Encore - Nahal Perazim Gorge

February 09, 2019

Nahal Perazim walls (4)

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: Menashe Davidson
Summary Author: Menashe Davidson
June 2013 Viewer's Choice
The photo above shows the naturally decorated walls of the Nahal Perazim Gorge. This scenic gorge (wadi) formed over the last 20,000 years or so by fast-flowing water eroding into soft sedimentary rock layers of the Amiaz Plain -- a former lake bed. Corrugations in the horizontal layers give a unique arabesque quality to this barren land. The exposed rock featured here is Lissan Marl (Havar). Bright and dark layers appearing alternately are varves, a word derived from the Swedish word varv that is used to describe seasonal stratification of sedimentary rocks. In general, the varve layer produced in the winter season is thicker, darker and composed of organic sediments; whereas the summer layer is somewhat thinner, brighter and resulted from sedimentation of finer minerals. The varves help indicate the age of the former lake -- like tree rings. Weathering of the rock layers produces a powder called flour. Any visitor here will carry this flour on his or her clothes as a reminder of their visit. Photo taken on April 13, 2013.

Photo Details: Camera: NIKON D80; Focal Length: 31mm (35mm equivalent: 46mm); Aperture: f/14.0; Exposure Time: 0.0050 s (1/200); ISO equiv: 125.  

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