Wednesday, March 21, 2012

Geological Background

The Hajaar Mountains are located along the eastern coast of the Arabian peninsula, predominantly in Oman. The Hajaar is the largest range on the peninsula and boasts the area's tallest mountains. The range was created by tectonic activity in the mid Cretaceous period. A subduction in the ocean floor of the Indian ocean caused the Arabian plate to slide underneath of the Eurasian plate. The result was that a massive amount of oceanic crust and part of the earth's mantle became caked on top of the eastern portion of the Arabian plate. This helps explain why sea shells can be found on top of the tallest peaks around here, most of the range is made of ocean floor!

The main rock type found in oceanic crust Is called ophyolyte which is also the primary rock type found in the Hajaar mountains. The Hajaar has the largest amount of ophyolyte found above sea level anywhere on earth!

After this subduction occurred worldwide ocean levels dropped, exposing the young Hajaar. Along with tons of ophyolyte the range consisted of many soft ocean sediments. Over time water erosion began to form the many peaks and canyons of the Hajaar. While this erosion was occurring, carbonates were also being uplifted due do the widening of the Red Sea. The carbonate rich Arabian plate uplifted through the ophyolyte exposing the Musandam peninsula where I am living. While the majority of the Hajaar is composed of ophyolyte, the Musandam contains very little and is mostly comprised of carbonates.

About 20,000 years ago there were actually glaciers in this region, chiseling away at these carbonates. This carved out deep canyons in some areas and exposed the most solid sheets of rock. It is in these areas that we find the best walls for rock climbing. The rock is smooth, solid, and beautifully featured.

At this point in history, world ocean levels were 120 meters lower than current. This was due to the massive amounts of water stored in glaciers. Once the global temperature rose, the glaciers melted bringing the seas up to the levels of today. Over the course of a few more thousand years the Hajaar experienced some more water erosion as the Arabian peninsula developed its hot arid climate of today.

It now rains an average of 7 days annually here in the Hajaar, so the erosion process has slowed down greatly. However when it does rain the water makes up for the lost time by moving house sized boulders. It is an ever changing environment and the carving of wadis is far from over.
It is thanks to all of this that we now have a beautiful place to climb and explore. May the forces of tectonics and erosion continue to create world class climbing for many generations to come!
From Oman Adventure Season 2012

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