BALOCHISTAN PUBLIC SERVICE COMMISSION
Samungli Road, Quetta Cantt.
COMPETITIVE EXAMINATION FOR THE POST(S) OF BCS (EB) OFFICER B-17
GEOLOGY
Marks:150 Saturday, March 17, 2007 (02:30 PM) Time: 03 Hours
Note: Attempt any Five questions. Question No.1 is Compulsory.
All questions carry equal marks. Make sketches and diagrams where necessary.
Q 1. Fill in the blanks:
(i) According to the theory of Plate Tectonics, ______ boundaries are the zones where plates separate or move apart from each other.
(ii) A ______ is a naturally occurring inorganic solid with definite chemical composition and a crystalline structure.
(iii) ______ rocks form when rocks of any type re-crystallize due to high temperatures or pressures or when they change due to deformation.
(iv) ______ rocks are low in silica, high in iron and magnesium, contain calcium-rich plagioclase, pyroxene and olivine and are dark in colour.
(v) ______ is the physical removal of weathered rock or soil by moving water, wind, glaciers, or gravity.
(vi) ______ are composed of lithified clastic sediment and are named and classified primarily according to the size of the clastic grains.
(vii) ______ metamorphism occurs when country rock is heated by nearby igneous intrusion.
(viii) A ______ is a preserved impression made in rock or sediment by the exterior or interior of a shell or other body part.
(ix) A ______ consists of rock or sediment that fills a mold.
(x) Absolute time is measured mainly by radioactive age dating, which relies on the fact radioactive parent isotopes contained in rocks and minerals decay to form daughter isotopes at a fixed, known rate, expressed by the ______ of the isotope.
(xi) ______ are fossils of organisms that were geographically widespread, but which lived for only a relatively short time.
(xii) The ______ scale is a qualitative scale that measures earthquake intensity.
(xiii) The ______ is the relatively cool, brittle 100 km thick outer layer of the Earth.
(xiv) The concept that the lithosphere floats on the asthenosphere is called ______.
(xv) The ______ is a continuous sub-marine mountain chain that extends through all of the Earth’s major ocean basins.
(xvi) A ______ margin, where continental crust is firmly joined to oceanic crust, include a continental shelf, slope, and rise, formed by accumulation of sediments in the region where continental crust joins oceanic crust.
(xvii) A ______ is an elongate trough in the ocean floor formed where oceanic crust dives downward at the subduction zone.
(xviii) ______ is a type of flow that occurs when water-saturated soil moves over permafrost.
(xix) The ______ of a stream is a measure of the largest particles that the water can transport.
(xx) Of the water that falls on land, most percolates downward into soil and bedrock to become ______.
(xxi) An ______ is a body of porous and permeable rock that can yield economically significant quantities of water.
(xxi) A ______ is a massive, long-lasting accumulation of compacted snow and ice that forms on land and flows in a plastic manner.
(xxiii) ______ lakes are desert lakes that dry up periodically leaving abundant lake beds called playas.
(xxiv) A ______ is a mound or ridge of wind-deposited sand.
(xxv) Plagioclase, orthoclase, and microcline are different kinds of ______.
Q 2. What is a “Rock Cycle”? Define igneous, metamorphic and sedimentary rocks. Give two examples of each rock type.
Q 3. What do you know about the theory of plate tectonics? What are the evidences that support this theory?
Q 4. Describe the common physical properties that a geologist uses to identify a mineral.
Q 5. What is Crystallography? Briefly describe all the crystallographic systems.
Q 6. What is metamorphism? Describe all the types of metamorphism in detail. What are the possible locations in Balochistan to find metamorphic rocks?
Q 7. What do you understand by the term “stratigraphy”? What are the principles of stratigraphy? Make a stratigraphic column of the Mesozoic and Cenozoic rock units exposed in the Quetta region and describe the lithology and contact relationships of each unit.
Q 8. How are fossils preserved in rocks and why are they important in geology? Draw a generalized sketch of a gastropod and identify columella, whorl, aperture, suture, and conch.
Q 9. Write down the chemical composition of the following minerals:
| Graphite | Gypsum | Chalcedony | Hematite | Kyanite | Magnetite | Apatite |
| Barite | Albite | Calcite | Celestite | Halite | Chromite | Corundum |
| Diamond | Dolomite | Fluorite | Galena | Malachite | Anorthite | Olivine |
| Orthoclase | Pyrite | Pyroxene | Quartz | | | |
Good Luck
Answer Key Q 1
(i) Divergent, (ii) Mineral, (iii) Metamorphic, (iv) Mafic (or Basaltic), (v) Erosion, (vi) Detrital sedimentary rocks (or Clastic sedimentary rocks), (vii) Contact, (viii) Mold, (ix) Cast, (x) Half-life, (xi) Index fossils, (xii) Mercalli (or Modified Mercalli Intensity), (xiii) Lithosphere, (xiv) Isostasy, (xv) Mid-ocean ridge (or Mid-oceanic ridge), (xvi) Passive, (xvii) Trench (or Oceanic trench), (xviii) Solifluction, (xix) Competence, (xx) Groundwater, (xxi) Aquifer, (xxii) Glacier, (xxiii) Playa (or Ephemeral / Saline), (xxiv) Dune (or Sand dune), (xxv) Feldspar
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