Lake Baikal, located in southeast Siberia, holds the record as the world’s oldest lake, dating back approximately 25 million years. This enormous freshwater body is not only the world’s oldest but also its deepest and most biologically diverse. Measuring 12,239 square miles, it ranks seventh-largest globally.
The lake’s age was determined using isotopic dating, which analyzes radioactive isotopes found in sediments. The sediment layers reveal how old each layer is and how fast they accumulate. Researchers measure cesium, lead, and carbon to determine the lake’s age.
Unlike many lakes, Lake Baikal is a rift lake formed by two continental plates moving apart, creating a graben. This process continues to shape the lake, keeping it open for millions of years. In contrast, glaciers create lakes that are short-lived systems, eventually melting and filling in.
The unique combination of geological features and time has led to an incredible array of flora and fauna endemic to Lake Baikal’s ecosystem. The lake hosts hundreds of species of freshwater shrimp and diatoms, which provide valuable insights into speciation and diversification. Its biologically diverse nature makes it a fascinating subject for researchers like Mark Edlund.
Despite being open to visitors, the lake is not suitable for swimming due to its icy surface temperature, averaging 39 degrees Fahrenheit. Nonetheless, Lake Baikal’s unique characteristics make it an essential discovery in understanding the Earth’s geological history and the persistence of lakes over millions of years.
Source: https://www.livescience.com/planet-earth/whats-the-oldest-lake-on-earth