Biostratigraphy

Reading: Chapter 2

We only need p. 23-40.

Background

Terms:

Key Concepts and Questions:

1. What is the difference between the units defined in each of these kinds of stratigraphy? What are the uniots and how are they defined? Which units represent true time correlation?

Type of stratigraphy	What are the units?	How are they defined?	Are they true time units? Why or why not?
Lithostratigraphy
Biostratigraphy
Chronostratigraphy
Sequence stratigraphy
Cyclostratigraphy
Magnetostratigraphy

 

1. How are biostratigraphic units defined?

For each kind of zone, define it, and illustrate what the ranges of the index fossils involved look like (see fig. 2.2).

Type of Zone	Definition	Ranges of index fossils
total (taxon) range zone
concurrent range zone
interval zone (we'll do this one in class)
consecutive-range (lineage) zone
assemblage zone
acme (abundance) zone

2. What makes a good index fossil?

In class we will indentify the characteristics of a good index fossil. In your reading, note any characteristics you run across:

 

 

 

 

 

 

3. What factors affect the effectiveness of a biostratigraphic zonation?

How do each of these factors affect the utility/accuracy of a biostratigraphic scheme (we will do this in class)?

Evolution:

 

Facies dependence:

 

Emigration:

 

Preservation:

 

Erosion/Hiatus:

 

Extinctions:

 

Reworking:

 

 

Assessment

1. Biostratigraphic units

You should be able to:

• define and illustrate all the types of biostratigraphic zones
• given data on fossil ranges, define a zonations scheme using appropriate types of zones

2. Index fossils

You should be able to:

• describe the characteristics of a good index fossil
• analyze how the characteristic of specific organisms will impact their utility as index fossils

3. Factors affecting zonation

You should be able to:

• describe how each of the factors above could impact a zonation scheme
• analyze a specific zonation scheme for evidence of these factors