GENERAL GEOLOGY

GEOLOGY

ECONOMIC GEOLOGY

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
As magma cools, dense, metallic minerals sink to the bottom of the body of magma. Layers of these minerals accumulate and form ore deposits within the hardened magma.
A
Cooling Magma
B
Contact Metamorphism
C
Placer Deposits
D
Dissolving
Explanation: 

Detailed explanation-1: -This process is called fractional crystallization. The formation of olivine removes iron-and magnesium-rich components, leaving the overall composition of the magma near the top of the magma chamber more felsic. The crystals that settle might either form an olivine-rich layer near the bottom of the magma chamber.

Detailed explanation-2: -igneous rocks are also called volcanic rocks. They cool from magma slowly in the crust. They have large crystals.

Detailed explanation-3: -Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth’s surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles to settle in place.

Detailed explanation-4: -The minerals present will be olivine, pyroxene, and calcium-rich plagioclase. If the magma cools slowly underground, the product will be gabbro; if it cools quickly at the surface, the product will be basalt (Figure 3.13).

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