Paleozoic and Mesozoic Seas
Paleozoic and Mesozoic Seas
Earth’s oceans were full of life during the Paleozoic and Mesozoic eras. In the Paleozoic Era, 541 to 252 million years ago…
The Mesozoic Era, meaning the middle life of Earth's history, was a time when seas were filled with marine creatures like the mosasaurus, and dinosaurs roamed the land. This era is also known as the Age of Dinosaurs.
During this time, the planet experienced events called marine transgressions and regressions, which refer to the rise and fall of sea levels over time.
A marine transgression occurs when the sea level rises, flooding the land and creating more water-covered areas. This happens when land sinks because of tectonic activity or when water volume increases due to melting glaciers or seafloor spreading.
Conversely, a marine regression occurs when the sea level falls, exposing land that was previously underwater. This can result from land rising during mountain-building events or a decrease in water volume as glaciers grow, trapping water as ice.
We can see evidence of these events in characteristic rock layers called sedimentary facies. Nearshore rocks may contain sand or pebbles, while deeper regions preserve fine sediments like shale or limestone, revealing past environments.
The Mesozoic Era, meaning the middle life of Earth's history, was a time when seas were filled with marine creatures like the mosasaurus, and dinosaurs roamed the land. This era is also known as the Age of Dinosaurs.
During this time, the planet experienced events called marine transgressions and regressions, which refer to the rise and fall of sea levels over time.
A marine transgression occurs when the sea level rises, flooding the land and creating more water-covered areas. This happens when land sinks because of tectonic activity or when water volume increases due to melting glaciers or seafloor spreading.
Conversely, a marine regression occurs when the sea level falls, exposing land that was previously underwater. This can result from land rising during mountain-building events or a decrease in water volume as glaciers grow, trapping water as ice.
We can see evidence of these events in characteristic rock layers called sedimentary facies. Nearshore rocks may contain sand or pebbles, while deeper regions preserve fine sediments like shale or limestone, revealing past environments.
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