Changes

==Examples of climate==

==Examples of climate==

The total paleolatitudinal range of ancient reefs has been used as a guide to rate of change of sea-surface temperature with paleolatitude. This is based on a broad analogy with the distribution of modern reef corals. Because of the Late Ordovician Gondwana glaciation, the Early Silurian reefs are asymmetrically distributed.<ref name=ch17r28>Copper, P., Brunton, O., 1990, A global review of Silurian reefs: The Palaeontological Association, London, Special Papers in Palaeontology 44, p. 225–259.</ref> They did not reach as far south as 30°S paleolatitude but extended north of 30°N, reflecting the existence of a colder south polar region in the Early Silurian. This conclusion is also supported by the development of a cold-water ''Clarkeia'' province in the Early Silurian of Gondwana<ref name=ch17r25>Cocks, L., 1972, The origin of the Silurian Clarkeia shelly fauna of South America, and its extension to West Africa: Palaeontology, vol. 15, p. 623–630.</ref> which is supplanted at lower latitudes by other faunal provinces.

The total paleolatitudinal range of ancient reefs has been used as a guide to rate of change of sea-surface temperature with paleolatitude. This is based on a broad analogy with the distribution of modern reef corals. Because of the Late Ordovician Gondwana glaciation, the Lower Silurian reefs are asymmetrically distributed.<ref name=ch17r28>Copper, P., Brunton, O., 1990, A global review of Silurian reefs: The Palaeontological Association, London, Special Papers in Palaeontology 44, p. 225–259.</ref> They did not reach as far south as 30°S paleolatitude but extended north of 30°N, reflecting the existence of a colder south polar region in the Early Silurian. This conclusion is also supported by the development of a cold-water ''Clarkeia'' province in the Early Silurian of Gondwana<ref name=ch17r25>Cocks, L., 1972, The origin of the Silurian Clarkeia shelly fauna of South America, and its extension to West Africa: Palaeontology, vol. 15, p. 623–630.</ref> which is supplanted at lower latitudes by other faunal provinces.

Published interpretations of interior Australian surface temperatures during the Permian, reaching values as high as [[temperature::50&deg;C]], cannot be reconciled with the existence of terrestrial vertebrates in the same area because such temperatures would have been lethal. A reassessment of this quantitative model is needed.

Published interpretations of interior Australian surface temperatures during the Permian, reaching values as high as [[temperature::50&deg;C]], cannot be reconciled with the existence of terrestrial vertebrates in the same area because such temperatures would have been lethal. A reassessment of this quantitative model is needed.