For glaciation to begin, something needs to cause Earth's temperatures to drop. If this happens, snow that falls on the polar ice caps does not melt, and glaciers grow. As snow and ice reflect sunlight, the Earth's temperature is reduced even further, causing glaciers to continue growing.
Sea level changes cause marine transgressions and regressions. During a marine transgression, the shoreline moves inland, leaving sedimentary deposits that contain fossils. The shoreline retreats during a marine regression, leaving behind the deposited sediments.
For glaciation to begin, something needs to cause Earth's temperatures to drop. If this happens, snow that falls on the polar ice caps does not melt, and glaciers grow. As snow and ice reflect sunlight, the Earth's temperature is reduced even further, causing glaciers to continue growing.
Sea level changes cause marine transgressions and regressions. During a marine transgression, the shoreline moves inland, leaving sedimentary deposits that contain fossils. The shoreline retreats during a marine regression, leaving behind the deposited sediments.
