I) Historical Background

A) W. Smith-Similarities in Sequence

"Law" of Faunal Succession (actually observing fundamental evidence for evolution

B) Conflicting 19th Century Trends

1. Naming of lithologic sequences from type sections (result: Geological PERIODS)

2. Development of a concept of fossil succession devoid of lithologic context

3. Abstraction of time

a) Formalized by d'Orbigny- The STAGE and fossil assemblages
b) Oppel- The ZONE concept .

II) Types of Zones

A) Interval Zones- bounded by lowest and highest (i.e. first and last) occurrences of a single taxon (normal1y a species or subspp.) or group of taxa

1) Taxon Range Zone (single species)

2) Concurrent Range Zone (overlap or Oppel Zones)-overlap between first occurrence of a later taxon and last occurrence of an earlier one.

3) Lineage Zone- Successive related taxa forming a zonal sequence

4) Assemblage Zone- 3 or more taxa together

5) Acme Zone (Teilzone) Zone of maximal abundance

III) Utility of Fossils For Correlation

A) Abundance: Rare vs. common fossils

-large vs. small organisms
-long vs. short lived organisms

B) Range: Restricted (endemic) vs. Cosmopolitan

-what aspects of organisms'ecology would lead to these?

C) Biogeography: Regional vs. global biostratigraphic schemes

D) Habitat: Likelihood of fossilization

E) Biostratigraphically important groups

Paleozoic: Trilobites, Conodonts, Graptolites, Fusilinids
Mesozoic: Ammonites, Foraminiferans, Pollen, Ostracodes, other marine microfossils
Cenozoic: Pollen, Foraminifera, Diatoms, Radiolarians, Small Mammals, other marine microfossils

IV) Graphic (Shavian) Correlation

A) Plot first and last occurrences in 2 sections against arbitrary datum points

B) Repeat for numerous species and draw correlation line

C) Meaning of "x" and "y" intercepts and slope

D) Meaning of "dog-legs" in curve

E) Creation of the Reference Section

 

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