Natural History Photographs

When landmasses collide, the lithosphere shortens and thickens. Horizontal layers of sediments are compressed and folded, giving rise to arch-like shapes called anticlines (which have the oldest beds in their core) and synclines (with younger layers closer to the center of the structure). Asymmetric forces may overturn the folds, so that their orientation no longer is vertical.

Anticline at Durbuy, Belgium; 8 June 2013.

Anticlinal structure near Düzağaç (Antalya), Turkey; 3 May 2014.

Angular folds near Agios Paulos, Crete; 3 & 5 April 2018. The layers consist of limestone with dark siliceous intercalations, formed between the Jurassic and Eocene periods.

Cascada del Sorrosal, Broto, Spain; 22 October 2018.
Various fold patterns are exposed through the erosion caused by the waterfall.

The Boltaña anticline in the Spanish Pyrenees; 20 October 2018.

Dismantled small-scale fold structure. Janovas (Huesca), Spain; 20 October 2018.

Overturned fold structure near Torla (Huesca), Spain; 22 October 2018.