A huge, catastrophic rock fall occurred 4,500 years ago in the high Atlas Mountains, Morocco. The timing of this event has been determined using exposure-age dating. The collapse of the northwest face of Mount Aksoual, which reaches a height of nearly 13,000 ft (4000 m), caused large-scale landscape change. the rock fall represents one of the biggest recorded in Africa and sits below a cliff face 6500 ft (2000 m) high, close to an active tectonic fault. Today, a village sits precariously on this huge mass of boulders.
Early to Middle Ordovician back-arc basin in the southern Appalachian Blue Ridge: Characteristics, extent, and tectonic significance
James Tull et al., Florida State University, Earth Ocean and Atmospheric Science, Tallahassee, Florida 32306-4520, USA. Published online 20 Mar. 2014; http://dx.doi.org/10.1130/B30967.1.
This paper by James Tull and colleagues links the stratigraphy and tectonic history of a large segment of the southern Appalachian Blue Ridge and adjacent areas in Alabama, Georgia, and North and South Carolina to a common tectonic setting: formation within an Ordovician (about 480 to 460 million years ago) proto-North American (Laurentian) back-arc basin. The tectonic setting suggested by this study indicates that the Taconic (early to middle Ordovician time) orogeny in the southernmost Appalachians differs from that in the northern Appalachians, and began as an extensional accretionary orogen along the outer margin of the Laurentian continent, rather than resulting from an exotic (non-Laurentian) arc collisional setting.
Analogue modeling of positive inversion tectonics along differently oriented pre-thrusting normal faults: An application to the Central-Northern Apennines of
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Geological Society of America