Biostratigraphy Geology 331 Paleontology The Grand Canyon of the Colorado River in Arizona Lithostratigraphic correlation between Grand Canyon, Zion, and Bryce Canyon national parks allows construction of a composite stratigraphic column. Lithostratigraphic correlation Grand Canyon, Zion Canyon, Bryce Canyon between Grand Canyon, Zion, and Bryce Canyon national parks Top of Navaho Ss. allows construction of a Top of Kaibab Ls. composite stratigraphic column. Zion Canyon National Park, Jurassic Sedimentary Rocks Jurassic Navaho Sandstone, Zion National Park, wind-blown cross-bedding. Bryce Canyon, Utah, Cretaceous sedimentary rocks Correlation • Determination of the equivalence of bodies of rock at different locations. There are two kinds of correlation: • Lithostratigraphic - matching up continuous formations. • Chronostratigraphic - matching up rocks of the same age. Usually done with fossils using biostratigraphy. Correlation • Over short distances lithostratigraphic correlation is the same as chronostratigraphic correlation. • Over medium distances they are not the same. • Over long distances only chronostratigraphic correlation can be used. Original Lateral Continuity: permits lithostratigraphic correlation – note the continuous beds Lithostratigraphic and Chronostratigraphic Relationships Sedimentary facies, and their subsequent rocks, are usually time-transgressive. http://www.geol.umd.edu/~tholtz/G331/lectures/331strat.html Sedimentary Facies Modern Barrier Island Time Lines Sedimentary Facies in the subsurface Wire line logs Time Lines Modern Barrier Island Sedimentary Facies in the subsurface WireLewis line Shalelogs Parkman Ss Cody Shale Simple Lithostratigraphic Correlation: Facies Boundaries, not Time Lines Correlation Using Fossils Grand Canyon Stratigraphy Correlated Bed contacts Detailed lithostratigraphic correlation of the Cambrian strata of the Grand Canyon. Note the facies interfingering. Interfingering of strata due to shifting of facies during deposition Zone of middle Cambrian trilobites Zone of early Cambrian trilobites Cambrian strata of the Grand Canyon: Note the two time lines from biostratigraphy. Time lines established by biostratigraphy Depositional Model for the Cambrian strata of the Grand Canyon: Tapeats Sandstone, Bright Angel Shale, and Muav Limestone Transgression, regression, and stratigraphic cycles 1 4 2 3 Taxon Range Zone: Between a FAD and a LAD for a given species http://www.geol.umd.edu/~tholtz/G331/lectures/331strat.html Concurrent Range Zone: FAD on Sp. D, LAD on Sp. B http://www.geol.umd.edu/~tholtz/G331/lectures/331strat.html Interval Zone: Between two successive FADs or LADs http://www.geol.umd.edu/~tholtz/G331/lectures/331strat.html Hedberg and Salvador, 1994 http://www.stratigraphy.org/ upload/bak/bio.htm Hedberg and Salvador, 1994 http://www.stratigraphy.org/ upload/bak/bio.htm Ranges may or may not be concurrent. Hedberg and Salvador, 1994 http://www.stratigraphy.org/ upload/bak/bio.htm Not commonly used. Can be diachronous. Examples of Local Range Zones (connect the dots) http://geoweb.princeton.edu/people/keller/deccan/large/Fig9_Gov_Q_biost_col.jpg geoweb.princeton.edu/.../massex.html Forams and Diatoms Ammonites Cretaceous Biozones based on microfossils and ammonites http://paleopolis.rediris.es/cg/CG2009 _A03/CG2009_A03_Fig_01.htm Phylum Mollusca, Class Cephaplopoda, a goniatitic ammonoid with a simple suture pattern Phylum Mollusca, Class Cephaplopoda, a ceratitic ammonoid with a more complex suture Phylum Mollusca, Class Cephaplopoda, an ammonitic ammonoid with the most complex suture Trilobites are the best index fossils for the Cambrian. Conodont Taxon Range Zones in the Mississippian. Conodonts range from Ordovician to Triassic. http://www.kgs.ku.edu/Publications/Bulletins/165_1/index.html Examples of conodonts, the teeth of primitive chordates The conodont animal from the Mississippian of Scotland 1 cm Conodont Biozones for the Ordovician http://australianmuseum.net.au/image/Stratigraphic- range-and-diversity-of-conodonts/ Conodont Biozones for the Ordovician http://australianmuseum.net.au/image/Stratigraphic- range-and-diversity-of-conodonts/ Examples of Biozones based on Graptolites and Conodonts Graptolites Journal of Paleontology; January 2003; v. 77; no. 1; p. 146-171 Putting Radiometric Dates on Biozones: Previous Example from Radiometric Dating Lecture .