MBOSE Class 11 Question Paper 2019 for Geology

Total No. of Printed Pages––9
HS/XI/Sc/Gl/19

2019

GEOLOGY

( THEORY )

Full Marks : 70

Time : 3 hours

The figures in the margin indicate full marks for the questions

General Instructions:

(i) Write all the answers in the Answer Script.

(ii) Attempt Part–A Objective Questions serially.

(iii) Attempt all parts of a question together at one place.

( PART : A–OBJECTIVE )

( Marks : 35 )

1. Choose and write the correct answer : 1x6=6
(a). Water combining with a mineral component to
give rise to a new mineral is
(i) solution
(ii) hydration

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(2) (9)

(iii) hydrolysis GROUP – E

(iv) reduction ( Metamorphic Petrology )

(b) Topset, foreset and bottomset beds are associated 15. Briefly explain the common types of metamorphic
with structures. Draw suitable sketches. 7
(i) medial bar
(ii) point bar 16. Answer any two of the following: 3½ x 2 = 7

(iii) alluvial fan (a) Explain how contact metamorphism takes place.

(iv) delta (b) Write briefly on how metamorphic textures are
described.

(c) Explain how the grade of metamorphism of
(c) Change in colour of a mineral under crossed- argillaceous material can be ascertained.
Nicols as the microscope stage is rotated is called
(i) extinction
(ii) pleochroism 

(iii) interference color
(iv) twinning

(d) A change in shape, size, location or orientation
of a rock body is called
(i) deformation
(ii) folding
(iii) faulting
(iv) jointing

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(5) (6)

(c) A very greatly enlarged depression at the top of a 6. Answer in one or two lines on: 1x6=6
volcanic cone. (a) Seismograph

(d) A group of minerals indicating the degree of (b) Polarization of light
metamorphism. (c) Crystal

(d) Strike and dip of rocks
(e) A group of crystal faces intersecting the vertical
crystallographic axis. (e) Felsic and mafic igneous rocks

(f) Gneissose fabric

5. Match Column A with Column B and write the
corresponding numbers : 1x6=6 ( PART : B–DESCRIPTIVE )
Column A Column B ( Marks : 35 )
(a) Shadow zone (i) continuous reaction Answer five questions selecting one from each Group

(ii) contact metamorphism
(b) Solid solution
GROUP – A
(iii) isotropism
( General Geology )
(c) Aureole (iv) hybrid rocks
7. List the erosional work of a river. Explain the
(v) outer core formation of any two depositional landforms by rivers.
(d) Folds
1+6=7
(vi) ductile
(e) Glass 8. Answer any two of the following : 3½ x 2 = 7
(vii) discontinuous reaction
(a) Draw a neat labelled sketch of the interior of the
(viii) anisotropism earth.
(f) Assimilation
(ix) inner core (b) Write a note on recent thoughts about the origin
of the earth and the solar system.

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(4) (7)

(e) In metamorphism, the formation of new minerals (c) Write the Geological Time Scale in tabular form.
take place in the solid state, without undergoing
melting.
GROUP – B
(f) The North-East of India is categorized as zone I
in the earthquake zone Map of India. ( Crystallography and Mineralogy )

9. List the symmetry elements of the Normal Class of
3. Fill in the blanks : 1x6=6 the Hexagonal System. Draw a clinographic sketch of
the Hexagonal System. List the forms developed in
(a) The makes up the crust and uppermost the Normal Class of the Hexagonal System. Name a
mineral crystallizing in the Hexagonal System.
mantle.
1½ + 1 + 4 + ½ = 7
(b) Ordinary light breaking up into two polarized
10. Answer any two of the following: 3½ x 2 = 7
light is called .

(c) Folds with parallel limbs are called folds. (a) Explain the construction and working of the Nicol
prism.

(d) The point at which two minerals crystallize (b) Distinguish isotropic minerals from anisotropic
simultaneously from a melt is called the . minerals.

(c) Distinguish between the Cubic, Tetragonal and
(e) Granulites or eclogites is indicative of Hexagonal Systems.
grade of metamorphism.

(f) gives the inclination of a line in a rock. GROUP – C

( Structural Geology and Geotectonics )
4. Express in one word : 1x5=5
11. Define hinge line, fold axis and axial surface of folds.
(a) Very large, almost bottomless, igneous intrusion. State two points of difference between a fold and a
fault. What are recumbent folds, anticlines, and tight
(b) Actual relative displacement along a fault. folds? 3+1+3=7

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(8) (3)

12. Answer any two of the following: 3½ x 2 = 7 (e) Early formed heavy crystals settling to the bottom
of the magma chamber is called
(a) Plunge and rake / pitch, dip and strike. (i) fractional crystallization

(b) Dip-slip faults (ii) gravity settling

(iii) liquid immiscibility
(c) Plate boundaries
(iv) filter pressing

GROUP – D (f) A metamorphic fabric with a dominance of large
equidimensional minerals are called
( Igneous Petrology ) (i) granoblastic texture

(ii) porphyroblastic texture

13. Outline the different processes of magmatic (iii) blasto porphyritic texture
differentiation. 7
(iv) blasto ophitic texture

14. Answer any two of the following: 3½ x 2 = 7 2. State ‘ True’ or ‘False’ : 1x6=6

(a) Explain the crystallization of a simple (a) Natural earth processes were different at different
unicomponent melt. points in earth’s history.

(b) All crystals are divided in six systems.
(b) Outline the types of inequigranular texture seen
in plutonic igneous rocks. (c) Along dip-slip faults the hanging wall always
moves down relative to the foot wall.
(c) Explain any four intrusive igneous structures with (d) In ophitic texture, bigger crystals of plagioclase
sketches. enclose smaller grains of augite.

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