Early Palaeozoic Icehouse


The Early Palaeozoic Icehouse was a cool period that interrupted the greenhouse temperatures of the Ordovician and Silurian periods, This happened in 360MA and led to culminating in the Hirnantian glaciation and the Ordovician extinction event. The icehouse was formerly thought only to consist of the Hirnantian glaciation itself, but has now been recognized as a longer, more gradual event.
Over an interval of 30 million years, seven glacial maxima were recorded in the sedimentary record:
  1. Guttenberg Regression
  2. Early Rakvere Regression
  3. Early Ashgill Regression
  4. Hirnantian Glaciation
  5. Early Ashgill Regression
  6. Early Aeronian Glaciation
  7. Late Telychian Glaciation