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buy moncler CHAPTER 13 LATE PALEOZOIC HISTORY CHAPTER 13: Late Paleozoic Geology2. The seaways returned again during the Late Carboniferous and deltas became sites of densely wooded swamps that would later be buried and convert into massive coal deposits. 3. The late Paleozoic was a time when the continents assembled to form the supercontinent Moncler Kid Clairy Down Sleeveless Vest Black of Pangea. 4. During the late Carboniferous and Permian, nfl jerseys North America s eastern margin collided with Africa while the southern margin closed against South America. 5. The late Paleozoic sea floor was again abundant in ammonoids, crinoids, bryozoans, corals, molluscs and brachiopods. 6. Land plants continued to diversify in the late Paleozoic moncler outlet such that by mid Permian times, conifers and other primitive seed plants replaced the lowlands coal forests and invaded uplands for the first time. 7. The vertebrates evolved into two main groups, (a) the synapsid lineage which would eventually give rise to the mammals and (b) the reptiles which eventually evolved into turtles, lizards, snakes, crocodiles and dinosaurs during the Mesozoic. 8. Subduction Moncler down jacket blue double-sided camouflage zones flanked much of the perimeters of the great continents. Eastern and southern North America was undergoing (or about to undergo) major collisions with Gondwanaland. 1. Figure 13.3: The early Carboniferous or Mississippian Period (362 322 Ma) was a time when the North American continent was covered by the Kaskaskia epeiric sea as evidenced by extensive marine strata preserved throughout moncler ski wear the craton. 2. All over the world, Mississippian deposits are characterized by thick sequences of limestone. 3. In North America, the Mississippian Period was the last time that widespread carbonate deposition occurred across most of the craton. 4. These carbonate deposits included limestone rich in crinoid fragments in addition to oolite deposits, fossil fragments, cross stratification, ripple marks and scour structures indicative of warm, shallow and often agitated seaways. 5. Reef communities stretched from the southern United States to northern Alaska but they were smaller than Moncler down jackets Women black single-breasted slim the great barrier reef complexes of the middle Paleozoic. Sedimentary and Tectonic Changes 1. During Late Mississippian time, however, distinct changes were occurring in the sedimentation pattern of North America. The pure quartz sandstone characteristic of Early to Middle Paleozoic rocks gave way to more heterogeneous sandstone containing feldspars and micas in addition Moncler Mens jackets goose down Collar Zip Purple to quartz. The heterogeneous sandstone first appeared in the southeastern part of the craton and gradually became more widespread in subsequent periods, attesting to the growing tectonism and deformation around the margins of North America. 2. Warping within the cratonic interior intensified due to the tectonic collisions occurring around the periphery of the continent. 3. The vast Kaskaskian epeiric sea retreated during the Late Mississippian, leaving the continent exposed to extensive erosion that eventually produced a widespread, major unconformity. Similar unconformities also occur on other continents, suggesting that the Late Mississippian regression moncler shopping resulted from a major drop of sea level on a global scale. 4. Figure 13.8: During the Early Pennsylvanian, the North American continent experienced another transgression which led to the deposition of the Absaroka Sequence over the vast erosional surface. 5. The diverse mineralogy of the sediments deposited during this time point to heterogeneous source areas resulting from exhumation and erosion of chiefly igneous and metamorphic rocks which that had been previously been buried beneath early Paleozoic strata but were now exposed. Facies and paleocurrent directions indicate that much of the source area laid in eastern Canada, the site of two major orogenic events (Caledonian and Acadian orogenies). 6. Figure 13.7: Gradual uplift of eastern North America occurred during the Pennsylvianian Period as evidenced by the eastern limits of coarse clastic areas and coal bearing (deltaic) strata. 7. During this same period, the western regions of North America were dumping grounds for pure quartz sediments derived puffer jacket moncler largely from erosion of earlier Paleozoic sandstone located in the west central craton of Canada buy moncler
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