sedimentary geology

Tuna and Tufo: The geology and history of the Aegadian Islands near Sicily

Hannah Davies March 12, 2026

an image of a sea cove with rugged rocks to the right and bottom right of the image and clear blue sea water to the left and upper left of the image

Cala Rosa, "The red cove", in Favignana, Italy (By giomodica, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=47696822)

The Aegadian or Egadi islands (not to be confused with the Aegean islands situated between present day Greece and Türkiye) is a small archipelago of islands around 20 km off the Western coast of Sicily. These islands are most known for their historic industries, namely for a type of rock quarried from the largest island (Favignana) and the large tuna fishery around the island. In recent times this ...[Read More]

Features from the Field: Angular Unconformities

Samuele Papeschi October 21, 2020

The worldwide famous angular unconformity at Siccar Point, between vertical layers of Silurian graywacke (below) and gently dipping Devonian layers of the Old Red Sandstone Fm. (above). Photo © Dave Souza via Wikimedia.commons

An angular unconformity is an erosional surface that truncates older, tilted sedimentary layers and that is overlain by younger layers, oriented parallel to the unconformity. The discovery and interpretation of angular unconformities, like the famous Hutton’s unconformity at Siccar Point, Scotland, marked a paradigm shift in the geological theories of the 18th century. At that time, the theo ...[Read More]

Features from the field: Bedding/Stratification

Samuele Papeschi December 27, 2019

Inclined bedding planes in Ladakh (India). Photo credits: Arjun Datta (Imaggeo)

Bedding (also called stratification) is one of the most prominent features of sedimentary rocks, which are usually made up of ‘piles’ of layers (called ‘strata‘) of sediments deposited one on top of another. Every stratum is characterized by its own lithology (composition), sedimentary structures, grain size and fossil content that make it unique and different from the stra ...[Read More]