Goa Board Class 12 Question Paper Mar 2019 Geology

2019 III 11 1000 Seat No.

Time : 2½ Hours GEOLOGY

Subject Code

H 7 0 6

Total No. of Questions : 5 (Printed Pages : 7) Maximum Marks : 55

INSTRUCTIONS : (i) All questions are compulsory.

(ii) Draw neat labelled diagram wherever necessary.

(iii) Answer each question on a fresh page.

(iv) Write the question numbers and sub-question numbers

clearly.

(v) Draw neat labelled diagrams wherever necessary.

(vi) Answers to the questions carrying 1 mark should be written

in 1 to 10 words.

(vii) Answers to the questions carrying 2 marks should be written

in about 50 words.

(viii) Answers to the questions carrying 3 marks should be written

in about 80 words.

(ix) Answers to the questions carrying 4 marks should be written

in about 120 words.

(x) Select the correct alternative for multiple choice

questions and rewrite the statement.

H-706 1 P.T.O.

1. (A) Complete the following statement by choosing the correct

alternative given below the statement and write the completed

statement : 1

The continuous outermost solid layer of the earth is ....................

• Asthenosphere

• Oceanic crust

• Mantle

• Continental crust

(B) What do you understand by the term ‘‘Volcanic Block’’ ? 1

(C) Which landform is created at an initial stage of divergence of two

continental plates ? State an example. 2

(D) How are cinder cones formed ? 2

Or

How are Dome mountains formed ?

(E) What is Gutenberg discontinuity ? State its significance. 2

(F) Explain in brief : 3

• Formation of Andes mountains

• Formation of Composite volcano.

H-706 2

2. (A) Complete the following statement by choosing the correct alternative

given below the statement and write the completed statement : 1

A very coarse grained clastic sedimentary rock of varied composition

is termed as ....................

• Argillaceous rock

• Arenaceous rock

• Rudaceous rock

• Calcareous rock

(B) State the parent rock of Gneiss. 1

(C) Give an account of grain size and its relationship with rate of cooling

in igneous rocks. Give an example of igneous rock of inequigranular

texture. 2

(D) Distinguish between shale and sandstone based on grain size and

mineral composition. 2

(E) Explain the various grades of metamorphism. 2

(F) Explain the following : 3

• Contact metamorphism

• Directive texture.

H-706 3 P.T.O.

Or

Explain the following :

• Degree of crystallinity

• Clastic texture.

3. (A) Complete the following statement by choosing the correct alternative

given below the statement and write the completed statement : 1

A joint that strikes parallel to the dip of a bed is known as ..............

• Bedding joint

• Oblique joint

• Strike joint

• Dip joint

(B) Draw a neat labelled diagram of a plunging fold. 1

(C) Define the term outcrop. Which structural feature is observed in the

rocks outcropped at Gilbert Hill, Andheri Mumbai ? 2

(D) With a neat labelled diagram explain the formation of an angular

unconformity. 2

(E) Explain the following : 2

• Tensional joints

• Master joints.

H-706 4

(F) With a neat labelled diagram explain the following : 3

• Normal fault

• Chevron fold.

Or

With a neat labelled diagram explain the following :

• Reverse fault

• Fan fold.

4. (A) Complete the following statement by choosing the correct alternative

given below the statement and write the completed statement : 1

The mineral that occurs as beach sand is ..................

• Hematite

• Galena

• Pyrolusite

• Monazite

(B) Which metal is mined from Khetri area of Rajasthan ? 1

(C) Define ore mineral. With an example state the chemical composition

of the ore mineral of chromium. 2

H-706 5 P.T.O.

(D) Explain the following : 3

• Magmatic segregation

• Cut off grade.

(E) Explain the following : 4

• Formation of placer deposits.

• Various kinds of vien type of hydrothermal deposits.

5. (A) Complete the following statement by choosing the correct

alternative given below the statement and write the completed

statement : 1

The largest expanse of time on the standard Geological Time Scale

is ..................

• Era

• Epoch

• Period

• Eon

(B) State the age of Deccan trap volcanism. 1

(C) State the classification of Dharwar and Cuddapah supergroups. 2

H-706 6

(D) Explain the following : 3

• Cretaceous period

• Principle of inclusion

• Lithostratigraphic units.

(E) Explain the various methods of stratigraphic correlation. 4

Or

Explain the various modes of preservation of fossils.

H-706 7 P.T.O.