FOLDING
Parts of a fold (see p.47)
A. Anticline (upfolds)
B. Syncline (downfolds)
Types of folds (see p.47)
A. Simple/Symmetric
B. Asymmetric
C. Overfold
D. Overthrust fold
E. Chevron fold
Case Study
The Munster ridge and valley region
-350-400 million years ago huge amounts of sand were deposited in the south and southwest
of Ireland
-This formed a rock that we call Old Red Sandstone
-Later a muddy sea covered the area and limestone formed on top of the sandstone
-300 million years ago the plates collided and fold mountains (amorican folding) were
formed
-These mountains stretch from Waterford to Kerry e.g. Comeraghs, Silvermines and the
Galtees.
-The top of the mountains are made of resistant (tough) sandstone rock because the limestone
that once covered them was eroded.
-The limestone in the valleys (synclines) was not eroded and still remains e.g. in Blackwater
valley and Golden Vale
-This has led to the region being called the Munster Ridge and Valley Region
Fold Mountain Building (Orogeny) in Ireland
A. Caledonian Folding
-400 million years ago
-E.g. Leinster Mountains
B. Amorican Folding
-300 million years ago
-Munster Ridge and Valley Region
C. Alpine Folding
-50 million years ago
-Too young to be found in Ireland
-E.g. Alps and Himalayas