Biostratigraphy The art and science of telling time from rocks.

1. Biostratigraphy The art and science of telling time from rocks. Traditional core of paleontology, and of geology. The geologic time scale is all based on fossils, relative time scale. Most paleontologists working in industry do biostratigraphy. GG 309 Craig Glenn Spring 2012

2. Fossils • Index Fossils and Fossil Assemblages Good for 3 Things: • Understanding Evolution • Biostratigraphy (Stratigraphic Correlation) • Environmental Interpretation Biostratigraphy: • Characterization and correlation of rock units based on fossil content • Based on the recognition that organisms have evolved • Closely linked to paleontology • UNDERSTANDING THE ENVIROMENTAL CONTROLS IS CRITICAL TO: • SUCCESSFUL BIOSTRATIGRAPHIC ANALYSIS • SUCCESSFUL INTERPRETATION OF DEPOSTIONAL SYSTEMS

3. THE MOST CRITICAL FACTORS AFFECTING CHRONOSTRATIGRAPHIC SIGNIFICANCE IN BIOSTRATIGRAPHY ARE: 1. EVOLUTION 2. MIGRATION 3. EXTINCTION 4. ENVIRONMENT 5. PRESERVATION

4. EVOLUTION RATES? A. Phyletic gradualism Gradual Morphology Schematic ‘family tree’ (body characteristics) B. Punctuated equilibrium Charles Darwin Rapid Morphology Schematic ‘family tree’ (body characteristics) In punctuated model, speciation occurs only1000s (100s?) yrs, after population becomes reproductively isolated from the parent population.

5. THE TAXONOMIC CLASSIFICATION OF LIFE - based on # shared characteristics (or differences) - Animal, Plant, Fungi, Protist, Archaebacteria single-celled plant-like Protophyta algae: Coccoliths & Diatoms single-celled animal-like Protozoa: Forams & Radiolaria Cover of Linnaeus’ 10th edition of Systema Naturae (1758) Carolus Linnaeus after BOGGS, 14.5

6. Tertiary Sediments of the Gulf Plain Biostratigraphic Units are Not Lithostratigraphic Units - Not the Same Thing The Biostratigraphic Unit will correspond to the Lithostratigraphic unit if the fossils are FACIES CONTROLLED.

7. Methodology • INDEX • FOSSILS ARE: • independent • of environment • short range • widespread INDEX FOSSILS: Important Marine Forms of the Phanerozoic white bars show total range; black bars show times when imp. Index fossil.

8. The Finer Points of Stratigraphy

9. You decide… Index Fossils:Which One’s Better? ThisClassic 1958 Edsel Beauty? OR The Classic Utilitarian Volkswagen Beetle? (the “people’s car”)

10. “Lookie there, its gots its darn engine in the back!” • INDEX • FOSSILS: • independent • of environment • short range • widespread Herbie goes abroad Volkswagen Beetle “Type 1” Protype 1937 Deliberately designed to be as simple as possible mechanically, there was simply less that could go wrong; the air-cooled 985 cm³ 25 hp (19 kW) motors proved especially effective in action in North Africa's desert heat. The Beetle evolves By 1938, the "Beetle" shape had fully evolved. A rigorous testing programme was launched, with men of the feared SS driving a batch of the cars for many thousands of miles through the worst winter weather. By 1951, the car was available in 29 countries. 1950 VW Convertible 1935 KdF-Wagen sp. (Porsche) A handful of civilian-specific Beetles were produced, primarily for the Nazi elite, in the years 1940–1945, but production figures were small. Pseudo-Extinction Species (read Boggs, p. 488). Still, this beetle’s lineage lives on. Index Fossil? By 1972, 15,007,034 Produced

11. The Neputinist approach of Werner Abraham Werner (1749-1817) Did not agreed with the theory of the catastrophes of the Cuvier. For him, all the rocks (including the igneous) would have precipitated in a huge global ocean ("neptunisme").

12. Charles Lyell (England; 1797-1875) In furthering Hutton’s magic formula "the present is the key to the past,” Lyell’s book "Principles of Geology" (1830) was a big success. According to him, the geological processes such as the uplift and erosion operated at a slow and uniform speed. Further, every geological period lasted a long time (eventually hundreds of million years) and the age of the Earth must correspond to a multiple of these long lengths. See next slide 

13. (1833) Unlike Will Smith, who used fossils as an aid to identify strata, Lyell (and others at the time) recognized the utility of subdividing the Tertiary on the basis of its fossil content alone. Lyell’s approach was to use the proportions of living and extinct species in the rocks. It is here that fossils became the essential part of subdividing Geologic Time.

14. CONCEPT OF THE BIOZONE (1856) Working in the Jurassic of Europe, Albert Oppel invented the concept of overlapping (aka concurrent) « zones » of fossils and thereby altered for all time the practice of biostratigraphy. An Oppel Zone: Overlapping ranges of two or more taxa Carl Albert Oppel (1831–1865), Germany paleontologist No one since Oppel’s time has been able to devisea more precise and reliable kind of time-stratigraphic fossil zone. Boggs,14.2 Oppel Named his Zones after a particularly distinctive fossil, which he called the Zone’s “Index Fossil.”

15. PRINCIPAL TYPES OF BIOZONES - Range of One -An Overlap of Ranges Add This One! Highest occurrrences (FADs) GAP ZONE -Lowest occurrrences (LADs) Biozones may be grouped or subdivided Gap Biozone - An Assemblage Zone is Different - It’s usually a biogeographic group of three or more taxa Named for one or more distinctive taxa in it

16. Examples of Correlations based on “Taxon-Range Zones” and “Interval Zones” ?

17. LAD D Zone 8 Another Concurrent Range Zone FAD E LAD C C/D Gap Zone LAD B LAD B Concurrent Range Zone FAD C FAD C FAD B A/B Gap Zone LAD A LAD A

18. Abundance Biozones AKA: Acme Zones

19. Time Transgressive Abundance Zones

20. Local vs.Total (Global) Range Species F is different ages in different places? ?

21. Biogeographic Dispersal and Stratigraphic Range Ocean A Barrier Ocean B Time in A Time in B • REMEMBER: • Evolution • Migration • Extinction • Environment • Preservation TOTAL Time in A and B If Total Time is Global, becomes a BIOCHRONOZONE

22. Boggs, 14.8 Correlation by Assemblages Assemblage Zone = Characteristic group of 3 or More Taxa. Commonly, these are environmentally restricted by facies

23. Shaw’s Graphic Correlation Method What can we do here?

24. Shaw’s Method is to plot the heights of the fossil datums in each section versus each other. • Here, the correlation line is straight, meaning there was a constant offset in sediment accumulation rates between the sites • Using the fossil datum correlation line, any part of Section A can be correlated to an equivalent part of Section B.

25. Shaw’s Method is to plot the heights of the fossil datums in each section versus each other. • The point at 50 m in A corresponds in time to the point at 25 m in B. • The point at 50 m in B corresponds to 100 m in A!

26. Shaw’s Method is to plot the heights of the fossil datums in each section versus each other. • The point at 50 m in A corresponds in time to the point at 25 m in B. • The point at 50 m in B corresponds to 100 m in A! So, what exactly is the relative rate of sedimentation between these two sections? Answer: y = mx +b or, rate in A = 2 times rate in B

27. But, what is there if the sedimentation rate changes in one section relative to the other section?What if there are unconformities? Or….

28. “A” speeds up OR “B” slows down Shaw Diagrams to the Rescue! Deposition stops in “A” while continuing in “B” See Nichols, Fig. 20.5

29. A prelude to Oxygen Isotope Stratigraphy: Planktonic Foraminiferal Coiling Ratios Globorotalia truncatulinoides Warm Cold 1.5 Ma

30. TEMPORAL RESOLUTION ISSUES Go Steve Go!

31. RELATIVE STRATIGRAPHIC RESOLUTION BIOCHRONOLOGIC VS RADIOMETRIC DATING 1 Ma Cretaceous Precambrian Miocene Average biochronologic resolution: 1 Ma Typical uncertainty range of radiometric dating: 1% - 10% Biochronological precision exceeds isotopic dating methods for most of Phanerozoic. Isotopic dating, however, is used to calibrate ages of biostratigraphic zones and convert zonal schemes to an equal-interval time scale, an objective that can not be achieved by fossils alone. (From Taylor, A. , 1987, Stratigraphic Resolution)

32. . BioStrat Pau Hana