Ch 4 - Sedimentary Rocks Flashcards

Questions and Answers

What process is defined as the weight from the layers of sediment forcing out fluids and decreasing the space between grains?

Sedimentation

Erosion

Cementation

Compaction (correct)

What is the process when minerals dissolved in water crystallize between sediment grains?

Cementation (correct)

Compaction

Sedimentation

Erosion

What are clasts?

Broken pieces of minerals or rock fragments.

What are two ways that existing rock material can be transported to a new location?

As dissolved material in water and as fragments carried by water, glacial ice or wind. Signup and view all the answers

What is the difference between compaction and cementation?

Compaction occurs when sediment is squeezed together by the weight of other sediment above it, and cementation occurs when sediment is cemented together by dissolved minerals. Signup and view all the answers

Which type of sedimentary rock would have greater resistance to breaking down: one that formed by compaction only, or one that formed by both cementation and compaction? Explain.

The rock that formed by cementation and compaction would have greater resistance because it would have the added strength of the cement holding its grains together. Signup and view all the answers

In which way are both igneous and sedimentary rocks classified?

How they form. Signup and view all the answers

Describe two ways in which sedimentary rocks can form.

When sediment or other fragments are deposited, compacted, and cemented together, and when minerals crystallize out of water. Signup and view all the answers

Why can't sediment size alone be used to identify a sedimentary rock environment?

Sometimes the same rock environment can produce rocks with a variety of sediment sizes. The shapes of sediment offer clues about the rock environment. Signup and view all the answers

What would be a characteristic of a nonclastic sedimentary rock?

Nonclastic sedimentary rocks would be more uniform or made of a material that does not consist of fragments of other materials. Signup and view all the answers

How do chemical rocks form?

When minerals crystallize directly from water. Signup and view all the answers

What can happen to a rock when water flows through cracks or holes in the rock?

The water can dissolve some of the rock's minerals and carry them away. Signup and view all the answers

How do chemical and biochemical sedimentary rocks form?

Chemical sedimentary rocks form when minerals crystallize out of solution in water, and biochemical sedimentary rocks form from the action of organisms in water. Signup and view all the answers

What is the most common biochemical sedimentary rock?

Limestone. Signup and view all the answers

What happens to the sand in the valley if more sand is deposited on top of it?

The layers of sand would be buried under more layers of newer sand. Over time, the weight of the new sediment would squeeze out fluids and decrease the space between grains through compaction, which may lead to cementation of the sand. Signup and view all the answers

Which is a clastic rock?

Sandstone Signup and view all the answers

Coal is an example of a type of sedimentary rock called a(n) ___________________.

biochemical rock Signup and view all the answers

What process squeezes fluids from between individual grains?

Compaction Signup and view all the answers

What is the term for broken pieces of rock?

Clasts Signup and view all the answers

What process is occurring when minerals such as calcite or quartz crystallize between grains of clastic rock?

Cementation Signup and view all the answers

What is the general term for a rock fragment present in a sedimentary rock?

Clast. Signup and view all the answers

Which characteristics are used to classify a sedimentary rock such as sandstone?

Grain size Signup and view all the answers

List the terms below in the correct order to describe the formation of clastic sedimentary rocks.

<ol> <li>Erosion, 2. Transportation, 3. Deposition, 4. Cementation.</li> </ol> Signup and view all the answers

Distinguish among clastic, chemical, and biochemical sedimentary rock.

Clastic - made up of broken pieces of minerals and rock fragments. Chemical - made from minerals that crystallize out of water. Biochemical - sedimentary rock that forms from the remains of organisms. Signup and view all the answers

Study Notes

Sedimentary Rocks Overview

Formed through processes such as weathering, erosion, transportation, deposition, compaction, cementation, and crystallization.
Classified into three main types: clastic, chemical, and biochemical.

Key Processes

Compaction: Weight of overlying sediment forces out fluids, decreasing space between grains.
Cementation: Minerals dissolved in water crystallize between sediment grains, binding them together.
Formation of Clastic Rocks: Involves erosion, transportation, deposition, and cementation of rock fragments.

Types of Sedimentary Rocks

Clastic: Composed of broken pieces of minerals and rock fragments.
Chemical: Formed when minerals crystallize directly from water.
Biochemical: Originates from processes involving organisms, often containing their remains (e.g., coal, limestone).

Rock Characteristics

Clasts: Broken pieces of minerals or rock fragments; indicative of the source rock's properties.
Nonclastic rocks: More uniform, made from materials that do not consist of fragments.
Chemical Rocks: Typically consist of one mineral due to crystallization from saturated water.

Identifying Rocks

Limestone can form as a chemical rock from calcite or as a biochemical rock from fossil remains.
To identify limestone: add hydrochloric acid; a fizz indicates the presence of calcite.

Formation Conditions

Depositional environments can influence sediment size and shape, which may vary in the same environment.
Coal, a biochemical rock, contains no minerals; made of non-crystalline carbon.

Properties of Specific Rocks

Conglomerate vs. Breccia: Both are clastic but differ in clast shape; conglomerate has rounded clasts, while breccia has angular ones.
Common Biochemical Rock: Limestone is the most prevalent in this category.

Miscellaneous Facts

Water can dissolve minerals in rocks, contributing to seawater salinity as dissolved minerals are carried to the ocean.
Distinguishing textures and grain sizes of sedimentary rocks can reveal transportation distance and environmental history.

Processes Illustrated in Diagrams

Cementation and crystallization are critical stages in the formation of sedimentary rocks, often visible in visual learning materials.

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Description

Test your knowledge of sedimentary rocks with these flashcards covering key terms such as compaction, cementation, and clastic rocks. Each term is defined to help reinforce your understanding of the concepts covered in Chapter 4.