Rift lake in the context of "Core sample"

Lake Baikal is a rift lake and the deepest lake in the world. It is situated in southern Siberia, Russia between the federal subjects of Irkutsk Oblast to the northwest and the Republic of Buryatia to the southeast.

At 31,722 km (12,248 sq mi)—slightly larger than Belgium—Lake Baikal is the world's seventh-largest lake by surface area, as well as the second largest lake in Eurasia after the Caspian Sea. However, because it is also the deepest lake, with a maximum depth of 1,642 metres (5,387 feet), Lake Baikal is the world's largest freshwater lake by volume, containing 23,615.39 km (5,670 cu mi) of water or 22–23% of the world's fresh surface water, more than all of the North American Great Lakes combined. It is also the world's oldest lake at 25–30 million years, and among the clearest. It is estimated that the lake contains around 19% of the unfrozen fresh water on the planet.

In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben with normal faulting and rift-flank uplifts mainly on one side. Where rifts remain above sea level they form a rift valley, which may be filled by water forming a rift lake. The axis of the rift area may contain volcanic rocks, and active volcanism is a part of many, but not all, active rift systems.

Major rifts occur along the central axis of most mid-ocean ridges, where new oceanic crust and lithosphere is created along a divergent boundary between two tectonic plates.

Lake Hazar (Turkish: Hazar Gölü; Kurdish: Gola Hezarê; Armenian: Ծովք լիճ, romanized: Covk‘ lič) is a rift lake in the Taurus Mountains, 22 km southeast of Elazığ, notable as the source of the Tigris. Formerly known as Lake Geoljuk, the lake was used as an execution site during the Armenian genocide.

A rift valley is a linear shaped lowland between several highlands or mountain ranges produced by the action of a geologic rift. Rifts are formed as a result of the pulling apart of the lithosphere due to extensional tectonics. The linear depression may subsequently be further deepened by the forces of erosion. More generally the valley is likely to be filled with sedimentary deposits derived from the rift flanks and the surrounding areas. In many cases rift lakes are formed. One of the best known examples of this process is the East African Rift. On Earth, rifts can occur at all elevations, from the sea floor to plateaus and mountain ranges in continental crust or in oceanic crust. They are often associated with a number of adjoining subsidiary or co-extensive valleys, which are typically considered part of the principal rift valley geologically.