Alex B. answered • 02/25/24
Experienced HS Geoscience Educator at a Highly Ranked STEM School
We use the knowledge of the climate that we find current plant and animal species at and apply that to the past. So, for instance, if we find a fossil of a leaf from a palm tree, we know that the climate of that location on Earth at that time period had to be warm since we find palm trees today in warm climates. A great example of that is in Antarctica. A scientific team back in 2012 drilled through 1 kilometer of sediment and retrieved sediment that was 53 million years old. In the sediment, there were pollen grains from palm trees. This tells us that Antarctica 53 million years ago was a lot warmer than the Antarctica that we know today. The example of sediment from Antarctica is not a fossil, but the same concept applies.
We can use similar concepts in the rock record even if there are no fossils. There were rocks discovered in India that had markings on them called striations. Striations on rocks are only created in areas where there are glaciers. We know that glaciers form either in areas near the poles or areas with very high elevations. Through lots of research and collaboration, it was decided that the rocks with striations in India had to have been far from the equator at the time the striations were left on the rocks. This helped with Alfred Wegener's continental drift hypothesis, where he argued that there once was a supercontinent on Earth, which he called Pangea. Pangea occupied the southern hemisphere near the south pole.
