MBOSE Class 11 Question Paper 2020 for Geology

(8) Total No. of Printed Pages ––8
HS/XI/Sc/Gl/20
GROUP – D
( Igneous Petrology ) 2020

13. Write brief notes on the common igneous textures
related specifically to mutual relation between grains. GEOLOGY
Draw neat sketches. 7
( THEORY )
Or
Full Marks : 70
14. Answer any two of the following : 3½ x 2 = 7
(a) Write on Extrusive Igneous rocks and their Time : 3 hours
distinctive textures and/or structures.
(b) Distinguish discontinuous and continuous The figures in the margin indicate full marks for the questions
reaction series.
General Instructions:
(c) Write a note on the concept of magmatic
differentiation. List the processes of magmatic (i) Write all the answers in the Answer Script.
differentiation. (ii) Attempt Part–A Objective Questions serially.

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

( Metamorphic Petrology )
( PART : A–OBJECTIVE )
15. Explain in words any two types of metamorphism.
3½ + 3½ = 7 ( Marks : 35 )
Or

16. Answer any two of the following : 3½ x 2 = 7 1. Choose and write the correct answer : 1  6=6
(a) Metamorphic grades
(a) The geological period immediately following
(b) Write notes on any two metamorphic textures. Devonian is
(c) Distinguish schistosity from gneissosity. (i) Cambrian

 (ii) Carboniferous

HS/XI/Sc/Gl/20 HS/XI/Sc/Gl/20

(6) (3)

(c) Anticline (e) A medium grade metamorphism is indicated
by the presence of the mineral
(d) Felsic minerals
(i) chlorite
(e) Gneissic structure
(ii) garnet
(f) Dyke
(iii) kyanite

(iv) sillimanite
( PART : B–DESCRIPTIVE )

( Marks : 35 ) (f) The average density of the earth is

Answer five questions selecting one from each Group (i) 2.60

(ii) 3.20
GROUP – A
(iii) 5.52
( General Geology )
(iv) 8.20

7. Define weathering and denudation. How does running
water bring about weathering? 2+ 5=7 2. State ‘True’ or ‘False’ : 1  6=6

Or (a) The mildest of volcanic eruptions is the Hawaiian
type.
8. Answer any two of the following : 3½ x 2 = 7
(b) Isotropic minerals exhibit double refraction but
(a) River meander and associated features. anisotropic minerals do not.

(b) Draw a neat labelled sketch of the earth’s interior. (c) The color of a mineral between positions of
extinction is called interference color.
(c) Tectonic causes of earthquakes. (d) Sills are discordant bodies in country rocks.

HS/XI/Sc/Gl/20 HS/XI/Sc/Gl/20

(4) (5)

(e) Quartz crystallizes early from a basaltic (c) A very large division of geological time.
magma.
(d) Mixing of magma and country rocks.
(f) Two or more parallel joints make up a joint
system. (e) Minerals appearing dark under crossed-Nicols in
a microscope.

3. Fill in the blanks : 1  6=6
5. Match Column A with Column B and write the
(a) The transverse profile of a river valley is ______.
corresponding numbers : 1  6=6
(b) The term ‘resinous’ is associated with the
property of _______ of a mineral.
Column A Column B
(c) When smaller crystals are embedded within
(a) Wall (i) vesicular
larger crystals, the texture is called _______.
(b) Mafic (ii) banded
(d) The temperature at which two minerals
crystallize simultaneously is called the (c) Schistose (iii) meander
_______ point. (d) Volcanics (iv) fold

(e) At great depths, the deformation of rocks is (e) Plunge (v) nebula
likely to be _______ type of deformation.
(f) Earth (vi) pyroxene, biotite
(f) The metamorphic structure produced under (vii) fault
very high temperature and pressure
conditions is the _______ structure. (viii) quartz, feldspar
(ix) foliated platy.

4. Express in one word : 1  5=5
(a) Outer rigid part of the earth. 6. Answer in one or two lines : 1  6=6

(b) Fine grained minerals around larger crystals (a) Point bar
in igneous rocks. (b) Dip and plunge

HS/XI/Sc/Gl/20 HS/XI/Sc/Gl/20

(2) (7)

(iii) Cretaceous GROUP – B

(iv) Cenozoic ( Crystallography and Mineralogy )

9. List the symmetry elements of the Normal class of the
Isometric System. Draw a clinographic sketch of the
(b) The vibration of light along one definite plane is Isometric System. List the forms developed. Name a
called mineral crystallizing in the Isometric System.
(i) polarization 1½ + 1 + 4 + ½ = 7
Or
(ii) pleochroism
10. Write a note on any two of the following : 3½ x 2 = 7
(iii) double refraction (a) Symmetry elements of crystals.
(iv) anisotropism (b) Anisotropism.
(c) Double refraction.
(c) The actual movement along faults is called
(i) fault plane GROUP – C
(ii) heave ( Structural Geology and Geotectonics )
(iii) throw
11. Define slip along faults. Write a note on the
(iv) slip classification of faults based on slip, with sketches.
1+ 6=7
Or
(d) Fragments of country rocks within magmas are
called 12. Answer any two of the following : 3½ x 2 = 7

(i) pillow structure (a) Distinguish between symmetrical and
asymmetrical folds and plunging and non-
(ii) flow structure plunging folds.
(iii) xenolith (b) Write a note on joints.

(iv) protolith (c) What are plate motion and plate boundaries.

HS/XI/Sc/Gl/20 HS/XI/Sc/Gl/20