The document discusses key concepts related to the geometry and elements of rock folding. It defines folding as the bending of rock strata due to compressional forces, which results in a wavy formation of the earth's surface known as folds. Folds are described by their form and orientation. Key elements of folds discussed include limbs, which are the segments of rock beds between the crest and troughs of a fold, and hinge lines, which connect the points of maximum curvature in a folded sequence. The document also defines axial planes, fold axes, plunge, and features such as crests, troughs, and inflection points.

1. Geometry and
elements of
fold

2. The bending of rock strata of
plastic nature due to
compressional forces acting
horizontally towards a common
point or plane from opposite
directions is known as folding.
INTRODUCTION

3. It results in the crumbling of
strata , resulting in a wavy
formation on the surface of the
earth , which are known as
folds.
Folds are described by their
form & orientation.
CONTINUE...

5. The stretch of the rock beds lying
between any crest and any of the
adjacent troughs on either sides is
known as the limb of the fold.
The limb may be then redefined as the
fold segment between a hinge line and
the adjacent inflection line.
1.LIMBS

7. A point can be found where curvature is
maximum is called hinge point.
When rocks occur in a sequence & their
all hinge points are joined together ,
they make a line , called the hinge line.
2.HINGE

9. An axial plane is that imaginary plane
that passes through all the points of
maximum curvature in a folded
sequence.
It may be vertical , inclined or
horizontal in nature.
3.AXIAL PLANE

11. A line drawn parallel to the hinge line of
a fold.
A precise definition is the line
representing the intersection of the
axial plane of a fold with any bed of the
fold.
4.AXIS OF A FOLD

13. The angle of inclination of the fold axis
with the horizontal as measured in a
vertical plane is termed the plunge of
the fold.
In other words , plunge is the angle
which this line makes with a horizontal
plane.
5.PLUNGE OF A FOLD

15. Crest-Highest points in an uparched
fold.
Trough-Lowest point in a downarched
fold.
Inflection point-A point on a fold at
which the fold changes from syncline
to anticline or vice versa.
6.CREST,TROUGH & INFLECTION
POINT

17. Engineering & general geology-Parbin
Singh.
A textbook of geology-G.B.Mahabatra
https://en.wikipedia.org/wiki/File:Flank_
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https://en.wikipedia.org/wiki/File:Agiosp
avlos_DM_2004_IMG002_Felsenformati
on.JPG
REFERNCE

18. THANK YOU
A-TEAM