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Late Paleozoic Earth History

Chapter 11. Late Paleozoic Earth History. Tully Monster. Tullimonstrum gregarium, also known as the Tully Monster is Illinois’s official state fossil Specimen from Pensylvanian rocks, Mazon Cree Locality, Illinois. Reconstruction of the Tully Monster about 30 cm long. Mazon Creek Fossils.

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Late Paleozoic Earth History

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  1. Chapter 11 Late Paleozoic Earth History

  2. Tully Monster • Tullimonstrum gregarium, also known as the Tully Monster is Illinois’s official state fossil • Specimen from Pensylvanian rocks, Mazon Cree Locality, Illinois • Reconstruction of the Tully Monster • about 30 cm long

  3. Mazon Creek Fossils • Approximately 300 million years ago • in the region of present-day Illinois, • sluggish rivers flowed southwestward through swamps, • and built large deltas that extended outward into a subtropical shallow sea • These rivers deposited high quantities of mud • that entombed many of the plants and animals living in the area • Rapid burial • and the formation of ironstone concretions • preserved many of the plants and animals of the area

  4. Exceptional Preservation • The resulting fossils, • known as the Maxon Creek fossils • for the area in northeastern Illinois • where most specimens are found, • provide us with significant insights about the soft-part anatomy of the region's biota • Because of the exceptional preservation of this ancient biota, • Mazon Creek fossils are known throughout the world • and many museums have extensive collections from the area

  5. Pennsylvanian Delta Organisms • During Pennsylvanian time, two major habitats existed in northeastern Illinois • One was a swampy forested lowland of the subaerial delta, • and the other was the shallow-marine environment of the actively prograding delta • Living in the warm, shallow waters • of the delta front were numerous • cnidarians, • mollusks, • echinoderms, • arthropods, • worms, • and fish

  6. Swampy Lowlands • The swampy lowlands surrounding the delta were home to more than 400 plant species, • numerous insects, • including millipedes and centipedes, as well as spiders • and other animals such as • scorpions and amphibians • In the ponds, lakes, and rivers were many • fish, shrimp, and ostracodes • Almost all of the plants were • seedless vascular plants, • typical of the kinds that lived in the coal-forming swamps • during the Pennsylvanian Period

  7. Tully Monster • One of the more interesting Mazon Creek fossils is the Tully Monster, • which is not only unique to Illinois, • but also is its official state fossil • Named for Francis Tully, • who first discovered it in 1958, • Tullimonstrum gregarium • its scientific name • was a small • up to 30 cm long • soft-bodied animal that lived in the warm, shallow seas • covering Illinois about 300 million years ago

  8. Tully Monster • The Tully Monster had a relatively long proboscis • that contained a "claw" with small teeth in it • The round-to-oval shaped body was segmented • and contained a cross-bar, • whose ends were swollen, • and are interpreted by some to be the animals sense organs • The tail had two horizontal fins • It probably swam like an eel • with most of the undulatory movement occurring behind the two sense organs

  9. Tully Monster • There presently is no consensus • as to what phylum the Tully Monster belongs • or to what animals it might be related

  10. Tully Monster • Tullimonstrum gregarium, also known as the Tully Monster is Illinois’s official state fossil • Specimen from Pensylvanian rocks, Mazon Cree Locality, Illinois • Reconstruction of the Tully Monster • about 30 cm long

  11. Late Paleozoic Paleogeography • The Late Paleozoic was a time of • continental collisions, • mountain building, • fluctuating seas levels, • and varied climates • Coals, evaporites, and tillites • testify to the variety of climatic conditions • experienced by the different continents during the Late Paleozoic

  12. Gondwana Continental Glaciers • Major glacial-interglacial intervals • occurred throughout much of Gondwana • as it continued moving over the South Pole • during the Late Mississippian to Early Permian • The growth and retreat of continental glaciers • during this time • profoundly affected the world's biota • as well as contributing to global sea-level changes

  13. Continental Collisions • Collisions between continents • not only led to the formation of the supercontinent Pangaea • by the end of the Permian, • but resulted in mountain building • that strongly influenced oceanic and atmospheric circulation patterns • By the end of the Paleozoic, • widespread arid and semiarid conditions prevailed over much of Pangaea

  14. The Devonian Period • During the Silurian, • Laurentia and Baltica collided along a convergent plate boundary • to form the larger continent of Laurasia • This collision, • which closed the northern Iapetus Ocean, • is marked by the Caledonian orogeny • During the Devonian, • as the southern Iapetus Ocean narrowed • between Laurasia and Gondwana, • mountain building continued along the eastern margin of Laurasia • with the Acadian orogeny

  15. Paleogeography of the World • For the Late Devonian Period

  16. Paleogeography of the World • For the Early Carboniferous Period

  17. Paleogeography of the World • For the Late Carboniferous Period

  18. Paleogeography of the World • For the Late Permian Period

  19. Reddish Fluvial Sediments • The erosion of the resulting highlands • provided vast amounts of reddish fluvial sediments • that covered large areas of northern Europe • Old Red Sandstone • and eastern North America • the Catskill Delta

  20. Collision of Laurentia and Baltica • Other Devonian tectonic events include, • the Cordilleran Antler orogeny, • the Ellesmere orogeny along the northern margin of Laurentia • which may reflect the collision of Laurentia with Siberia • and the change from a passive continental margin to an active convergent plate boundary • in the Uralian mobile belt of eastern Baltica • These are probably related to the collision of Laurentia and Baltica

  21. Uniform Global Climate • The distribution of • reefs, • evaporites, • and red beds, • as well as the existence of similar floras throughout the world, • suggests a rather uniform global climate during the Devonian Period

  22. The Carboniferous Period • During the Carboniferous Period • southern Gondwana moved over the South Pole, • resulting in extensive continental glaciation • The advance and retreat of these glaciers • produced global changes in sea level • that affected sedimentation pattern on the cratons • As Gondwana continued moving northward, • it first collided with Laurasia • during the Early Carboniferous • and continued suturing with it during the rest of the Carboniferous

  23. Gondwana/Laurasia Collision • Because Gondwana rotated clockwise relative to Laurasia, • deformation of the two continents generally progressed in a northeast-to-southwest direction along • the Hercynian, • Appalachian, • and Ouachita mobile belts • The final phase of collision between Gondwana and Laurasia • is indicated by the Ouachita Mountains of Oklahoma • which were formed by thrusting • during the Late Carboniferous and Early Permian

  24. Pangaea Began Taking Shape • Elsewhere, Siberia collided with Kazakhstania • and moved toward the Uralian margin of Laurasia (Baltica), • colliding with it during the Early Permian • The northwestern margin of China may have • collided with the southwestern margin of Siberia • during the Late Carboniferous • By the end of the Carboniferous, • the various continental landmasses were fairly close together • as Pangaea began taking shape

  25. Coal Basins in Equatorial Zone • The Carboniferous coal basins of • eastern North America, • western Europe, • and the Donets Basin of Ukraine • all lay in the equatorial zone, • where rainfall was high and temperatures were consistently warm • The absence of strong seasonal growth rings • in fossil plants from these coal basins • is indicative of such a climate

  26. Fossil Plants of Siberia • The fossil plants found in the coals of Siberia, • however, show well-developed growth rings, • signifying seasonal growth • with abundant rainfall • and distinct seasons • such as occur in the temperate zones • at latitudes 40 degrees to 60 degrees north

  27. Continental Ice Sheets • Glacial condition • and the movement of large continental ice sheets • in the high southern latitudes • are indicated by widespread tillites • and glacial striations in southern Gondwana • These ice sheets spread toward the equator and, • at their maximum growth, • extended well into the middle temperate latitudes

  28. The Permian Period • The assembly of Pangaea • was essentially completed during the Permian • as a result of the many continental collisions • that began during the Carboniferous • Although geologists generally agree • on the configuration and locations • of the western half of the supercontinent, • no consensus exists • on the number or configuration of the various terranes • and continental blocks that composed the eastern half of Pangaea

  29. Pangaea Surrounded • Regardless of the exact configuration • of the eastern portion of Pangaea, • geologists know that the supercontinent • was surrounded by various subduction zones • and moved steadily northward during the Permian • Furthermore, an enormous single ocean, • Panthalassa, • surrounded Pangaea and • spanned Earth from pole to pole

  30. Climatic Consequences • The formation of a single large landmass • had climatic consequences for the continent • Terrestrial Permian sediments indicate • that arid and semiarid conditions were widespread over Pangaea • The mountain ranges produced by • the Hercynian, Alleghenian, and Ouachita orogenies • were high enough to create rain shadows • that blocked the moist, subtropical, easterly winds • much as the southern Andes Mountains do in western South America today

  31. Mountains Influenced Climate • The mountains’ influence produced very dry conditions in North America and Europe, • as evident from the extensive • Permian red beds and evaporites • found in western North America, central Europe, and parts of Russia • Permian coals, • indicative of abundant rainfall, • were mostly limited to the northern temperate belts • latitude 40 degrees to 60 degrees north • while the last remnants of the Carboniferous ice sheets retreated

  32. Late Paleozoic History of North America • The Late Paleozoic cratonic history of North America included periods • of extensive shallow-marine carbonate deposition • and large coal-forming swamps • as well as dry, evaporite-forming terrestrial conditions • Cratonic events largely resulted from changes in sea level due to • Gondwanan glaciation • and tectonic events related to the joining of Pangaea

  33. Mountain Building • Mountain building • that began with the Ordovician Taconic orogeny • continued with the • Caledonian, • Acadian, • Alleghenian, • and Ouachita orogenies • These orogenies were part of the global tectonic process • that resulted in the formation of Pangaea by the end of the Paleozoic Era

  34. The Kaskaskia Sequence • The boundary between • the Tippecanoe sequence (discussed previously) • and the overlying Kaskaskia sequence • Middle Devonian-Middle Mississippian • is marked by a major unconformity • As the Kaskaskia Sea transgressed • over the low relief landscape of the craton, • the majority of the basal beds deposited • consisted of clean, well-sorted quartz sandstones

  35. Oriskany Sandstone • A good example is the Oriskany Sandstone • of New York and Pennsylvania • and its lateral equivalents • The Oriskany Sandstone, • like the basal Tippecanoe St. Peter Sandstone, • is an important glass sand • as well as a good gas-reservoir rock

  36. Basal Kaskaskia Sandstones • Extent of the basal units of the Kaskaskia sequence in the eastern and north-central United States

  37. Source Areas • The source areas for the basal Kaskaskia sandstones • were primarily the eroding highlands of the Appalachian mobile belt area, • exhumed Cambrian and Ordovician sandstones cropping out along the flanks of the Ozark Dome, • and exposures of the Canadian Shield in the Wisconsin area

  38. Devonian Period • Paleogeography of North America during the Devonian Period

  39. Sediment Sources • The earlier Silurian carbonate beds • below the Tippecanoe-Kaskaskia unconformity • lacked Kaskaskia-like sands • The absence of such sands indicates • that the source areas for the basal Kaskaskia • had still been submerged and not yet exposed at the time the Tippecanoe sequence was deposited • Stratigraphic studies indicate • that these source areas were uplifted • and the Tippecanoe carbonates removed by erosion • prior to the Kaskaskia transgression

  40. Kaskaskian Rocks • Kaskaskian basal rocks • elsewhere on the craton • consist of carbonates • that are frequently difficult to differentiate • from the underlying Tippecanoe carbonates • unless they are fossiliferous • The majority of Kaskaskian rocks are • carbonates, including reefs, and associated evaporite deposits • except for widespread Upper Devonian and Lower Mississippian black shales

  41. Other Parts of the World • In many other parts of the world, such as • southern England, • Belgium, • Central Europe, • Australia, • and Russia, • the Middle and early Late Devonian epochs were times of major reef building

  42. Reef Development in Western Canada • The Middle and Late Devonian-age reefs of western Canada • contain large reserves of petroleum • and have been widely studied from outcrops and in the subsurface • These reefs began forming • as the Kaskaskia Sea transgressed southward • into Western Canada

  43. Middle Devonian Reefs and Evaporites • By the end of the Middle Devonian, • the reefs had coalesced into a large barrier-reef system • that restricted the flow of oceanic water into the back-reef platform, • thus creating conditions for evaporite precipitation • In the back reef area, up to 300 m of evaporites • were precipitated in much the same way as in the Michigan Basin during the Silurian

  44. Devonian Reef Complex • Reconstruction of the extensive Devonian Reef complex of western Canada • These reefs controlled the regional facies of the Devonian epeiric seas

  45. Potash from Evaporites • More than half of the world's potash, • which is used in fertilizers, • comes from these Devonian evaporites • By the middle of the Late Devonian, • reef growth stopped in the western Canada region, • although nonreef carbonate deposition continued

  46. Black Shales • In North America, many areas of carbonate-evaporite deposition • gave way to a greater proportion of shales • and coarser detrital rocks • beginning in the Middle Devonian and continuing into the Late Devonian • This change to detrital deposition • resulted from the formation of new source areas • brought on by the mountain-building activity • associated with the Acadian orogeny in North America

  47. Increased Detrital Deposition • Deposition of black shales • was brought on by the the Acadian orogeny

  48. Widespread Black Shales • As the Devonian Period ended, • a conspicuous change in sedimentation took place over the North American craton • with the appearance of widespread black shales • These Upper Devonian-Lower Mississippian black shales are typically • noncalcareous, • thinly bedded, • and usually less than 10 m thick

  49. Extent of Black Shales • The extent of the upper Devonian and Lower Mississippian Chattanooga Shale and its equivalent units • such as the Antrion Shale and the Albany Shale

  50. New Albany Shale • Upper Devonian New Albany Shale, • Button Mold Knob Quarry, Kentucky

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