Last Ice Age
The Last Glacial Period (often colloquially referred to as the Last Ice Age) was the most recent glacial period of the current Ice Age (the Quaternary glaciation). It spanned from approximately 115,000 to 11,700 years ago, ending with the onset of the current Holocene interglacial.
Chronology
- Onset: ~115,000 years ago (Eemian Interglacial termination).
- Last Glacial Maximum (LGM): ~26,500–19,000 years ago, characterized by maximum ice sheet expansion.
- Deglacialiation: Rapid warming and ice retreat between 19,000 and 11,700 years ago.
- Termination: ~11,700 years ago (Younger Dryas conclusion), marking the start of the Holocene.
Characteristics
- Sea Levels: Global sea levels dropped by ~120-130 meters, exposing land bridges such as Beringia.
- Climate: Global average temperatures were ~5-10°C lower than pre-industrial levels; arid conditions dominated many regions.
- Vegetation: Expansion of Tundra and steppe environments; boreal forests retreated to refugia.
Megafauna and Extinction Events
The period supported large Pleistocene megafauna populations. The extinction of these species occurred in waves, largely correlating with human expansion and climatic shifts at the end of the glacial period.
- Woolly Mammoth (Mammuthus primigenius):
- Mainland populations persisted until ~4,000 years ago on Wrangel Island.
- St. Paul’s Island Population: Isolated populations survived significantly longer on St. Paul’s Island (Alaska). See detailed analysis in St. Paul’s Island Woolly Mammoth Extinction: Chronology and Causes.
- Represents the second-to-last known mammoth extinction event.
- Extinction driven by resource competition and habitat loss during post-glacial transgression.
Related Concepts
- Quaternary Glaciation
- Younger Dryas
- Bering Land Bridge
- Pleistocene Megafauna