paleogeography

Paleogeography is the study of the past geographic configurations of Earth, including the positions of continents and oceans, coastlines, sea levels, and the distribution of land and sea areas through geological time. It seeks to reconstruct where landmasses and seas were located at different intervals in Earth’s history and how these configurations influenced climate, ocean circulation, biodiversity, and the evolution of life.

The field relies on a range of data and methods. Stratigraphic and lithologic information from rock records provide clues about ancient environments. Fossil assemblages, sedimentary facies, and isotopic signatures help identify past climates, habitats, and sea levels. Magnetostratigraphy and radiometric dating place reconstructions in a temporal framework. The theory of plate tectonics underpins interpretations of continental drift and the arrangement of plates over time. Modern paleogeography often uses computer models and geographic information systems (GIS) to assemble time-sliced maps, or palaeogeographic atlases, that depict past coastlines, ocean gateways, and land bridges.

Applications of paleogeography are broad. It informs understanding of past climate change, sea-level fluctuations, and the distribution of ancient ecosystems; it guides biogeographic and evolutionary studies; and it supports natural-resource exploration by characterizing ancient sedimentary basins and migration routes. Notable examples include reconstructions of supercontinents such as Rodinia, Pangaea, and Gondwana, shifts in ocean basins and gateways, and changes in global climate during events like mass extinctions. Reconstructive maps are hypotheses that improve with new data and methods, reflecting inherent uncertainties in the rock record.