Stratigraphy DEFINITION OF STRATIGRAPHY DEFINITION OF STRATIGRAPHY 1. Branch of geology that deals with definition & description of major & minor natural division of rocks... w/ the interpretation of their significance in geologic history. 1. Branch of geology that deals with definition & description of major & minor natural division of rocks... w/ the interpretation of their significance in geologic history. 2. Specifically, the geologic study of the form, arrangement, geographic distribution, chronological succession, classification & esp. correlation and mutual relationships of rock strata in normal sequence. 2. Specifically, the geologic study of the form, arrangement, geographic distribution, chronological succession, classification & esp. correlation and mutual relationships of rock strata in normal sequence. 3. It involves interpretation of these features of rock strata in terms of origin, occurrence, environment, thickness, lithology, composition, fossil content, age, history, paleogeography etc 3. It involves interpretation of these features of rock strata in terms of origin, occurrence, environment, thickness, lithology, composition, fossil content, age, history, paleogeography etc

Introduction A. Beginning- (~1500AD) da Vinci saw fossils in rks of Italian Apennines Concluded fossils once living marine organisms Concluded fossils once living marine organisms

Introduction B. Steno important contributor Principle of Original Horizontality Principle of Original Horizontality Principle of Superposition Principle of Superposition Principle of Lateral Continuity Principle of Lateral Continuity

Steno Principles Lateral Continuity Superposition Original Horizontality

Development of Sed Strat as Science Organization of sed rocks—Arduino ( ) divided rocks Organization of sed rocks—Arduino ( ) divided rocks Primary Mtns- metallic ores no fossils Primary Mtns- metallic ores no fossils Secondary Mtns- Stratified, lithified, fossiliferous, no fossils Secondary Mtns- Stratified, lithified, fossiliferous, no fossils Tertiary low Mtns- Fossiliferous, unconsolidated gravels, sands clay, volcanics Tertiary low Mtns- Fossiliferous, unconsolidated gravels, sands clay, volcanics Alluvium- Sediment washed down from mtns Alluvium- Sediment washed down from mtns

Development of Sed Strat as Science Geologic Cycle and Uniformitarianism Geologic Cycle and Uniformitarianism James Hutton ( )-Scottish Physician, farmer James Hutton ( )-Scottish Physician, farmer  Noted cyclicity to earth’s behavior  Uplift, erosion, transport, deposition  Established Principle of Uniformitarianism or Actualism present key to past but rates change and catastrophes occur present key to past but rates change and catastrophes occur

Development of Sed Strat as Science – Birth of Biostratigraphy & Stratigraphic Correlation William Smith( )-English surveyor, engineer  “father” of biostratigraphy  Canal builder noted relationship of fossils & rocks  Established law of faunal succession—fossils succeed each other in organized & recognizable fashion  Produced first geologic map gsahist.org

Birth of Biostratigraphy & Stratigraphic Correlation  D’Orbigny (1842)- developed biologic stage for rock division  strata systematically follow each other with characteristic fossil assemblage  Oppel (1856)- developed biologic zone  Rocks deposited during existence of specific fossil  Zones based of first appearance of last appearance of organisms  Zones could be correlated

Oppel Zones

Development of Sed Strat as Science Petrographic microscope development Petrographic microscope development Sorby began microscopic study of rocks Sorby began microscopic study of rocks Led to description and systematic study of rocks Led to description and systematic study of rocks Geologic Revolution- Seafloor Spreading and Plate Tectonics Geologic Revolution- Seafloor Spreading and Plate Tectonics s- Renaissance period s- Renaissance period More funds, more geophysical exploration, Deep Sea Drilling Project More funds, more geophysical exploration, Deep Sea Drilling Project More oil exploration More oil exploration

New Tools New Tools Magnetic and Seismic Surveying Magnetic and Seismic Surveying Identification of normal/reverse periods led to magnetostratigraphy Identification of normal/reverse periods led to magnetostratigraphy Seismic surveying could identify units and unconformities, packages of related rocks Seismic surveying could identify units and unconformities, packages of related rocks Isotope stratigraphy Isotope stratigraphy Use carbon and oxygen isotopes to correlate units Use carbon and oxygen isotopes to correlate units petroleum-gas.blogspot.com

Magnetostratigraphy sp.lyellcollection.org

Seismic Stratigraphy www-odp.tamu.edu

Development of Sed Strat as Science Sedimentary Rocks and Earth History Sedimentary Rocks and Earth History Paleoclimate Paleoclimate study of ancient climate study of ancient climate

Development of Sed Strat as Science Sedimentary Rocks and Earth History Sedimentary Rocks and Earth History Paleogeography Paleogeography reconstruction of area for given time in past reconstruction of area for given time in past Wiley.com

Development of Sed Strat as Science Sedimentary Rocks and Earth History Sedimentary Rocks and Earth History Paleoecology & Evolution Paleoecology & Evolution studies relationships between ancient organisms & their environments studies relationships between ancient organisms & their environments jpg

Development of Sed Strat as Science Sedimentary Rocks and Earth History Sedimentary Rocks and Earth History Paleoceanography & Ancient Atmosphere Paleoceanography & Ancient Atmosphere Composition of ancient oceans and atmosphere using isotopes Composition of ancient oceans and atmosphere using isotopes