GEOL/VI/10 Student's Copy
2 0 1 8
6th Semester
GEOLOGY
TENTH PAPER
Geochemistry and Exploration Geology
Full Marks 55
Time 2½ hours
PART A—OBJECTIVE
Marks 20
The figures in the margin indicate full marks for the questions
SECTION—A
Marks 5
Tick the correct answer in the brackets provided 1×5=5
1. The concentration of an element in a rock compared with its average
concentration in the earth's crust is known as
background value
threshold value
clarke value
assay value
/521 1 Contd.
2. Elements that do not fit easily into rock-forming minerals are called
compatible elements
incompatible elements
high-field strength elements
large-ion lithophile elements
3. 1° latitude approximately equals
101 km
111 km
121 km
131 km
4. A positive gravity anomaly of underfoot rocks/minerals indicates
very low density
low density
moderate density
high density
5. A natural gamma ray log exhibits a high response from
shales
limestones
dolomites
coal
GEOL/VI/10/521 2 Contd.
SECTION—B
Marks 15
Write notes on the following 3×5=15
1. Trace element
2. Anomaly map
3. Threshold value
4. Oddo-Harkins rule
5. Theory of radioactivity
PART B—DESCRIPTIVE
Marks 35
The figures in the margin indicate full marks for the questions
Answer five questions, taking one from each Unit
UNIT—I
1. Write a detailed note on Goldschmidth's geochemical classification of
elements. 7
2. Write a note on geochemical evolution of the earth. 7
UNIT—II
3. Write a detailed note on primary and secondary dispersions of elements. 7
4. Write notes on the following 3½+3½=7
Pathfinder elements
Clarke value
GEOL/VI/10/521 3 Contd.
UNIT—III
5. Write in detail about geological field mapping. 7
6. Write notes on any two of the following 3½×2=7
Map scale
Principles of exploration
Survey of India toposheet
UNIT—IV
7. Discuss in detail the method of geochemical prospecting with suitable
examples. 7
8. Write notes on any two of the following 3½×2=7
Geozoological indicator application in mineral exploration
Assay map
Generation of geochemical profile
UNIT—V
9. Discuss in detail the resistivity method of geophysical exploration. Add a
note on its application in exploration geology.
10. Discuss in detail about the seismic refraction method of geophysical
exploration with a neat diagram.