Geology Photos 1: Folds and Faults

Geology Photos 1: Folds and Faults
Geology Photos 2: Sedimentary Rock and Structures
Geology Photos 3: Fossils
Geology Photos 4: Igneous Rocks

Folds and Faults

Gently folded Carboniferous limestone at Scarlett. This folding probably occurred during the Variscan mountain-building event approximately 290 million years ago.
These very contorted layers are small folds within the Manx Group at Niarbyl.
The broad curving surface in the middle of the photo is a layer of sediment that was originally horizontal. Some 410 million years ago, these beds were trapped between converging continents during the Caledonian mountain-building event, producing large folds like these ones within the Dalby Group, Peel Hill.
This fault, which has white quartz along it, separates the Ordovician Manx Group (around 470 million years old) from the Silurian Dalby Group (around 425 million years old). These two groups of sediments were eroded from continents on opposite sides of the Iapetus Ocean.
This view shows Peel in the low-lying area with Peel Hill behind it. Peel has been built on approximately 380 million year old Peel sandstone while the rocks that make up Peel Hill are part of the much older 425 million years old Dalby Group. In most circumstances, younger sediments should appear above older ones but around Peel, the younger Peel sandstones have been dropped down by a large fault which runs N-S, parallel to the ridge of hills in the distance, so that they now lie next to each other.