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Dr. Tark Hamilton Camosun College
Sedimentary Geology Geos 240 – Chapter 5 The Principles of Stratigraphy Dr. Tark Hamilton Camosun College
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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
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Stratigraphy of Northern Ellesmere Island, Nunavut
Atlantic Opens Absaroka Series Iapetus Closes (Missing Permian) GSA Bulletin; November 1976; v. 87; no. 11; p ; DOI: / (1976)87<1599:DGOBIA>2.0.CO;2 © 1976 Geological Society of America This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by MIALL, A. D. Search for Related Content GeoRef GeoRef Citation Devonian geology of Banks Island, Arctic Canada, and its bearing on the tectonic development of the circum-Arctic region ANDREW D. MIALL1 Kaskaskia Series Bayou-Delta Facies Givetian to Fammenian: Tiktaalik
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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
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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?
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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
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Cross Section of London Basin Jerome Harrison, 1882
Following in the footsteps of William “Strata” Smith
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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.
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Muschelkalk-Keuper Boundary: Winterswijk Netherlands: H. W
Muschelkalk-Keuper Boundary: Winterswijk Netherlands: H.W. Oosterink et al 2006 Marls/Black Clays Rhaetian/Liassic Triassic sat between the better known Permian of the Continental Redbeds of the Zechsandstein (Zechstein Basin) and overlying fully Marine Jurassic. Originally a lithostratigraphic definition by Alberti in the German Alps for the succession Beige Sandstone overlain by White Limestone and finally by Black Marls. The disruption of these beds is due to Quaternary solution collapse in the underlying gypsum beds of the Permian Section (well below the level of the quarry and surface exposures). Muschelkalk Limestones (Buntsandstein Unexposed)
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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
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1800’s Faunal Succession & Correlation: Stephanoceras and Micraster Lower Jurassic (Midlands) & Upper Cretaceous Chalk Ammonite (Cephalopoda) & Echinoid (Heart Urchin, Echinodermata)
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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)
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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
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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 Many of these techniques require special lithologies or minerals which aren’t present in all sedimentary beds. Ergo we can only bracket stratigraphy.
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Allostratigraphy (Larry Sloss, 1963)
Major Unconformities bound packages of stratigraphy which correlate across and between continents Caused by tectonic and global eustatic events, 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 See p.264
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Stratigraphic Variability for a Hypothetical Lithostratigraphy
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Shale line to right edge
Relative Datum flattened Shale line to right edge Log Shape Analysis: Wiggle Matching SP or Resistivity
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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 or B) Widespread Distinctive Event
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Porous Gassy “Milk River” Sandstones: Shallow Cretaceous Gas Play in Southern Alberta, Western Canada Basin using Gamma Ray and an Electrical Resistivity Log. The high resistivity is due to the gas displacing the brine, making a resistive layer, with the classical signature of a “gas sand”. The 1st White Specks is a Volcanic Ash Marker Bed, Back arc K rich ash with enough Se to cause birth defects if you drink from this horizon!
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Zuni Absaroka Kaskaskia Tippecanoe Sauk
Wheeler Diagram for N.Am. Interior: Zuni, Absaroka, Kaskaskia, Tippecanoe, Sauk Note that the US Cordillera is missing the Proterozoic and Triassic through Jurassic Tippecanoe Sauk
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Allostratigraphic Breaks in Rift Basin Formations are Lithostratigraphic
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Subdivision of Regional Cambro-Ordovician Strata: by Litho & Allostrat.
Most strata are limestones and dolostones with interbedded sandstones and shales. (Jeeze there must have been some exposed shield around somewhere to the NW, Eh?) Tippecanoe is Upper Ordovician – Silurian over Sauk = Upper Cambrian – Middle Ordovician
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Biozones Since Albert Oppel’s introduction of the concept for the range of a single species, this concept has grown to include temporal assemblages defined by tens to hundreds of species. Since DSDP & ODP work on Cretaceous through Modern marine microfossils the resolution is now about 1Ma. There remain regional disparities. Walter Blow’s Carribbean succession and stages clashes with Bolli’s definitions in the Mediterranean and this is even for Planktonic Foraminifera. There is also problem in tying Terrestrial facies to Marine Records as young as the Pleistocene Holocene boundary. Mammoths and Forams seldom partied together! Which type section do we use?
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Biozones: Maastrichtian Chalk NW Europe
Concurrent Range Biozones # = Species Concurrent Range Biozones
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Siccar Point
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