The physical geography of the Devonian can be reconstructed using evidence from paleomagnetism, paleoclimate, paleobiogeography, and tectonic events. Because the paleomagnetic data for the Devonian is conflicting, recent efforts to describe the positions of the continents have concentrated on the rock types associated with particular environments. Such methods focus on the distribution of evaporites, shelf carbonates, and corals because present-day deposits of these types have specific, well-known climatic constraints. Faunal distributions are also employed but to a lesser extent.
There is general agreement that the paleoequator crossed the northern part of Laurussia during the Devonian. Paleomagnetic evidence, however, is not clear, and various positions for the exact placement of the paleoequator have been proposed. Though Laurussia was essentially tropical or subtropical, its climatic zones changed somewhat through the course of the Devonian as this landmass migrated northward during Late Devonian and Early Carboniferous times. Evidence for this movement includes the reduction in evaporitic environments in western Canada and the onset of humid and moist conditions in the area of New York.
The southern continents of today were united into the supercontinent of Gondwana during the Devonian approximately along the lines of their present-day continental shelf boundaries. Establishing the position of Gondwana is more difficult than for Laurussia. Some interpretations favour a wide ocean separating these two large landmasses, but this arrangement is thought to be unlikely because of the remarkable occurrences of similar corals, brachiopods, and ammonites in eastern North America, Morocco, and Spain. Yet, even if these areas were close together, their precise positioning is not certain. Based on the similarity in fossils, some researchers would place North Africa adjacent to the eastern North American seaboard during this period. The late Devonian reef developments in Western Australia suggest a near tropical site for this portion of the southern landmass. The positions of the microcontinents that later came together to form Asia are rather uncertain, but many of them probably were either attached or adjacent to the northern margin of Gondwana and migrated north to fuse with the growing area of Asia at several junctures during the later Phanerozoic Eon.
Paleomagnetic evidence is inconsistent regarding the position of the South Pole. Though some researchers postulate a location in central South America, most favour a position south of central Africa or off its southeast coast. The North Pole was in the ocean.
There is general agreement that the paleoequator crossed the northern part of Laurussia during the Devonian. Paleomagnetic evidence, however, is not clear, and various positions for the exact placement of the paleoequator have been proposed. Though Laurussia was essentially tropical or subtropical, its climatic zones changed somewhat through the course of the Devonian as this landmass migrated northward during Late Devonian and Early Carboniferous times. Evidence for this movement includes the reduction in evaporitic environments in western Canada and the onset of humid and moist conditions in the area of New York.
The southern continents of today were united into the supercontinent of Gondwana during the Devonian approximately along the lines of their present-day continental shelf boundaries. Establishing the position of Gondwana is more difficult than for Laurussia. Some interpretations favour a wide ocean separating these two large landmasses, but this arrangement is thought to be unlikely because of the remarkable occurrences of similar corals, brachiopods, and ammonites in eastern North America, Morocco, and Spain. Yet, even if these areas were close together, their precise positioning is not certain. Based on the similarity in fossils, some researchers would place North Africa adjacent to the eastern North American seaboard during this period. The late Devonian reef developments in Western Australia suggest a near tropical site for this portion of the southern landmass. The positions of the microcontinents that later came together to form Asia are rather uncertain, but many of them probably were either attached or adjacent to the northern margin of Gondwana and migrated north to fuse with the growing area of Asia at several junctures during the later Phanerozoic Eon.
Paleomagnetic evidence is inconsistent regarding the position of the South Pole. Though some researchers postulate a location in central South America, most favour a position south of central Africa or off its southeast coast. The North Pole was in the ocean.
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