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How did lower sea levels during the Pleistocene expose continental shelves?

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continental shelf The broad, gentle pitch of the continental shelf gives way to the relatively steep continental slope. The more gradual transition to the abyssal plain is a sediment-filled region called the continental rise. The continental shelf, slope, and rise are collectively called the continental margin.

During the Pleistocene Epoch, the exposure of continental shelves was primarily driven by global eustatic sea-level changes resulting from major glacial advances.1

As continental glaciers expanded, vast quantities of water that would normally reside in the oceans were locked up as ice on land. This process caused a significant drop in global sea levels—at times of maximum glaciation, such as 18,000 years ago, sea levels were more than 100 metres (328 feet) lower than they are today.12

When the sea level fell below the shelf break, the continental shelves were transformed into subaerial environments. These exposed areas were then subjected to weathering, soil formation, and fluvial and eolian activity, and they became habitable for plants and animals. This exposure created land bridges, such as the one that connected Siberia to Alaska via the Bering Shelf, facilitating intercontinental migration. As glaciers subsequently retreated, the melting ice returned water to the ocean basins, causing sea levels to rise and resubmerge these coastal environments.312