25 Questions
What is a biostratigraphic unit characterized by?
Its fossil content
What is the main purpose of defining a biostratigraphic unit?
To differentiate it from adjacent strata
What is a biostratigraphic unit composed of?
A body of rock strata
What is unique about the fossil content of a biostratigraphic unit?
It is different from the surrounding rocks
What is the primary characteristic that defines a biostratigraphic unit?
Its fossil content
What can be used to date and characterize a unit of strata?
Fossil content
What is biostratigraphy closely allied to?
Paleontology
What is the primary focus of biostratigraphy?
Fossil distribution
What can be used to reconstruct the geologic history of an area?
Fossil record
What is the relationship between biostratigraphy and paleontology?
They are closely allied
What type of correlation is preferred by biostratigraphers?
Correlation based on assemblage biozones
What is chronostratigraphic correlation based on?
Time equivalence
Why do biostratigraphers not prefer correlation based on local provinces?
It is not applicable globally
What is the main purpose of chronostratigraphic correlation?
To match stratigraphic units based on time equivalence
What is the difference between chronostratigraphic correlation and biostratigraphic correlation?
Chronostratigraphic correlation is based on time equivalence, while biostratigraphic correlation is based on fossil type
What are the two broad categories of methods for establishing time-stratigraphic correlation?
Biological and Physical/chemical
What type of zones are used in time-stratigraphic correlation by biological methods?
Concurrent range zone and other interval zones
What is the chapter where physical/chemical methods are discussed?
Chapter 15
What are taxon range and interval zones that constitute?
The strata that fall between the highest and/or the lowest occurrence of strata
What is the characteristic of different biozones in time-stratigraphic correlation?
They have varying degrees of usefulness
What is a characteristic of interval biozones defined on the last appearance of taxa?
They have less time significance
What happens to taxa in the fossil record?
They gradually disappear and new species appear
What is the significance of the last appearance of taxa in a biozone?
It has less time significance
What is true about the extinction of taxa?
It is a gradual process
What is the relationship between the extinction of taxa and the appearance of new species?
The extinction of taxa is a gradual process that occurs as new species appear
Study Notes
Biostratigraphy and Fossil Content
- Any unit of strata can be dated and characterized by its fossil content.
- Biostratigraphy is closely allied to paleontology.
Biostratigraphic Units
- A biostratigraphic unit is a body of rock strata characterized by its fossil content that differentiates it from adjacent strata.
- Interval biozones defined on the last (stratigraphically highest) appearance of taxa commonly have less time significance.
- Extinction of taxa is not sudden, as new species appear.
Correlation Methods
- Chronostratigraphic correlation is the matching up of stratigraphic units on the basis of time equivalence.
- Methods for establishing time-stratigraphic correlation fall into two broad categories: biological and physical/chemical.
Biological Correlation Methods
- Time-stratigraphic correlation by biological methods is based mainly on the use of concurrent range zones and other interval zones.
- Taxon range and interval zones are biozones that constitute the strata that fall between the highest and/or the lowest occurrence of strata.
Characteristics of Biozones
- The different biozones have varying degrees of usefulness in time-stratigraphic correlation.
- Biostratigraphers usually prefer correlation based on assemblage biozones or taxon-range or interval biozones.
Learn about the relationship between biostratigraphy and fossil content, and how it is closely tied to paleontology. Understand the significance of fossil content in dating strata units.
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