Sedimentary Geology Geos 240 – Chapter 5 The Principles of Stratigraphy

2. Sedimentary GeologyGeos 240 – Chapter 5The Principles of Stratigraphy Dr. Tark Hamilton Camosun College

3. Correlation of Stratigraphy • This mainly works for bedded Sedimentary rocks • Correlation of rocks, beds, successions, fossils • Lithology: Lithostratigraphy • Biostratigraphy: widespread but short lived fossils • Chronostratigraphy: zircons, igneous tephra/dyke • Allostratigraphy: unconformity bounded packages • Sequence Stratigraphy: cycles, eustatic, genetic

4. Stratigraphy ofNorthern Ellesmere Island, Nunavut Atlantic Opens Absaroka Series Iapetus Closes (Missing Permian) Kaskaskia Series Bayou-Delta Facies Givetian to Fammenian: Tiktaalik

5. Origins of Stratigraphy: Founders I • ~1550CE Leonardo da Vinci: Tethyan marine fossils in Italian alps • 1669 CE Nicolaus Steno: Original Horizontality, Superposition (younger on top of older beds) • ~1750 CE James Hutton: Uniformitarianism (gradualism), Geological cycles (uplift/tilting, erosion. Sedimentation) & Deep Geological Time • ~1815 CE William Smith: Principle of Faunal Succession, one of earliest Geological maps, Strata of England and Wales

6. Origins of Stratigraphy: Founders II • ~1842 Alcide d’ Orbigny: Biological stages 10 – 100 Ma, evolution based assemblages. Crude biostratigraphy. • ~1856 Albert Oppel: Biologic zones = range of a specific organism, higher resolution biostratigraphy. • ~1917 Joseph Barrell: Base level or sea level changes will result in breaks (unconformities) genetic strat. • 1963 Larry Sloss: Subaerial unconformities bound stratigraphic sequences. Allostratigraphy • ~1960’s Harry Wheeler:Time distance diagrams: duration, extent and hiatus in strat. Sequences • 1977 Peter Vail:Global Eustatic Sea Level changes & Global correlations on seismic strat. Who needs biostrat, local basins?

7. William “Strata” Smith: 1769-1839 • Principal of Stratigraphic Association of Fossils (faunal succession) • 1815 1st Geological Map of England • Canal Surveyor • 1st Wollaston Medalist of the Geological Society of London

8. Cross Section of London BasinJerome Harrison, 1882 Following in the footsteps of William “Strata” Smith

9. Correlation of Stratigraphy • Comparing & connecting stratigraphic successions between localities: trenches, cliffs, boreholes or across and between basins • Lithology: Lithostratigraphy, Original Triassic, 3 distinctive beds across the Alps. (Alberti’s Trias referred to the division of these strata into three units: the Bunter [or Buntsandstein], Muschelkalk (Limes), and Keuper (Marls), known as the “Germanic facies,” is mainly Continental. The type sections are now more widespread Marine facies based on ammonoids.

10. Muschelkalk-Keuper Boundary:Winterswijk Netherlands: H.W. Oosterink et al 2006 Marls/Black Clays Rhaetian/Liassic Muschelkalk Limestones (Buntsandstein Unexposed)

11. Correlation of Stratigraphy • Biostratigraphy: widespread but short lived fossils • Relative ages requires statistical numbers of fossils • Only good to +/- 1Ma (the average species lifespan) • Chronostratigraphy • Absolute radiometric dates from: zircons, apatites, igneous events, tephra-ash beds, U-Pb or 39Ar/40Ar • Magnetic Reversal Stratigraphy ≤ Cretaceous • Marine Stable Isotope: H/D, 16O/18O, 32S/34S, 12C/13C • Allostratigraphy: unconformity bounded packages • Sequence Stratigraphy: cycles, eustatic, genetic

12. 1800’s Faunal Succession & Correlation: Stephanoceras and Micraster Lower Jurassic (Midlands) & Upper Cretaceous ChalkAmmonite (Cephalopoda) & Echinoid (Heart Urchin, Echinodermata)

13. Biostratigraphy • Dozens to hundreds of species • Gradual structural changes  evolution • Biozones (time), Stages (evolutionary differentiation) • Picky species nail the environment, quiet, rough, O2 • FAD: First occurrence datum • Coincident Range (Concurrent species) • LAD: Last Occurrence Datum • Biocenose assemblages (living ecologies) • Thanatocenose assemblages (enviro-accumulations)

14. Chronostratigraphy • Post WWII, Harold Urey, U.Chicago, Solid Source Mass Specs, 238U  206Pb, 87Rb 87Sr & 87Sr/ 86Sr, Deuterium, Precambrian Atmosphere, Nobel Prize • Thermochronometry, Derek York U of T : Lunar rocks, Ar-39/40, thermal blocking temperatures

15. Chronostratigraphy: Radio-isotopes • U/Pb clocks from Zircon & Baddeleyite for Precambrian sediments, igneous cores & meta rims • Rb/Sr for intercalated Volcanics or feldspars for Mesozoic and older rocks (due to long half life and low Rb/Sr ratio) • K/Ar for Pliocene and older Volcanics • 39/40Ar some sedimentary minerals like Glauconite or Fission Track for Pleistocene and older Volcanics • Disequilibrium Uranium series isotopes (Ra for Ca) for Pleistocene & older Carbonates, reefs, speleothems • Radioactive fallout correlation dating: 137Cs, 90Sr

16. Allostratigraphy (Larry Sloss, 1963) • Major Unconformities bound packages of stratigraphy which correlate across and between continents • Caused by tectonic and global eustatic events, 10-100 Ma long for North America: • Zuni • Absaroka • Kaskaskia • Tippecanoe • Sauk • Later Peter Vail of Exxon extended this to the Atlantic Basin mainly on eustatics alone & Seismic Sequence Stratigraphy

17. Stratigraphic Variability for a Hypothetical Lithostratigraphy

18. Relative Datum flattened Shale line to right edge Log Shape Analysis: Wiggle Matching SP or Resistivity

19. 2 Methods of Defining Stratigraphy Ordovician Cambrian Paleocene (Tertiary) Maastrictian (Cretaceous) Cow Head Breccia: Green Point Newfoundland K/T Boundary Clay, Frenchman Valley, Saskatchewan A) Nothing Happened orB) Widespread Distinctive Event

21. Zuni Absaroka Kaskaskia Tippecanoe Sauk

22. Allostratigraphic Breaks in Rift BasinFormations are Lithostratigraphic

23. Subdivision of Regional Cambro-Ordovician Strata: by Litho & Allostrat. Tippecanoe is Upper Ordovician – Silurian over Sauk = Upper Cambrian – Middle Ordovician

24. Biozones

25. Biozones: Maastrichtian Chalk NW Europe # = Species Concurrent Range Biozones