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

Fossils Biostratigraphy: 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

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

Charles Darwin EVOLUTION RATES? Gradual Rapid A. Phyletic gradualism Gradual Morphology Schematic ‘family tree’ (body characteristics) B. Punctuated equilibrium Boggs 14.1.1 Charles Darwin Rapid Morphology (body characteristics) Schematic ‘family tree’ In punctuated model, speciation occurs only1000s (100s?) yrs, after population becomes reproductively isolated from the parent population.

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) "System of nature through the three kingdoms of nature, according to classes, orders, genera and species. This was a subdivision of his Three Kingdoms: Animal, Plant and Mineral. Linnaeus was a Swedish MD, In view of the popularity of the work Linnaeus kept publishing new and ever expanding editions, growing from eleven pages in the first edition (1735) to three thousand pages in the final and thirteenth edition (1770)! Carolus Linnaeus after BOGGS, 14.5

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. Boggs 14.1

Methodology INDEX INDEX FOSSILS ARE: FOSSILS: independent of environment short range widespread INDEX FOSSILS: Important Marine Forms of the Phanerozoic Boggs 14.6. From Tenius, 1973, Fossils and the Life of the Past, Fig. 50 (Wpinger-Verlag). Nichols has the same as Figure 20.2 without giving credit white bars show total range; black bars show times when imp. Index fossil.

The Finer Points of Stratigraphy

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

INDEX FOSSILS: independent of environment short range widespread “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

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").

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. Boggs, Table 14.1 Lyell’s Subdivisons of the Tertiary See next slide 

(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.

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 devise a more precise and reliable kind of time-stratigraphic fossil zone. Oppel’s Concept of Overlapping biozones forever changed geology. Each of Oppel’s zones were named after a key species, termed an Index Fossil Boggs,14.2 Oppel Named his Zones after a particularly distinctive fossil, which he called the Zone’s “Index Fossil.”

PRINCIPAL TYPES OF BIOZONES Biozones may be grouped or subdivided - 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 Boggs 14.3 Types of Biozones

Correlations based on “Taxon-Range Zones” and “Interval Zones” Examples of Correlations based on “Taxon-Range Zones” and “Interval Zones” Boggs, 14.11 ?

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

Abundance Biozones AKA: Acme Zones Boggs Fig. 14.4

Time Transgressive Abundance Zones Boggs 14.10

Species F is different ages in different places? Local vs.Total (Global) Range Species F is different ages in different places? ? Boggs 14.7

If Total Time is Global, becomes a 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

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

Shaw’s Graphic Correlation Method What can we do here? Boggs Fig. 14.12 Shaw’s Method of Graphical Correlation Between Section. Comin up is the Determination of Sedimentation Rates

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. Boggs Fig. 14.12 Shaw’s Method of Graphical Correlation Between Section. Comin up is the Determination of Sedimentation Rates

The point at 50 m in A corresponds in time to the point at 25 m in B. 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! Boggs Fig. 14.12 Shaw’s Method of Graphical Correlation Between Section. Comin up is the Determination of Sedimentation Rates

The point at 50 m in A corresponds in time to the point at 25 m in B. 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? Boggs Fig. 14.12 Shaw’s Method of Graphical Correlation Between Section. Comin up is the Determination of Sedimentation Rates Answer: y = mx +b or, rate in A = 2 times rate in B

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

Shaw Diagrams to the Rescue! “A” speeds up OR “B” slows down Shaw Diagrams to the Rescue! Boggs Fig. 14.4 Deposition stops in “A” while continuing in “B” See Nichols, Fig. 20.5

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

TEMPORAL RESOLUTION ISSUES Boggs Table 14.1 Go Steve Go!

Average biochronologic resolution: 1 Ma 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)

. BioStrat Pau Hana