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Zorluk: OrtaRock Types, Formation, and Economic Importance

A geologist examining a rock specimen observes that it has a coarse-grained texture with large, visible mineral crystals of quartz and feldspar, indicating slow cooling deep beneath the Earth's surface. Which of the following rocks best matches this description?

  1. GraniteCevap
  2. B
    Basalt
  3. C
    Sandstone
  4. D
    Slate

Cevap

Granite is an intrusive igneous rock characterized by a coarse-grained crystalline texture formed through the slow cooling of molten magma beneath the Earth's surface.
Granite forms when magma cools slowly beneath the Earth's crust. This extended cooling period allows mineral crystals such as quartz and feldspar ample time to grow, producing a coarse-grained interlocking texture characteristic of plutonic igneous rocks.

Adım Adım Çözüm

1
Analyze the structural texture and mineral composition described in the question stem.
The presence of large, visible crystals of quartz and feldspar indicates a coarse-grained, phaneritic texture.
Crystal size in igneous rocks is directly controlled by the cooling rate of molten material.
2
Determine the mode of origin based on the cooling rate.
Slow cooling occurs deep within the Earth's crust under high pressure (plutonic/intrusive origin).
Crustal insulation slows heat loss, allowing minerals sufficient time to grow well-defined crystals.
3
Match the cooling mode and mineral composition to the correct rock specimen.
Granite is the principal coarse-grained intrusive igneous rock composed mainly of quartz and orthoclase feldspar.
Extrusive rocks cool too rapidly to form coarse crystals, whereas sedimentary and metamorphic rocks develop through secondary surface or metamorphic processes.

Anahtar Kavram

Intrusive vs Extrusive Igneous Rock Textures and Origin
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Konular

Rock Types, Formation, and Economic Importance

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