Sediment

Sediments such as marine sediment, lake sediment, and loess (wind sediment) provide us with additional information. These sediments are found in layers and gradually accumulate. Cores of these sediments may give the following information:

• Strata in loess provide us with data about changes in temperature and precipitation. Grain size gives information about wind velocity and direction.
• Accumulation rate of lake sediment provides us with information about rainfall. Grain size of sediment and pollen composition gives us indications of rainfall and temperatures.
• Marine sediment cores provide us with information about ocean currents, ocean temperatures, salinity changes and glacial cycles. Glacial marine sediment, because of its lithogenous (derived from rock) unsorted nature, is easy to detect. Sediment types provide us with information about the history of marine life in the area, which, in turn, gives us indications of temperature, salinity and currents.

Sediments give us information about the earth's climate millions of years ago, up to 20 million years ago in the case of marine sediment. However, the resolution (ability to pinpoint the exact time) of this information is rarely less than hundreds of years.

Back to Exploring Clues to Our Past.