Sediments and sedimentary rocks - review questions for chapter 4

(also look at questions on p. 141 in the textbook)

What is the difference between the processes responsible for formation of clastic (or detrital) and chemical sediments? What minerals are clastic sediments generally made of and what minerals are commonly present in chemical sediments? What is biogenic sediment and what are some of the ways that it can form?

Transport and deposition of sediment commonly lead to formation of layering, stratification, or sedimentary structures. What does each of the following tell us about the dominant processes and environment of deposition: sorting, cross bedding, graded bedding, unsorted sediment layers, ripple marks, mud cracks, trace fossils.

What are the major particle-size classes used to describe clastic sediments, and what are the size ranges associated with each class? What do the particle size range and sorting of a sediment deposit tell us about how it formed? How is size related to settling velocity of a particle in water, and what does it tell us about the turbulence or flow velocity in the depositional environment? What does particle shape, and particularly the degree of angularity or roundness, tell us about a sediment sample?

What are the names of the major types of sedimentary rocks that are formed from clastic sediments? from chemical sediments?

Describe each of the major steps involved in the formation of a clastic sedimentary rock (weathering, erosion, transportation, deposition, burial, lithification and diagenesis). Which steps are different when a chemical sedimentary rock is being formed?

What are fossil fuels made of and how do they form?

Why are fossils potentially so important in reconstructing information about the environment of deposition?

Explain the concept of sedimentary facies and comment on how they may be used to provide evidence about depositional environments. (Note: examples of sedimentary facies from different environments are described on pp. 131-138.)