Origin of Soil and Grain Size

Question 1

It is formed by weathering rocks.

Answer 1

Soil

Question 2

Formed by the solidification of molten magma ejected from deep within the earth’s mantle.Magma ceases its mobility below the earth’s surface and cools to form intrusive igneous rocks that are called ________.

Answer 2

plutons

Question 3

Describes the sequence by which new materials are formed as magma cools.

Answer 3

Bowen’s reaction principle

Question 4

which the minerals formed are different in their chemical composition and

crystalline structure,

Answer 4

discontinuous ferromagnesian reaction series,

Question 5

which the minerals formed have different chemical compositions with similar crystalline structures.

Answer 5

continuous plagioclase feldspar reaction series

Question 6

Common types of igneous rocks

Answer 6

Granite, gabbro, and basalt

Question 7

__________ is the process of breaking down rocks by mechanical and chemical processes into smaller pieces.

Answer 7

Weathering

Question 8

__________________ may be caused by the expansion and contraction of rocks from the continuous gain and loss of heat, which results in ultimate disintegration.

Answer 8

Mechanical weathering

Question 9

In _____________, the original rock minerals are transformed into new minerals by a chemical reaction.

Answer 9

chemical weathering

Question 10

is highly resistant to weathering and only slightly soluble in water.

Answer 10

Quartz

Question 11

The soils formed by the weathered products at their place of origin are called __________.

Answer 11

residual soils

Question 12

Fine grained soil is found at the surface, and the grain size increases with depth.

Answer 12

Fact

Question 13

At greater depths, _________ fragments may also be found.

Answer 13

angular rock

Question 14

transported by running water and deposited along streams

Answer 14

Alluvial Soils

Question 15

formed by transportation and deposition of glaciers

Answer 15

Glacial Soils

Question 16

formed by deposition in quite lakes

Answer 16

Lacustrine soils

Question 17

formed by deposition in the seas

Answer 17

Marine soils

Question 18

transported and deposited by wind

Answer 18

formed by movement of soil from its original place by gravity,, such as during landslides

Question 19

The deposits of gravel, sand, silt, and clay formed by weathering may become compacted
by overburden pressure and cemented by agents like iron oxide, calcite, dolomite, and
quartz. Cementing agents are generally carried in solution by ground-water. They fill the
spaces between particles and form sedimentary rock. Rocks formed in this way are called
_____________________.

Answer 19

detrital sedimentary rocks

Question 20

In the case of conglomerates, if the particles are more angular, the rock is called ______.

Answer 20

breccia

Question 21

In _______, the particle sizes may vary between mm and 2 mm.

Answer 21

sandstone

Question 22

When the grains in sandstone are practically all quartz, the rock is referred to as _____________.

Answer 22

orthoquartzite

Question 23

In _____________, the size of the particles are generally less than mm. Mudstone has a blocky
aspect; whereas, in the case of shale, the rock is split into platy slabs.

Answer 23

mudstone and shale

Question 24

_________ is formed mostly of calcium carbonate deposited either by organisms or by an
inorganic process.

Answer 24

Limestone

Question 25

______ is a sed-
imentary rock made in part from biochemically derived calcite, which are skeletal fragments of microscopic plants and animals.

Answer 25

Chalk

Question 26

____________ is formed either by chemical deposition of mixed carbonates or by the reaction of magnesium in water with limestone.

Answer 26

Dolomite

Question 27

___________ result from the precipitation of soluble CaSO4 due to evaporation of
ocean water.

Answer 27

Gypsum and anhydrite

Question 28

___________ is the process of changing the composition and texture of rocks (without melting) by heat and pressure.

Answer 28

Metamorphism

Question 29

______ are mostly flake-shaped microscopic and submicroscopic particles of mica,
clay minerals, and other minerals.

Answer 29

Clays

Question 30

________________ are complex aluminum silicates that develop plasticity when mixed
with a limited amount of water.

Answer 30

Clay minerals

Question 31

_________________ is a process for determining the size range of particles present
in a soil mass. ________________ are two tests used in the
mechanical analysis of soil.

Answer 31

Mechanical analysis
Sieve analysis and hydrometer analysis

Question 32

________ is based on the principle of sedimentation of soil grains in water.

Answer 32

Hydrometer analysis

Question 33

____________ consists of shaking the soil sample through a set of sieves that have progressively
smaller openings.

Answer 33

Sieve analysis

Question 34

for particle sizes larger than 0.075
mm in diameter,

Answer 34

Sieve analysis

Question 35

analysis—for particle sizes smaller than 0.075 mm in
diameter.