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Difficulty: EasyRock Types, Formation, and Economic Importance

Rocks are classified into three major groups based on their mode of formation. Which of the following features is a distinct characteristic of sedimentary rocks?

  1. Stratification into layers and frequent inclusion of fossilsAnswer
  2. B
    Interlocking crystalline structure resulting from deep thermal metamorphism
  3. C
    Down-slope mass movement of weathered debris driven purely by gravity
  4. D
    Foliated mineral banding formed by rapid cooling of molten volcanic lava

Answer

Stratification into layers and frequent inclusion of fossils is the key defining feature of sedimentary rocks.
Sedimentary rocks are created by the deposition of organic and inorganic particles in successive strata (bedding planes). Because the process takes place at normal ambient temperatures on the surface, dead organisms buried in these layers can be preserved as fossils.

Step-by-Step Solution

1
Identify the rock formation process described.
Sedimentary rocks accumulate in layers (strata) through weathering, erosion, deposition, and lithification.
Understanding how sediments settle in water or land bodies explains their structural appearance.
2
Analyze unique characteristics resulting from this process.
Because formation occurs at low temperatures on the Earth's surface, organic material (plants and animals) can be buried and preserved as fossils between bedding planes.
Igneous rocks destroy fossils due to high molten temperatures, and metamorphic rocks deform or destroy fossils under extreme heat and pressure.

Key Concept

Characteristics of Sedimentary Rocks
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Topics

Rock Types, Formation, and Economic Importance

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