Chapter 10 Questions 2

Question 1

Compare sandstone, siltstone, and shale.

Answer 1

• Sandstone: .0625 mm - 2mm in diameter, clasts rounded by erosion, different colors from different cementing compounds.
• Siltstone: .0625 mm in diameter, rough/gritty, breaks at an angle to OG sedimentary layers.
• Shale: .0625 mm in diamter, finer/soft, breaks in layers parralel to sed. rock.

(both siltstone and shale usually contain fossils)

Question 1

From a youung-earth view of earth’s history, what are the most important conclusions we can come to about the so-called rock cycle?

Answer 1

1. There hasn’t been enough time for most of this process to be completed
2. The earth was not created to recycle rocky materials
3. Sedimentary rocks turning into magma only happens along subduction zones, which are probably left over from the flood.

Question 2

What are the four steps by which most sedimentary rocks formed?

Answer 2

1. Erosion
2. Deposition
3. Compaction
4. Cementation

Question 3

How are clastic sedimentary rocks classified?

Answer 3

By the size of the grains or clasts in the rock.

Question 4

Describe regional, contact, and dynamic metamorphism.

Answer 4

1. Regional: Associated with the tectonic processes that create mountains.
2. Contact: Near dikes & sills, compressing rock - altering chem. comp., high temp. most important factor, stationary rock.
3. Dynamic: Rapidly changing conditions within rocks; Grinding against fault lines, making crystals deform & realign to the fault.