The Late Wisconsin Glaciation, the most recent major advance of continental ice sheets in North America, occurred during the Last Glacial Maximum (LGM) approximately 26,500 to 19,000 years ago. In Alaska, this period saw significant glaciation, though not as extensive as in some other parts of North America. Here are the details regarding the Late Wisconsin glaciation in Alaska:
1. Cordilleran Ice Sheet:
The Cordilleran Ice Sheet was a prominent feature in Alaska during the Late Wisconsin glaciation.
It covered the southeastern part of Alaska, including areas around the present-day Alaska Panhandle and extending into the coastal regions of British Columbia.
The ice thickness was substantial, often reaching 1.5 to 2 kilometers (about 0.9 to 1.2 miles) in some areas, particularly in mountainous regions.
2. Mountain Glaciers:
The Alaska Range, the Chugach Mountains, the Kenai Mountains, the Brooks Range, and other highland areas had extensive valley glaciers and ice caps.
These glaciers were thick, with some valley glaciers extending down to sea level, creating fjords and glacial valleys.
Ice thickness in these mountainous areas could range from several hundred meters to over a kilometer in the most heavily glaciated regions.
3. Interior and Northern Alaska:
Central and northern Alaska were less affected by the continental ice sheets.
The region was characterized by permafrost and tundra rather than extensive ice sheets, with smaller, isolated glaciers in some mountainous regions.
This area remained largely ice-free, creating conditions for unique ecological zones and providing pathways for animal and human migration.
4. Bering Land Bridge:
The Bering Land Bridge, exposed due to lower sea levels, connected Alaska with Siberia.
This land bridge was largely ice-free, serving as a migration route between Asia and North America for plants, animals, and early human populations.
5. Coastal and Fjord Regions:
The coastal areas of southern Alaska were heavily glaciated, with glaciers extending from the mountains down to the ocean, carving out fjords and depositing moraines.
These coastal glaciers were often thick, with significant ice flow into the ocean, contributing to today's glacial landscapes.
During the Late Wisconsin glaciation, Alaska's glacial coverage was complex, influenced by local topography and broader climatic conditions. The combination of extensive mountain glaciers, significant ice sheets in the southeast, and relatively ice-free interior regions created a diverse and dynamic glacial environment.