Foliation and lineation

Presented To:
Mr. Abdul Hannan (lecturer)
Presented By:
Amir Hamza BGLF13M034
Danish Qamar BGLF14M044
Dpt. Earth Sciences.
University of Sargodha, punjab,
Pakistan

A general understand of
foliations and lineations,
before the complete
brief on foliations and
lineations sepreately……

Foliation
 “ word foliation derived
from latin word folium
which means leaf”
 Homogeneous
distributed planner
structure in the roks
 i.e: planner feature

Lineation
 Homogeneous
distributed linear
structure
 i.e: linear structure

Primary Foliation and
Lineation
 Foliations and lineations are primary if they were
origenated by primary sedimentary and igneous
process
 i.e: for sedimentary rocks,foliation and lineation
forms during deposition and transportation before
compaction. And for igneous rocks foliation and
lineation forms during the crystallization of magma
in preferred orientation.

Secondary Foliation and
Lineation
 Foliations and lineations are secondary if they
were originate by secondary process.
 Such as during tectonic activity/ deformation
or during the Metamorphism.

Tectonics
L-tectonics
 Linear preferred
orientation.
S-tectonics
 Planner preffered
orientation.

Significance of foliations and
lineations
 If foliations and lineations can be
distinguished from one another by type,
by cross-cutting relationships, absolute
age and by microsope,
 Then we can help to study of tectonic
and metamorphic evolution of area.

Now, we well dicussed
Fliation and Lineation in
further details as well as
the types of each…..

Types of Foliations
1.Spaced Foliations
a) compostional
b) disjunctive
c) crenulation
2.Contineous Foliations
a) fine
b) coarse

Compostional Foliations
 Compostional foliations are marked by
the layers or lamina of different
mineralogical compostion.
 A planer alignment of platey or niddle
like crystals may be present.
 Compostional foliations are subdivided
into…

Compostional Foliations
a. Diffused
Characterised by,
 Widely spaced
 Weak concentrations of
minerals predomently
of single lithology
 Common in Ulta-Mafic
rocks
b. Banded
Characterised by,
 Relatively closed spaced
Compostional layers
 Minerologically distinct and
of compare-able
abundance
 Common in high grade
metamorphic gneisses.

Disjunctive Foliations
 Disjunctive word derived from Disjunctus a Latin word which
means disjoined.
 A foliation that is formed in sedimentary rocks that have been
subjected to tectonic differential stress under sub-greenschist
metamorphic conditions.
 It is defined by array of subparallel fabric elements called cleavage
domains, in which the original rock fabric and compostion have
beeb markedly changed by the process of pressure solution.
 The domains are separated from one another by intervels, called
microlithons in which the original rock is preserved.

Disjunctive foliations
(Cleavage domains)

On the basis of smoothness or regularity of
cleavage domains we further divided disjunctive
foliations into four groups.
A. Stylolitic
B. Anastomosing
C. Rough
D. Smooth

Stylolitic disjunctive foliations
 Cleavage domains are long, continuous
but very irregular
 This type of foliations is typically in
limestone in which cleavage domains
are characteristically are thin, dark, clay
seams.

Anastomosing disjunctive
foliations
 Cleavage domains are long, continuous,
wavey forming an irregular network
outlining lenticular microlithons
 Such foliations are common in limestone
and in phyllites and schists.

Rough disjunctive foliations
 Cleavage domains are short,
discontinuous concentrations of highly
oriented platey minerals.
 Typically abundant in rocks containing
sand sized minerals.

Smooth disjunctive
foliations
 Cleavage domains are long, continuous
and smooth and have the
concentrations of highly oriented platey
minerals.

Crenulation Foliations
 Microlithons contains the microfolds of
an earlier foliation.
 Crenulation foliations are formed by the
harmonic wrinkles or chevron folds in
preexisting foliation, the new foliation
cut across the old foliation.

Contineous Foliations
 Contineous foliations are defined either by
with a spacing less than 10micro-meter or by
non-domainal structure.
 Fabric elements are homogeneously
distributed.
 Consists of a non-layered homogeneous
distribution of platy mineral grains with a
preferred orientation.

Contineous Foliations
Fine continuous-
foliation
 e.g: Slate
Coarse continuous-
foliation
e.g: Schist

Lineations
1.Structrual
 A. discrete
 B. constructed
2.Mineral
 A.
polycrystalline
 B. mineral
grain

Structrual Lineations
 Structrual lineations are defined by the
preffered orientation of linear structure
contained in rock.
 It includes the discrete and constructed
lineations.

discrete
 Which are formed
by the
deformation of
discrete objects
such as ooids,
pebbles, fossils
etc.
constructed
 Which are formed
from planner
features constructed
or deformed during
deformations and
include the
intersection of two
foliations

Mineral Lineations
 Mineral lineations consist of preffered
orientation of either individual elongate
mineral grains or elongate
polycrystalline aggregates.
 i.e mineral lineations includes the
mineral grain and polycrystalline
lineations.

Mineral grain
 Mineral grain
lineations are
formed by the
parallel allignment
of individual acicular
(neddle like) mineral
grains.
polycrystalline
 Are formed by the
preffered
orientation of
elongate clusters
of grains of a
particular mineral.

Rods are polycrystalline mineral
lineations formed by the rod-shaped
concentrations of a particular
mineral commonly Qtz.

Foliations and lineations in rocks
referenced to pakistan
 As we know that foliations and lineations majorly
found in Metamorphic rocks.
 We shell have to travel up north, beyond Islamabad
to see the metamorphic rocks. However Kirana hills
near Sargodha also contains metamorphic rocks.
You may also find some in northern Balochistan
province e.g in Raskoh range. Around the
Nagarparkar high you may find metamorphic rocks
at its contect with the surrounding sedimentary
rocks.

Foliation and lineation

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