Geography Ch.2

Q.4 Answer the following questions in one or two words:

1. a. Mountains, Plains

b. Geologists

c. 35 kilometers

d. Two

e. Magnetite

5. Answer the following questions in brief.

a. Geology is the scientific study of the Earth's physical structure, its history, and the processes that act upon it.

b. Igneous rocks are formed from the solidification of molten magma or lava.

c. Petrology is the branch of geology that studies the origin, composition, distribution, and structure of rocks.

d. Continental crust is the outermost layer of Earth’s lithosphere that makes up the continents.

Oceanic crust, the outermost layer of Earth’s lithosphere that is found under the oceans .

e. Extrusive rocks form from lava cooling quickly on the Earth's surface, resulting in fine-grained or glassy textures.

e.g. Basalt

Intrusive rocks form from magma cooling slowly beneath the Earth's surface, resulting in coarse-grained textures with large crystals.

e.g. Granite

6. Answer the following questions in detail:

a. The Earth's interior is composed of three main layers:

1. Crust:The outermost solid layer, thin and brittle, divided into continental and oceanic types.

2. Mantle: Located beneath the crust, it is a thick, semi-solid layer involved in tectonic movements.

3. Core: The innermost layer, consisting of a liquid outer core and a solid inner core, primarily made of iron and nickel.

b. Rocks are naturally occurring solid aggregates of minerals. They form through three main processes:

1. Igneous Rocks: Form from cooling and solidifying molten rock (e.g., granite, basalt).

2. Sedimentary Rocks: Form from the compaction of sediments (e.g., sandstone, limestone).

3. Metamorphic Rocks: Form from the transformation of existing rocks due to heat and pressure (e.g., marble, slate).

c. The rock cycle is the continuous process through which rocks are transformed from one type to another. It involves three main types of rocks: igneous, sedimentary, and metamorphic. Rocks change forms through various processes such as cooling, erosion, sedimentation, compaction, and metamorphism. This cycle illustrates the dynamic and interconnected nature of Earth's geology.

d. Rocks and minerals are used for construction, manufacturing, energy production, technology, agriculture, jewelry, healthcare, and industrial processes.

e. Metamorphic rocks form from existing rocks exposed to high heat, pressure, or chemically active fluids, altering their mineral composition and structure without melting.


Slate: Formed from shale through low-grade metamorphism.

Marble: Formed from limestone through high heat and pressure.

Gneiss: Formed from granite through high-grade metamorphism, characterized by banded layers of minerals.

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