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How do warm-adapted plant fossils reveal the extent of Jurassic tropical climates?

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Jurassic paleogeography — Jurassic Period Distribution of landmasses, mountainous regions, shallow seas, and deep ocean basins during the late Jurassic Period. Included in the paleogeographic reconstruction are the locations of the interval's subduction zones.

Fossils of warm-adapted plants provide significant evidence for the climate of the Jurassic Period. The discovery of these fossil remains as far as 60° N and 60° S paleolatitude indicates that the tropical zone was much more expansive during this time than it is today.1

The presence of these plants, alongside ferns and other frost-sensitive species in higher paleolatitudes, suggests that the temperature difference between the Equator and the poles was significantly less severe than in the modern era. This decreased latitudinal temperature gradient, likely supported by the distribution of warm waters by the Tethys Sea, contributed to a generally warm global climate without evidence of polar ice caps or glaciation. While gymnosperms—such as cycads and conifers—dominated the terrestrial ecosystem, the widespread distribution of these warm-adapted floras serves as a key indicator of the period's reduced climatic extremes.12