Exercise 4:
Ice sheets and glaciers can tell scientists a lot about geological history. They can reveal information about the sea level changes and climatic changes of the Earth's past. Layer by layer the ice sheet builds up over time, preserving a record of precipitation patterns, temperatures, and atmospheric gases or particles. There are some layers of ice in Antarctica that hold over 250,000 years worth of climatic information.

Since scientists cannot study the entire ice sheet, they collect ice core samples. Another unit, focusing on sediments, describes how sediment core samples are collected by ocean drilling vessels from the bottom of the ocean floor. Similiarly, cores of ice are drilled out of the ice shelves in Antarctica. The sediments and gases within the ice cores are then studied to learn more about climatic, oceanic, and geologic history.

In this photo, an ice core is being removed from a drilling pipe. By studying this core's composition, much can be learned about past of the climate, atmosphere, and oceans.