During the Last Glacial Maximum (LGM), which occurred around 26,500 to 19,000 years ago, glaciers and ice sheets covered vast portions of the Earth's surface. Estimates of glacial ice thickness during this period vary depending on the region and the type of ice sheet. Here's an overview of the estimated ice thickness in key regions during the LGM:
The Laurentide Ice Sheet, which covered much of present-day Canada and parts of the northern United States, had an estimated maximum thickness of around 3,000 to 4,000 meters (9,800 to 13,100 feet) in its central regions, particularly over Hudson Bay. Thickness decreased toward the edges of the ice sheet.
The Fennoscandian Ice Sheet, which covered Scandinavia, the Baltic region, and parts of northern Europe, had estimated maximum thicknesses ranging from 2,000 to 3,000 meters (6,600 to 9,800 feet). The thickest ice was likely centered over what is now southern Sweden and Finland.
The Cordilleran Ice Sheet, which extended over much of western Canada and parts of Alaska, had an estimated maximum thickness of about 1,500 to 2,000 meters (4,900 to 6,600 feet) in its thickest regions, particularly in the mountainous areas.
During the LGM, the Antarctic Ice Sheet was thicker and more extensive than it is today. The estimated maximum thickness in East Antarctica could have reached up to 4,500 meters (14,800 feet), with slightly thinner ice in West Antarctica. The ice sheet extended further onto the continental shelf, contributing to its increased thickness.
The Greenland Ice Sheet was also thicker during the LGM, with estimates suggesting it could have been up to 3,000 meters (9,800 feet) thick in the central regions. The ice sheet covered a larger area than today, particularly along the eastern and western coasts.
The Patagonian Ice Sheet, which covered much of southern Chile and Argentina, had an estimated maximum thickness of around 1,500 to 2,000 meters (4,900 to 6,600 feet), particularly in the Andean region.
These estimates are based on a combination of geological evidence, such as glacial landforms and sediment deposits, as well as computer models that simulate ice sheet behavior during the LGM. The exact thicknesses likely varied due to factors like local topography, climate conditions, and the dynamics of ice flow.