
orientation
components Irregular fluid texture Clast orientation
always compact compact
Space occupation massive without gaps perhaps porous to foamy porous massive without gaps
Secondary factory
Other properties
fossils, HCl positive, flavor special minerals
Granite, Diorite, Gneiss, Schists,

Examples Rhyolite, Andesite, Basalt Limestone, Sandstone,
Gabbro Shale Marble
13
5. GEOLOGICAL
CYCLE
13
5. GEOLOGICAL
■ ROCK TEXTURE
CYCLE
'Fabric': Spatial arrangement of the components of a rock. Components
are groups of identical minerals or identical structural elements.
'Structure': Names phenomena such as folds, veins, joints, segregation
phenomena, etc.
In the books 'Physical Geology' by STRAHLER (1992) and LEET & JUDSON
(1968) texture refers to the English terms 'Texture' and 'fabric'. Texture is
derived from the Latin textus = fabric.
There are often very close relationships between the macroscopically
visible texture of a rock, its geological position and the place of its
formation.
Texture : Mode of construction of the rock, describes the relationships
between the components that build the rock. 'Texture' is determined by
the shape of the mineral components and by their geometric relationships.

6
5. GEOLOGICAL
CYCLE
ROCK TEXTURE: Grain shape
Ideomorph – Euhedric: The Hypidiomorphic – Subhedral:
edge of minerals is parallel to The edge of minerals is
crystalline faces sometimes parallel to crystalline
faces.
Photo:
Photo: hornblende on rock
Tourmaline
volcanic
7
5. GEOLOGICAL
■ ROCK TEXTURE : Grain shape
CYCLE
Xenomorph – Anhedric: Other terms to describe the shape of a mineral
are:
parallel to crystal faces
- Isometric: In all
directions of space +/-
regularly spread.
- Euhedral (the minerals show
some signs of crystals), cubic,
prismatic, columnar, notched
(stengelig), acicular (nadelig),
fibrous, tabular, leafy, scaly
(schuppig).
- Angular , rounded to various
degrees, ellipsoidal, globular is
Photo: Quartz in rock used for detrital grains of clastic
metamorphic. sedimentites.

8
5. GEOLOGICAL
■ ROCK TEXTURE
grain shape CYCLE
To describe the shape of the grain boundaries, terms such as:
Rectilinear, curved, arched, interrupted, amoebic in shape, toothed,

serrated, frayed, dendritic, skeletal.

9
5. GEOLOGICAL
■ ROCK TEXTURE
Granulity: CYCLE
The absolute dimension: For crystalline rocks the following classification
is used according to MATTHES (1987)
Grain diameter in mm Quantity of grains per cm²
Subdivision
> 33 <1
.
large grain 33-10 <1
coarse grain 10-3,3 1-10
medium grain 3,3-1,0 10-10²
small grain 1,0-0,3 10²-10³
fine grain 0,33-0,1 10³-10 4
dense, aphanitic 0,1-0,033 10 -10

4 6
Microcrystalline 0,033 - 0,001 > 10 6

0
5. GEOLOGICAL
CYCLE
■ ROCK TEXTURE
Granulity:
Porphyritic texture: Many vulcanites are characterized by a porphyritic

texture and present hiatal and irregular variation in grain sizes: Large
crystals (idiomorphic) float in a microcrystalline/cryptocrystalline mass.
The porphydoblastic texture: It is typical for many metamorphites. In

the case of metamorphites, the growth of one or another type of mineral
has been favored over the rest under physical or chemical conditions of
metamorphism.

1
5. GEOLOGICAL
■ ROCK TEXTURE
CYCLE
Crystallinity:
It is described by the degree to which the crystalline property is developed
and by the degree to which the rock is crystalline.
The degree to which the crystalline property is developed is

described by the sizes of the crystals and the following terms are used:
-Macrocrystalline, phanerocrystalline, phaneritic: The crystals/grains are
macroscopically visible.
■ Microcrystalline: The crystals/grains are visible through a microscope.
■ Cryptocrystalline: X-ray structural analysis must be carried out to verify
the crystallinity of the mineral components.
■ Aphanitic: Microcrystalline and cryptocrystalline (grain size
<0.001mm=1µm)
Amorphous: Without structure
INDUSTRIAL U NIVERSITY OF SANTANDER
14
5. GEOLOGICAL
- ROCK TEXTURE
CYCLE
Crystallinity:
The degree of crystallinity: It is described by the following terms:
- Holocrystalline: All the components that make up the rock are crystals,
for example granite, diorite and other plutonic rocks.
- Hemi-, hypocrystalline: The rock is made up of crystalline and
amorphous components such as rhyolite or dacite and other volcanic
rocks.
- Hyaline: All the components making up the rock are amorphous, for
example volcanic glass such as obsidian.

3
5. GEOLOGICAL
CYCLE
■ ROCK TEXTURE
Factory:
The spatial arrangement of the components building the rock is called. To
describe 'fabric' consider:
Component orientation:
Irregular orientation , isotropic rock, e.g. granite, diorite. Orientation of

components, anisotropic rock, e.g. micacite, phyllite. Orientation
according to the flow of magma or by strata of different textures or
mineralogical compositions. Lamellar and folded strata are distinguished.

4
5. GEOLOGICAL
CYCLE
■ ROCK TEXTURE
Factory:
The distribution of the components is described by the following terms:
Homogeneous: For example, a pure and dense limestone or a diorite
medium grain equigranular.
Not homogeneous:
The distribution of the components is influenced by the variation in the

size of the components (small variation = homogeneous rock, large
variation = non-homogeneous rock) and by the position of the
components.

5
5. GEOLOGICAL CYCLE
■ ROCK TEXTURE
Factory:
The occupation of space is described by the terms
Compact
Porous
Very closely porous structures are spread between vulcanites and

pyroclastics.
Porosity is also observed in sedimentites.
Porous rocks are many vulcanites and pyroclastics.
Compact rocks are especially plutonites and metamorphics.

5. GEOLOGICAL CYCLE
■ MINERAL AND ROCK RECOGNITION METHODS
Macroscopic Methods:
Macroscopic recognition is the simplest and most economical method. For
microscopic examination a special microscope is used and sample
preparation is mandatory. Chemical analyzes are carried out mainly by
special laboratories.

5. GEOLOGICAL CYCLE
■ METHODS FOR RECOGNITION OF MINERALS AND ROCKS
Only with your eyes and some tools you can describe a rock.
The tools are:

Magnifying glass, hammer, hydrochloric acid, a piece of porcelain.
With patience and experience you can reach very valid and profound
information.
It is described:
Texture, fabric, color, density, hardness, gloss, morphology, exfoliation
(fracturing), types of minerals, other properties.

5. GEOLOGICAL
CYCLE
METHODS OF MINERAL AND ROCK SURVEY Macroscopic
Methods:
1. Generalities:
1a) Color Overall color brown, yellow, two-tone white-

black...
1b) General Specific Weight light, normal, heavy

Weight
irregular, regular, lamellar, cubic

1c) fracturing How the rock breaks
smooth, rough surface
1d) overall soft, normal, hard

hardness hardness

9
5. GEOLOGICAL
CYCLE
■ METHODS FOR RECOGNITION OF MINERALS AND ROCKS
2. Texture/structure
macrocrystalline / phaneritic microcrystalline / aphaneritic
cryptocrystalline
size, visibility of crystals amorphous

2a) crystallinity: (components) hyaline
very large grain large grain
2 a1) Absolute grain size size in mm medium grain compact fine grain
equigranular
all the same or are there different irregular heterogranular (porphyritic texture)
2b) size distribution diameters
idiomorphic
magnitude of the "original" xenomorph hipidiomorph

2c) shape of crystals / grains crystalline form of the components
holocrystalline
2d) Magnitude of crystallization crystal or glass? hemicrystalline
amorphous - hyaline
141
5. GEOLOGICAL
CYCLE
5. GEOLOGICAL
METHODS CYCLE
OF MINERAL AND ROCK SURVEY Macroscopic
Methods:
isotropic (without orientation)
3a) component orientation with/without preferred orientation anisotropic: stratiform, fluid, schistose,
folded,
compact
3b) occupation of space porosity
porous: pumitic, foamy, spherolytic
normal, regular
3c) Component limits Analysis of the set altered
soldiers
crystals
3d) Types of grains crystals or fragments fragments: minerals, rocks: clastic
texture
primary component secondary component

4) Minerals components: modal content Special minerals

2
5. GEOLOGICAL
■ METHODSCYCLE
FOR RECOGNIZING MINERALS AND ROCKS
Microscopic Methods:

3
5. GEOLOGICAL
■ MINERAL AND
CYCLE
ROCK RECOGNITION METHODS
Geochemical Methods:
X-ray fluorescence: Allows analysis by chemical elements. The result is a
list of the main chemical elements in % (SiO2, Al2O3, FeO, MgO, ...), the
trace elements in ppm (Ba, Sr, U, Cu, ...) and the rare earths ( And, Nb..).
Diffractometry: As a result, lists of the contents in

sample minerals. Sometimes a semi-quantitative analysis can be done. All
minerals with a crystalline structure can be detected with this method,
clay minerals.
especially diffractometry is applied for the
INDUSTRIAL UNIVERSITY OF SANTANDER 15
5. GEOLOGICAL
CYCLE
15
6. IGNEOUS ROCKS
• HE
CIE
6. IGNEOUS ROCKS
• THE MAGMA
Mixture of chemical components that form high-temperature silicates,

normally includes substances in solid, liquid and gaseous states due to the
temperature of the magma that is above the melting points of certain
components of the magma. In this molten mixture the metal ions move
more or less freely.
In most magmas, some crystals that form during the previous phases of
magma cooling are suspended in the molten mixture. A high proportion of
suspended crystals and liquid material gives magma some of the physical
properties of a solid. In addition to liquids and solids, magma contains
various gases dissolved in it.

8
6. IGNEOUS ROCKS
• THE MAGMA
Pressure plays an important role in the formation of magma. At high
pressure the crystallization temperatures of minerals are also high. A
decrease in pressure consequently results in a decrease in the melting or
crystallization temperature of the minerals. In this way, at high depths in
the Earth's crust and in the upper mantle, magma can be produced from
solid material.
We compare the solid rock material located at high depths, that is, in the
upper mantle, with a volume of water enclosed in a pressure cooker,
boiling, for example, at a temperature of T = 120°C. How does water turn
into steam? Or is it how rocky material turns into magma? There are two
possibilities:
1. You can intensify the heat or increase the temperature until the water is
boiling.
2. You can open the pressure cooker or, in other words, reduce the
pressure, the water will come out of the pot in explosive and gaseous form.
In the case of the rocky material located in the upper mantle the decrease
,
in pressure (the probability for the foundry - INTRODUCTION TO GEOSCIENCES 148

of rock material and the generation of magma
6. IGNEOUS ROCKS
• THE MAGMA
Wash: It is called the portion of the magma, which appears on the surface
terrestrial and that comes into contact with air or water respectively. The
lava cools quickly.
Volatiles: They are liquid and gaseous chemical substances that maintain
the liquid or gaseous state at a temperature (melting or condensation
temperature respectively) lower than that of silicates characterized by
relatively high melting temperatures.
Magma contains, among others, the following volatile components:

Water as dissolved gas: 0.5 - 8% of magma and 90% of all volatiles.
Carbon in the form of CO2, Sulfur S2, Nitrogen N2, Argon Ar, Chloride Cl2,
Fluorine F2 and Hydrogen H2.

1
6. IGNEOUS ROCKS
• THE MAGMA
Geothermal gradient: The rise in temperature with depth is on average 1°/30m or
30°/1km. In a subduction zone along the sinking plate the geothermal gradient is
lower, approximately 5°C to 10°C/1km. In a magmatic arc the geothermal gradient
is greater and can reach 90° to 100°/km.
Each mineral has its own melting temperature for defined conditions (such
as pressure, chemical composition).
Pressure in Corresponding depth in Melting
mineral or rock Structural formula temperature Tf in
kbar km
°C
Olivine(Mg, Fe)2SiO4 0.001 (= 1 bar) 0 1600-1800
AnorthiteCaAl2Si208 0,001 0 1200-1400
ironFaith 0,001 0 1500
ironFaith 40 100 1650
60% pyroxene, 40%
dry basic rock 8 20 1360-1400
anorthite
Basic rock with a
60% pyroxene, 40%
substantial proportion of 8 20 700-1000
anorthite, water
water
6. IGNEOUS ROCKS
• TYPE OF ROCKS
Igneous or magmatic rocks

Intrusive rocks or Subvolcanic or Extrusive or
Volcanoclastic rocks
plutonic rocks hypabyssal rocks volcanic rocks
Crystallization at shallow Surface crystallization or in the
Crystallization at high depths Crystallization to the surface
depths atmosphere
slow cooling medium cooling rapid cooling very fast cooling
small crystals and perhaps
large crystals large or small crystals small crystals
phenocrysts
no amorphous minerals almost no amorphous with amorphous minerals with amorphous minerals
minerals
no porosity almost no porosity with porosity maybe foamy texture
equigranular or porphyritic fine grain or porphyritic
equigranular texture fine grain with bombs or clasts
texture texture
hypidiomorphic crystals
hypidiomorphic crystals or/and idiomorphic idiomorphic phenocrysts crystals with fused contours
phenocrysts.

6. IGNEOUS ROCKS
• ORIGIN OF IGNEOUS ROCKS
rock
s
hypa
byss
al
rock
s
intm
usM
as
(sub
olca
nico)
volc
anic
UNIVERSITY - NDER
INTRODU GEOSCIENCES 16
4
6. IGNEOUS ROCKS
DIFFERENTIATION BY CRYSTALLIZATION
Differentiation : formation of partial magmas of different

compositions.
Fractionation : separation of crystallized minerals from the remaining

magma by gravitation for example.
From the magma, silicate crystals are formed successively when the
temperature of the magma reaches the typical melting temperature for each
type of crystal. The first crystals formed later may change their composition
or may dissolve again. Since several successive reactions occur as the
temperature of the magma decreases, the ordered series of reactions is
called the BOWEN series in honor of the American scientist who formulated
this concept. There are two types of reactions, the continuous reaction and
the
6. IGNEOUS ROCKS
discontinuous. - INTRODUCTION TO GEOSCIENCES 154
6. IGNEOUS ROCKS
The formation of partial magmas is explained by
a) Gravitational differentiation
b) BOWEN's reaction principle (left):
The reactions of early crystallized minerals with the remaining magma can
essentially be described with the following two simple model systems:
Forsterite (Mg 2 SiO 4 ) - SiO 2 suitable for mafic minerals such as olivine
and pyroxene:
Olivine crystallization -->
partial separation of the remaining magma by gravitation (accumulation of
olivine at the bottom of the magma chamber) or by the formation of a
EnuU00s p r_-... r-!|jÜr.-LUüjJ.J14 úijü:.:
pyroxene aureole around the olivine, which functions as a protective shield

preventing the olivine from reacting with the magma -- >
Remaining magma enriched in SiO 2 and Fe 2+ , poorer in MgO compared
to the original magma -->
temperature drop -->
formation of (Mg, Fe) pyroxene -->
(Mg, Fe) Ca-pyroxene --> hornblende --> biotite. Minerals crystallized
relatively late such as hornblende and pyroxene incorporate OH groups in
their structure.
IAL DE SANTANDER AS GEOSCIENCIAS
Fig. Bowen reaction series
16
7
6. IGNEOUS ROCKS
SANTANDER IAL
AS GEOSCIENCES
16
8
6. IGNEOUS ROCKS
CLASSIFICATION OF THE MAGMATIC SEQUENCE

6. IGNEOUS ROCKS
• CLASSIFICATION OF MAGMATIC ROCKS
Most of the Earth's magmatic rocks are made up of more than 90% by
weight of silicate minerals and quartz or only silicate minerals. In a small
percentage by weight, Fe and Ti oxides may participate, in a lower
percentage by weight, calcium phosphate and other minerals may be
present.
In general, the composition of magmatic rocks can be presented

completely or almost completely by their content in the following oxides:
SiO2, TiO2, Al2O3, Fe(3+)2O3, Fe(2+)O, MnO, CaO, Na2O, K2O, P2O5,
CO2, SO3 and H2O.
Typically SiO2 is the dominant component.

0
6. IGNEOUS ROCKS
CLASSIFICATION BY SIO2 CONTENT
A simple classification of magmatics is based on their content in

SiO2:
acidic magma: intermediate

>65% SiO:
magmatite:
65-52% SiO,
basic tita magma: 52-45% SiO,
ma gm atita su ltr aba si ca s: <45% desi0.
17
1
6. IGNEOUS ROCKS
17
2
6. IGNEOUS ROCKS
STRECKEISEN DIAGRAM (DOUBLE STRECKEISEN TRIANGLE)
GUMS
6. IGNEOUS ROCKS
• CLASSIFICATION OF MAGMATIC ROCKS STRECKEISEN DIAGRAM
(DOUBLE STRECKEISEN TRIANGLE)
Its modal mineral content must be known. Simple methods to determine it are the
following:
+The qualitative content of the rock is determined by identifying all the
microscopically visible minerals and the participation of each type of mineral is
estimated.
+The qualitative content of the rock is determined by observing a transparent
section of the rock in question through a micropolariscope,
The four parameters of the double Streckeisen triangle are:

Q = Quartz and other SiO2 minerals.
A = Alkali feldspar (potassium feldspar including perthite and albite).
P = Plagioclase (An 5 to 100), scapolite.
F = Feldespathoids: leucite, calsilite, nepheline, sodalite, haugin, cancrinite,
analcime and the transformation products of these minerals.

6. IGNEOUS ROCKS
STRECKEISEN DIAGRAM (DOUBLE TRIANGLE OF
STRECKEISEN)
The field problem 9 and 10 (Andesite-Basalt/Diorite-Gabbro)
Diorites/andesites and gabbros/basalts fall in the same field (field10) of
the double Streckeisen triangle. Almost the only clear component of what
they are made of is plagioclase.

6. IGNEOUS ROCKS
STRECKEISEN DIAGRAM (DOUBLE TRIANGLE OF
STRECKEISEN)

6. IGNEOUS ROCKS

6. IGNEOUS ROCKS
• CLASSIFICATION OF MAGMATIC ROCKS STRECKEISEN DIAGRAM
(DOUBLE TRIANGLE OF
STRECKEISEN)

9
6.6.IGNEOUS ROCKS
IGNEOUS ROCKS
AMORPHOUS MINERAL CONTENT: In the case of vulcanites

Additionally, its glass content can be indicated as follows:
0 - 20% volume: carrying glass.
20 - 50% volume: rich in glass.
50 - 100% volume: glassy.
Acidic, glassy vulcanites with a volume percentage greater than 80% are
called obsidian or 'Pechstein'.

MAFIC MINERALS:
Mafic minerals do not occur in the double Streckeisen triangle. Mafic

minerals are Fe and Mg micas, amphiboles and pyroxenes, olivine, ores,
zircon, apatite, titanite, epidote, orthite, garnet, melilite, monticelite and
primary carbonates.
According to its composition, muscovite does not belong to the mafic

minerals, but it does not belong to components A, P, Q and F either.
Mafic minerals are determined by their participation in the magmatic rock

in question. If its participation is less than 90% (color index M < 90), the
double Streckeisen triangle is used. If its participation is greater than 90%
(M > 90), it is an ultrabasic rock, which is classified through other

1
6. IGNEOUS ROCKS
diagrams.

6. IGNEOUS ROCKS
MAFINAL MINERALS: A classification can be used

supplementary based on its color index using the prefixes
following:
Perid otite Pyroxenite

Diagram of classification based on Olivine contents-
Pyroxenes. For m>90%: Mafic mineral content greater than 90

3
•
6. IGNEOUS ROCKS
CLASSIFICATION OF MAGMATIC ROCKS
DIKES AND SUBVOLCANIC ROCKS (HYPABYSALS)
The nomenclature for dikes and subvolcanic rocks is not uniformly
practiced, but there is a tendency to bring it closer to the nomenclature of
plutonic rocks.
A name is chosen, which also indicates special properties of its texture, for
example a dyke or a subvolcanic rock of granitic composition is called
microgranite or a dyke with inclusions of feldspar and/or quartz in a dense
mass or is called porphyritic microgranite. very fine grained.
a) According to STRECKEISEN for intrusive rocks:

b) Special names: Pegmatite / Aplite / Lamprophydes

6. IGNEOUS ROCKS
PYROCLASTS
Uncompacted material is called tephra, regardless of the composition or
grain size. The different fragments, loose or compacted, are called
pyroclasts.
Due to erosion processes, ashes and tuffs can be transported and

agglomerated with pelitic material, forming tuffites or tuffitic sediments.
SANTANDER
SCIENCES
6. IGNEOUS ROCKS
PYROCLASTS
Pumice: They are porous pyroclastics, which are made of glass in foam
form and are formed during a very rapid cooling of a high-viscosity
ascending magma. Characteristic of clear and acidic vulcanites, such as
rhyolite, and therefore they are grayish white to yellowish in color, rarely
brown or gray. Fresh pumice stones have a silky shine. They are made of
glass fibers braided and twisted around gaps and inclusions.
Ignimbrites: They are sedimentations of ash streams, they are of poor

selection, of irregular relative size of components, heterogeneously,
porous. Many ignimbrites are parallel in texture due to flattened glass
formations with diameters up to 10cm.

6. IGNEOUS ROCKS
• CLASSIFICATION OF MAGMATIC ROCKS HYPOABYSAL OR
SUBVOLCANIC ROCKS (DYkes)
The Dykes: Magmatic tabular structures with a thickness between 0.5m

and 200m. In most these bodies are sub-vertical.

6. IGNEOUS ROCKS

6. IGNEOUS ROCKS
HYPOABYSSAL OR SUBVOLCANIC ROCKS (DIES)
TEXTURE OF HYPABYSSAL ROCKS
They have a texture similar to an intrusive or volcanic rock:
a) Equigranular texture, medium grain, but the size of the crystals is
smaller.
b) Porphyritic texture with larger crystals in the mass as in a common
volcanic rock.
DENOMINATION:
a) According to STRECKEISEN for intrusive rocks:
b) Special names: Pegmatite or Aplite
Porphyry granite: Dike with Quartz, Alkaline Feldspars and Plagioclase
with a porphyritic texture.
Microdiorite: Dike with Plagioclase, but with small crystals.
Pegmatite: Normally dark dyke with very large crystals (10 cm-1m) of
minerals and very scarce chemical elements.
6. IGNEOUS ROCKS
6. IGNEOUS ROCKS
VOLCANIC ROCKS (EXTRUSIVE)
Solidification forms of vulcanites are closely related to their SiO2 content,

to the gas content of the respective melts and to the viscosity of the lava.
Magmas or lavas with a high SiO2 content are of high viscosity, that is,
they are relatively little liquid, magmas or lavas with a low SiO2 content
are of low viscosity, that is, they are relatively liquid. The surfaces of
basaltic lava flows, which are low viscosity (very liquid), show
characteristic welding patterns. The names of these forms of welding
have been derived from the aboriginal languages of Hawaii, for example
cordate lavas are called 'Aa and Pahoehoe Lava'. If a lava flow flows into
a lake or into the interior of a sea (on underwater sea ridges, for
example), pillow lavas are formed, which are basaltic in composition.

6. IGNEOUS ROCKS
The lava
Properties of lava are the following:
Temperature (T), Explosivity, Viscosity.
Low viscosity = Melted, similar to a mixture of milk and sugar for making candy at
low T.
High viscosity = Sticky, similar to the same mixture of milk and sugar, which was
boiled for several minutes and cooled and has become a thick mixture.
Basic lava: Emerges with T = 1000 - 1200°C. Low viscosity due to its low content
of Si-O tetrahedra. It moves rapidly along gently sloping surfaces such as gently
sloping hillsides, often spreading in thin sheets. Low volatile content.
Acid lava: Emerges with T = 800 - 1000°C. High viscosity, which is why it flows
slowly and solidifies relatively close to the place from which it emerges. Highly
explosive due to its high volatile content
6. IGNEOUS ROCKS
Andesite is mainly composed of plagioclase, hornblende, biotita

and augite. It frequently shows a porphyritic texture with
plagioclase phenocrysts. The matrix is dense and microchrysaline
of black, gray, gray-green, reddish-brown. The phenocrysts are
idiomorphic to hypoidiomorphic, up to one centimeter in size.
Micro/crypt or crystalline texture^ almost without phenocrysts.

Plagiarism of asa, phoid, augite, amphibole, olivine, magnetite
and apatite. Normally black or greenish-black in color.
6. IGNEOUS ROCKS
• CLASSIFICATION OF MAGMATIC ROCKS VOLCANIC ROCKS
(EXTRUSIVE)
SANTANDER IAL
THE GEOSCIENCES 19
4
6. IGNEOUS ROCKS
VOLCANOCLASSIC / PYROCLASSIC ROCKS
In the case of explosive volcanic activity, the cooled magma fragments
and is expelled and distributed in the form of loose material. This material
expelled, fragmented and distributed by the wind, not compacted, is called
tephra, regardless of the composition or size of the grains. The different
fragments, loose or compacted, are called pyroclasts.
6. IGNEOUS ROCKS
Volcanoclastic rocks are those with clastic texture caused by volcanic
processes. Explosive volcanic eruptions, for example, produce large
volumes of volcaniclastic detrital material.
Blocks are called angular clasts produced by the fragmentation of solid

rocks. Bombs originate from expelled pieces of magma, transported by the
wind and shaped by their solidification in the air resulting in aerodynamic
bodies.
In addition to the classification according to size, volcanic fragments can

be distinguished based on their composition:
Vitreous - Crystalline - Lithic (That is, fragments of polygranular rocks)
' Ash ' grain size clasts are usually glassy or crystalline, blocks occasionally
glassy.
6. IGNEOUS ROCKS
Denomination:
By size :
Fragment size pyroclastic (compacted)
Tephra (no compaction)
> 64mm bombs pyroclastic
2 - 64mm lapilli lapilli tuff
< 2mm ash ash tuff, ignimbrite
Special names: Such as Ignimbrite, Liparite, Pumice Stone

The inheritance of volcanic fragments . The clasts involved and
coming from the volcanic event are called juvenile clasts. The clasts
formed by tentative and incorporated fragments are -
accidental clasts.
6. IGNEOUS ROCKS
INTRODUCTION TO GEOSCIENCES 179
6. IGNEOUS ROCKS
Pumitas: They are porous, pumitic pyroclasts, with a silky shine, that swim
on the water surface. They are made up of subparallel braided glass fibers
twisted around gaps and inclusions. In this way the rock resembles foam.
They form during a very rapid cooling of a high-viscosity ascending
magma. Pumice is used as a lightweight construction rock and as a
thermal insulator.
6. IGNEOUS ROCKS
6. IGNEOUS ROCKS
Pumice: They are porous pyroclasts, which are made of glass in foam
form and are formed during a very rapid cooling of a high-viscosity
ascending magma. These are very characteristic of light and acidic
vulcanites and are therefore grayish white to yellowish in color, rarely
brown or gray. Fresh pumice stones have a silky shine.
20
1
6. IGNEOUS ROCKS
Ignimbrites: These are sedimentations of currents of material expelled
from the volcano (fiery avalanches). They are made of ash, lapilli and
blocks. The components are welded together. They can be called tuffitic
breccias of volcanic material of all grain sizes (ash, lapilli, blocks). They
are of poor selection or, that is, of irregular distribution of grain sizes,
heterogeneous and porous.
IVERS L DE
- INITD
- II * II— S
GEOCIENCE
6. IGNEOUS ROCKS
GEOCHEMISTRY
The application of micro- or macroscopic methods to dense, very fine-
grained or fine-grained volcanic rocks becomes difficult. So that the same
classification method can be applied as in the case of plutonites, the
potential mineral content can be calculated based on a chemical analysis
(e.g. Rittmann standard, CIPW standard). Regarding their mineral
content, volcanic rocks are equivalent to different plutonites, as illustrated
by the double Streckeisen triangle. When classifying a vulcanite based on
its chemical analysis, a satisfactory match is sought with the analysis of a
plutonite and the vulcanite is named according to the names presented by
the double Streckeisen triangle for vulcanites.
Apart from this, there is other terminology for vulcanites, especially for
basalts and andesites, which is mainly based on the results of the CIPW
standard, on the distribution of different elements and on the proportions
of different elements.
20
3
6. IGNEOUS ROCKS
GEOCHEMISTRY
Classification by Sodium and Potassium vs SiO2
This diagram allows a classification of
intrusive rocks by means of sodium,
potassium versus silica contents.
Furthermore, a distinction is made between
"subalcalic" and "alcalic".
50 52.5 55 JO 57.5 ÓEJO 62.5 650 675 70.0 725 75.0 77 5 80.0
Name
in %ofweight Yes02
intrusive rocks according to COXetal. (1 979)
Alcalicisubalcalic limit according to MIYASHIRO (1970).
WG98
Geoche01 .cdr
20
4
6. IGNEOUS ROCKS
OF SANTANDER
GEOSCIENCES
20
5
6. IGNEOUS ROCKS
GEOCHEMISTRY
Classification by Potassium vs SiO2
A potassium versus silica classification is
sometimes used. We speak of high-K,
which means a relatively high potassium
content.
Equivalent is medium and low - K, for
lower values.
L DE SANTANDER
GEOSCIENCES

Introduction To Geosciences 1

Uploaded by

Copyright:

Available Formats

Introduction To Geosciences 1

Uploaded by

Document Information

Original Description:

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Introduction To Geosciences 1

Uploaded by

Copyright:

Available Formats

INTRODUCTION TO GEOSCIENCES

Earth Sciences or Geosciences, like other sciences, are

Until the 19th century, the Earth sciences were

Earth Sciences are not only knowledge of something

INDUSTRIAL UNIVERSITY OF SANTANDER - INTRODUCTION TO GEOSCIENCES 2

Grouping of sciences or disciplines that study the

INDUSTRIAL UNIVERSITY OF SANTANDER - INTRODUCTION TO GEOSCIENCES 3

INDUSTRIAL UNIVERSITY OF SANTANDER - INTRODUCTION TO GEOSCIENCES 5

Geophysics: Study of the physics of the earth, gravity anomalies,

INDUSTRIAL UNIVERSITY OF SANTANDER - INTRODUCTION TO GEOSCIENCES

INDUSTRIAL UNIVERSITY OF SANTANDER - INTRODUCTION TO GEOSCIENCES

INDUSTRIAL UNIVERSITY OF SANTANDER - INTRODUCTION TO GEOSCIENCES 1

Geo. Javier Enrique Peña Manosalva

XENOPHANES (600 years before Christ ): Fossils were animals

INDUSTRIAL UNIVERSITY OF SANTANDER - INTRODUCTION TO GEOSCIENCES

LEONARDO DA VINCI ( 1452-1519) : He described fossilization,

SMITH, William (1769-1839): Second geological law: Each

INDUSTRIAL UNIVERSITY OF SANTANDER - INTRODUCTION TO GEOSCIENCES

Until 1906 : Geotectonic theories : theory of the expansion of the earth,

INDUSTRIAL UNIVERSITY OF SANTANDER - INTRODUCTION TO GEOSCIENCES

Age 20 billion years

INDUSTRIAL UNIVERSITY OF SANTANDER

INDUSTRIAL UNIVERSITY OF SANTANDER

• A "curved" 3-dimensional universe is finite but for human

• The universe is expanding

INDUSTRIAL UNIVERSITY OF SANTANDER

INDUSTRIAL UNIVERSITY OF SANTANDER

INDUSTRIAL UNIVERSITY OF SANTANDER

Universe m The earth

INDUSTRIAL UNIVERSITY OF SANTANDER

Distance from the

Land 149 12.756 5,52 N2,O2

INDUSTRIAL UNIVERSITY OF SANTANDER

SANTANDER INDUSTRIAL ERSITY

INDUSTRIAL UNIVERSITY OF SANTANDER

THE MOON AND THE

INDUSTRIAL UNIVERSITY OF SANTANDER

FORMATION OF THE MOON:

Meteoroids: Most of their particles are extremely tiny, they vaporize

Hexahedrite: NEUMANN lines, they appear when corroding a polished surface.

Rocky or stony meteorite (aerolite): Silicate minerals mainly of olivine

Fero-rocky meteorite (siderolite): Consisting of a heterogeneous

Fero-rocky meteorite 1,5 % Yes, Nor, Faith

Equatorial radius: 6378 km

Age: 4.65 billion years

INDUSTRIAL UNIVERSITY OF SANTANDER

Surface of the Low depth sea deep sea

INDUSTRIAL UNIVERSITY OF SANTANDER

Only the method by measuring the radioactive decay of some isotopes

INDUSTRIAL UNIVERSITY OF SANTANDER

INDUSTRIAL UNIVERSITY OF SANTANDER

0-40km: Continental crust is divided by the Conrad discontinuity, which is

Moho discontinuity is the division between crust and mantle.

INDUSTRIAL UNIVERSITY OF SANTANDER

up to 700km: Upper mantle of a solid, rigid lithosphere and an

700 - 2900km : Lower mantle

Gutenberg discontinuity is the division between mantle and core

2900 - 4980km : Liquid iron outer core