1. Index Fossils, Evolution, Biostratigraphy and the Geologic Time Scale

2. Bio-Events First appearances of new species
First appearances of new higher taxa
Extinctions of species
Mass extinctions of multiple taxa
Bio-events are unique points in geologic time

3. Index Fossils
Some fossils are more useful than others for relative age determinations
Fossils that are most useful are called INDEX FOSSILS
What factors would maximize a fossil’s usefulness?

4. Index Fossils Limited Stratigraphic Range
Widespread Geographic Distribution
Commonly Pelagic
Or, tolerant of a wide variety of environments (found in many facies)

5. Geologic Time Scale Standard subdivisions of Earth’s history
A “common language” by international agreement
Bio-Events are used to subdivide Geologic Time
Stratotypes or “type examples” are designated so comparisons can be standardized

6. Geologic Time Scale A hierarchy of time units Eon
Period
Epoch
Age
Boundaries are defined by bio-events

7. Eons Phanerozoic – “obvious life” – 530 Ma to present
Proterozoic – “prototypical life” – 2.5 Ga to 530 Ma
Archean – “ancient” – circa 4.6 Ga to 2.5 Ga
Archean and Proterozoic comprise nearly 90% of Earth’s history!

8. Phanerozoic Eon Cenozoic Era – “modern life” – 65 Ma to present
Mesozoic Era – “middle life” – 248 Ma to 65 Ma
Paleozoic Era – “ancient life” – 543 Ma to 248 Ma

9. Learn the following (in order from oldest to youngest):
3 Eons
3 Eras of the Phanerozoic
All of the Periods of the Phanerozoic and the Eras to which they belong
“Picks” – numerical ages of the boundaries between Eons and between Eras

10. Index Fossils and International Stratotypes
Biostratigraphy and Global Politics

11. Systems, Series, Stages Devonian System Silurian System
Upper Devonian Series
Famennian
Frasnian
Middle Devonian Series
Givetian
Eifelian
Lower Devonian
Emsian
Pragian
Lochkovian
Silurian System
Upper Silurian Series
Přídolí Stage

12. Index Fossils and the S-D Boundary
Graptolites *
Conodonts *
Chitinozoans *
Trilobites
Brachiopods
Cephalopods

13. Definition of the S-D Boundary
Stratotype: Klonk, near Suchomasty, Czech Republic

14. S-D GSSP GSSP = Global Stratotype, Sequence and Point
First appearance of Monograptus uniformis uniformis
Bed 20
Klonk, Czechia