Full Text Transcript
Text below was recognized via OCR from scanned pages and may contain minor errors. Mathematical formulas and symbols may be approximate - please refer to the PDF for the exact equations.
Examination-20¢5 BGSP-B-GLG
GEOLOGY
Paper - II
Time Allowed : Three Hours Maximum Marks : 200
Question Paper Specific Instructions
Please read each of the following instructions carefully before attempting
questions :
There are ELEVEN questions divided under SIX sections.
Candidate has to attempt SIX questions in all.
The ONLY question in Section A is compulsory.
Out of the remaining TEN questions, the candidate has to attempt FIVE, choosing ONE
from each of the other Sections B, C, D, E and F.
The number of marks carried by a question/part is indicated against it.
Unless otherwise mentioned, symbols, abbreviations and notations have their usual
standard meanings.
Neat sketches are to be drawn to illustrate answers, wherever required. They shall be
drawn in the space provided for answering the question itself:
Wherever required, graphs/tables are to be drawn on the Question-cum-Answer (QCA)
Booklet itself.
Attempts of questions shall be counted in sequential order. Unless struck off, attempt of a
question shall be counted even if attempted partly.
Any page or portion of the page left blank in the Question-cum-Answer (QCA) Booklet must
be clearly struck off:
Answers must be written in ENGLISH only.
BGSP-B-GLG 1
ணை மாய
(Compulsory Section)
Ql. Describe the following in brief with diagrams and suitable examples,
wherever necessary :
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(1)
0)
BGSP-B-GLG
Draw stereogram for crystal class 2 (Sphenoidal class).
Name the members of plagioclase feldspar series and their composition
ranges.
Rubidium-Strontium geochronology.
Compatible and incompatible trace elements.
Crystal settling in magma chamber.
Distinguish between S-type and I-type granites.
Pressure solution.
Two-feldspar thermometer.
Give mineralogical and phase transformation changes at upper mantle
transition zone — 410 km discontinuity.
Draw a neat diagram showing forces acting at mid-oceanic ridges.
5x10=50
5
SECTION B
Attempt any one question.
Q2. (a)
(b)
Q3. (৪)
(b)
(૦)
Explain the coordination principle and discuss various possible
coordination numbers describing their geometry.
Discuss the structure and composition for mica group of minerals.
Explain the procedure for determining optic sign for uniaxial minerals.
Discuss mineral group with the general formula 20204. Explain series
of members due to substitution of associated cations.
Explain the terms ‘Primitive’ and ‘Non-primitive’ space lattice. Depict
the relationship of Bravais lattice with crystal system, using appropriate
figures.
"SECTION 0
Attempt any one question.
૦4. (a)
(b)
Q5. (৪)
(b)
(c)
` BGSP-B-GLG
Describe Goldschmidt’s rules for trace elements distribution. Discuss
interpretation of Eu and Ba anomalies.
Discuss applications of oxygen isotopes in paleoclimatic studies.
Describe the different varieties of meteorites and their possible sources.
Write the rules pertaining to the principles that govern the entry of
trace elements into minerals.
Write down the equation for Rayleigh’s fractionation law. A basaltic
magma (originally containing 940 ppm Ni) suffers fractional
crystallization of clinopyroxene crystal only. Find out the Ni
concentration in the derived magma if the parent magma suffers 20%
fractional crystallization. [Given : a = 4]
15
15
10
10
10
15
15
10
10
10
SECTION D
Attempt any one question.
Q6. (a)
(b)
87. 03) :
(७)
(८)
BGSP-B-GLG
Draw a neat labelled diagram of the Diopside-Anorthite system
(1 atm. dry) and describe the course of crystallization from two initial
melts [P, : 08604120 and 7൭ : 18049701. Deduce the degree(s) of freedom
at the eutectic point of this system. Give the system’s petrogenetic
significance.
(0) Explain batch melting and dynamic melting of the mantle.
(ii) Describe the assimilation phenomenon when a basaltic magma
assimilates a shale country rock.
Describe perthitic and myrmekitic textures. Explain their origin with
the help of relevant phase diagrams.
Give the ideal sequence for an ophiolite suite. Give the petrogenetic
account of the ophiolite suite of rocks.
Discuss the types of igneous rock textures. Comment on the significance
of poikilitic, porphyritic and flow textures. .
15
15
10
10
10
SECTION E
Attempt any one question.
8৪. (8)
(b)
൭9. (a)
(b)
(८)
BGSP-B-GLG
What are paired metamorphic belts and metamorphic facies series ?
Discuss the P-T conditions, tectonic setting, processes and mineral
assemblages involved in such metamorphic belts.
On a simple P-T- ১০০৯ diagram, show the mineral phases and reactions
that develop during regional metamorphism of an impure limestone.
Discuss with the help of neat sketches how porphyroblast-inclusion
relations can help in interpreting the temporal relationship between
tectonics and metamorphism.
Why is a system containing corundum, quartz, sillimanite and
andalusite termed ‘degenerate’ ? Draw the phase boundaries to show the
degenerate reactions among these minerals.
Describe the characteristics of ultra-high pressure metamorphism and
its tectonic conditions.
15
15
10
10
10
SECTION F
Attempt any one question.
౧1౦. (a)
(b)
০11. (a)
(b)
(૦)
BGSP-B-GLG
Draw a neat labelled sketch, label it and describe the generalized
morphology of an island arc system.
Compare and contrast between Apparent Polar Wander and True Polar
Wander curves.
Discuss causes for the magnetic reversals in the Earth’s Magnetic Field.
Discuss the sequence of events for the generation of plumes in the
Earth’s 1)'' layer.
Discuss paleontological evidence for Continental Drift.
15
15
10
10
10
