Paleogeography

Paleogeography

Paleogeography. Fossil magnetism in rocks is misaligned with the Earth's present magnetic field, and shows that the continents have moved; it indicates the orientation and latitude of a continent at the time when the rocks were formed. This is the primary source of  information about the past locations of continents, but it gives no indication of longitude. Good evidence of recent movements comes from the growth of ocean floors. Traces of ancient oceans, found among mountains, announce that different pieces of present continents were formerly separated, while evidence of rifting along shore-lines indicates that continents have split asunder. Edges can be put together again by computer programs that reconcile the coarse shapes of continents with the precise geometry of motions on a sphere, to obtain best fit...
The continents can, though, be dismembered into microcontinents, and maps adjusted by evidence of connections and splits between organisms, climate as indicated by characteristic rocks (e.g., coal, or fossil sand dunes), and geological activity. Global patterns of climate and ocean circulation can be inferred...Continental arrangements before 600 My ago are hazy and controversial, although the existence of earlier supercontinents [similar to Pangea] is presumed.

Nigel Calder, Timescale, p.264 (1984, Hogarth Press, London)

Continents and Oceans

Incomplete listing of Continents and Oceans past and present:

Links

Links: Earth History Paleo Map Project - Christopher R. Scotese, one of the definitive refernce sources for paleogeography and paleomaps; Global Regional paleogeographic maps by Ronald Blakey, the other of the two definitive paleogeography and paleomap sites (old site), between them, these two sites get our Best of the Web listing; Paleogeographic Atlas Project Home Page - includes some detailed maps from the Permian and Triassic; The Geological Evolution of the Earth - good overview, period by period; UCMP Glossary: Paleogeography - briefly but usefully lists some important paleocontinents & some geography terms etc, all the UCMP stuff is very good; Paleogeography of the Southwest - interesting page because it has maps alongside text, tracing the changing landmasses, geography, and seas of the SW US throughout the Phanerozoic time; Palaeogeography, Links for Palaeobotanists - comprehensive list of links, but hasn't been updated for a while, so not all are current, part of the excellent "Links for Palaeobotanists" series of pages.

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