Quaternary Period
Quaternary Period
2 to 0 Million Years Ago
Summary The Quaternary Period began about 1.8 million years ago and consists of two epochs: The Pleistocene Epoch, which is 1.8 million to 11,000 years ago, and The Holocene Epoch, which is 11,000 years ago to present. During this time there was very little movement of the continents themselves (Figure 1.3). During this period there were repetitive cycles of cold and warm climate that created the advancing and retreating of ice sheets. The moving of the ice is called glaciation. The evidence of these glacial and interglacial cycles was found in deep sea sediments. These large glaciers molded the land creating lakes and rivers in its path. The temperatures varied greatly between the glacial and interglacial periods. As research shows temperatures affect the wind and ocean currents. This in turn affects the amount of precipitation and dryness around the world. When the glaciers present a land bridge called the Bering Strait (Figure 1.4) between Alaska and Siberia revealed itself. This happened many times during the Quaternary Period. The Bering Strait was most likely how both humans and animals traveled and dispersed themselves throughout the world. During interglacial periods the sea level was higher than it is today. The sea level would lower during periods of glaciation. The lowest the sea level reached was during the Wisconsin Glaciation which put it at 80 meters below its current level. With the cool temperatures and the reoccurring glaciation the temperature of the oceans was near the freezing point. During the early part of the Quaternary Period (The Pleistocene Epoch), there were many large mammals including ground sloths, saber tooth tigers, cave bear, and the dire wolf. The wooly Mammoth (Figure 1.2), mastodon, wooly rhinoceros, reindeer, and musk ox each of utilized a thick coat of fur to help them survive in the cold temperatures. But as temperatures increased the theory is that these species could not
2 to 0 Million Years Ago
Summary The Quaternary Period began about 1.8 million years ago and consists of two epochs: The Pleistocene Epoch, which is 1.8 million to 11,000 years ago, and The Holocene Epoch, which is 11,000 years ago to present. During this time there was very little movement of the continents themselves (Figure 1.3). During this period there were repetitive cycles of cold and warm climate that created the advancing and retreating of ice sheets. The moving of the ice is called glaciation. The evidence of these glacial and interglacial cycles was found in deep sea sediments. These large glaciers molded the land creating lakes and rivers in its path. The temperatures varied greatly between the glacial and interglacial periods. As research shows temperatures affect the wind and ocean currents. This in turn affects the amount of precipitation and dryness around the world. When the glaciers present a land bridge called the Bering Strait (Figure 1.4) between Alaska and Siberia revealed itself. This happened many times during the Quaternary Period. The Bering Strait was most likely how both humans and animals traveled and dispersed themselves throughout the world. During interglacial periods the sea level was higher than it is today. The sea level would lower during periods of glaciation. The lowest the sea level reached was during the Wisconsin Glaciation which put it at 80 meters below its current level. With the cool temperatures and the reoccurring glaciation the temperature of the oceans was near the freezing point. During the early part of the Quaternary Period (The Pleistocene Epoch), there were many large mammals including ground sloths, saber tooth tigers, cave bear, and the dire wolf. The wooly Mammoth (Figure 1.2), mastodon, wooly rhinoceros, reindeer, and musk ox each of utilized a thick coat of fur to help them survive in the cold temperatures. But as temperatures increased the theory is that these species could not