2. WHAT IS A MOUNTAIN?
•A portion of land surface rising
considerably above the surrounding
country either as a single eminence
or in a range of chain is known as a
mountain.
3. TYPES OF MOUNTAINS
•Mountains are classified according to their
mode of formation.
•1. Fold mountains
2. Block mountains
3. Volcanic mountains
4. FORMATION OF FOLD
MOUNTAINS
•Fold mountains are created by crustal
bending due to internal forces of
compression from one or both sides.
•The folding of rocks produces anticline and
syncline. The uphold portion of the fold is
called anticline and the down portion of
fold is called syncline.
5.
6. CHARACTERISTICS OF
FOLD MOUNTAIN
• They are characterized by ruggedness of
relief.
• They are mostly constituted by sedimentary
rocks.
• They are mostly located on the margins of
the continents
8. TYPES OF FOLD MOUNTAIN
• Young fold mountains
• They are newly formed
and have more rugged
features like pointed
peaks, steeper and
deeper slopes.
• e.g. Himalayas
• Old fold mountains
• These mountains are
subjected to forces of
erosion for a long
period and hence, they
are much lower with
rounded peaks and
gentle slope.
• e.g Appalachians in
North America and
Aravallis in India.
9. FORMATION OF BLOCK
MOUNTAINS
• When the earth’s crust bend, folding occurs, but
when it cracks, faulting takes place.
• When two roughly parallel faults occur on the rock
strata, the block on the either sides may be raised
forming steep sided block mountain and the block
between the raised blocks gets subsided and forms
Rift valley.
12. MEANING OF FAULTING
• When rocks are subjected to horizontal
compressional forces they do not get folded but
break up along the lines of weakness.
• Due to this, the rocks get fractured. Such
fracture of rock is called faulting.
• The line of a fracture in the rocks is called a
fault.
13.
14. HOMEWORK
•1. In a notebook, draw the diagram of fold
mountain and block mountain neatly and
label its parts.
•2. Complete the google form.
