Observation

This question was not popular among the candidates and their performance in the question was poor. Majority of the candidates who attempted this question were not conversant with the procedure for formation of fold mountains and stack and were only making general statements about the formation and not specific steps in the process of formation of the features. Candidates’ scores for this question were generally low. They were expected to answer thus:

(a)Characteristics of stack

-it is a feature off the coast

-it is an emotional feature

-it is the remnants s of the headland standing seaward

-it varies in size

-the level of resistance determines the size

-further erosion of the stump may produce stump

-examples include the old man of Hoy and the needles

Formation

-formed by wave erosion

-presence of headland

-Wave erosion attacks headland at both sides

-two caves formed on the opposite sides of headland

-further erosion of caves produces an arch when caves join together

-roof of arc collapses.

-the sea ward portion of the headland remains as pillar called stack

(b) Characteristics of Fold mountain

-mountain produced by folding of rock strata

-produced by compression forces within the earth’s crust

-it is usually narrow and continuous

-made of large masses of folded sedimentary rocks

-has wrinkling appearance

-has steep slopes or gentle slopes

- the slopes are called limbs

-the fold has a crest which is the apex

-the fold has an axis which is the line which divides the fold into two equal parts

-mountain has up folds called anticlines

-mountain has down folds called synclines of the upfold

-there are several types of folds.

-some may be simples, asymmetricalover fold recumbent, over thrust/nappe

-folds may be several, minor and complex such as antclinorium and synclinorium

-varies in height

-are major mountain ranges of the world

-examples include The Atlas in morocco, Himalaya in Asia Everest in Asia etc

Formation

-formed by compression forces within the earth's crust

-presence of large depression called geosynclines

-materials eroded from blocks of sail are deposited in the geosynclines

-sedimentary rocks may be formed in the large depression geosynclines

-compression forces may cause the blocks surrounding the geosynclines to move towards each other

-the sedimentary rocks in the geosynclines folds up into up folds and down folds to produce the feature called fold mountain.