Studies of depth sensitive carbonate successions in the UK indicate that regular, orbitally forced glacio-eustatic sea-level oscillations, which characterized the late Palaeozoic, started abruptly around 330 Ma (early Asbian). The Gondwanan ice sheet was highly sensitive to orbitally forced variations in solar insolation and the resultant sea-level oscillations had an approximate 100 ka periodicity. Studies of fossil soils and palaeokarst from low latitude settings suggest that pre-Asbian climates were relatively stable with infrequent changes. However, climatic changes became increasingly frequent in the Asbian and Brigantian, with regular fluctuations of a sub-100 ka periodicity occurring during glacial lowstand intervals.
Scientific editing by Duncan Pirrie.
- Received October 26, 2000.
- Accepted January 14, 2001.
- © 2001 The Geological Society of London