600 Million Years of Cynon Valley
Geological History
by Dr. David. E. Roberts
Contents
1.1 The nature of the Earth’s crust
1.2 Geological Time
1.3 Ancient Geographies
2 The earliest times: the history of the rocks deep below the Cynon Valley
2.1 The Pre-Cambrian
2.1.1 Avalonia
2.2 Avalonia during the Cambrian, Ordovician and Silurian Period
2.3 The Devonian Period
3 Creation of the rocks visible in the Cynon Valley: The Carboniferous Period
3.1 The Carboniferous Limestone
3.2 The Millstone Grit
3.3 The Late Carboniferous
3.3.1 The early sedimentary basins
3.3.2 The Ironstones
3.3.3 The Coal Forming Swamps and Forests
3.3.4 The Pennant Sandstone
3.3.5 The formation of the South Wales Coalfield
3.3.6 The Nature of the Coals and their Formation from Peat
3.7 The Valley's Lost Wealth
4. The Post-Carboniferous History of the Cynon Valley
4.1 The Permian and Triassic Periods
4.2 The Cynon Valley starts to be formed (Triassic to Early Tertiary)
4.3 Later Evolution of the River Cynon
4.3.1 The ancestral River Cynon
4.3.2 River capture by the Afon Nedd and Afon Tawe
4.4 The Pleistocene Ice Ages
4.5 Post Glacial Events