Encore - Folded Rock on the Portuguese Vicentine Coast

August 22, 2020


Today and every Saturday Earth Science Picture of the Day invites you to rediscover favorites from the past. Saturday posts feature an EPOD that was chosen by viewers like you in our monthly Viewers' Choice polls. Join us as we look back at these intriguing and captivating images.

Photographer: Maria de Lurdes Fonseca
Summary Authors: Maria de Lurdes Fonseca; Stu Witmer

October 2014 Viewer's Choice Seen above is an excellent example of folded rock on the Portuguese Vicentine coast near Almograve. Folded rocks once were stratified, horizontal layers of sediment that have become warped or folded when compressed. Being sedimentary, the oldest rocks are at the bottom of the stack while the youngest are on top. In the example above the youngest rock is in the middle of the V and the oldest is at the apex, here buried by sand. This particular arrangement is called a syncline. Near the bottom right of the image you’ll note that the rock layers arch over like an upside-down U. This is called an anticline with the older layers in the middle. Some folds encompass entire mountain ranges and often occur where tectonic plates collide. The Alps, Andes, Himalayas and the Rocky Mountains are all folded mountain ranges. Photo taken August 27, 2014.

Photo Details: Camera SONY DSC-W810; Focal Length: 4.6mm (35mm equivalent: 26mm); Aperture: f/3.5; Exposure Time: 0.0080 s (1/125); ISO equiv: 100; Software: Adobe Photoshop 7.0.