EXTREMELY IMPORTANT:
This EC will show you a wonderful hidden gem that can be one of the highlights of your trip to Oman and that will teach how caves inside rivers that flow through sedimentary rock are created.
It is important to remember that you will be inside a mountain canyon that can be very dangerous in case of rain.
You must be very aware that you cannot enter it under any circumstances if it has rained in the last two days or if rain is forecast, not only in the nearby area, but in the entire region. Flash floods are very common in this part of the world and can be deadly.
Neither the author of this EC nor Geocaching can be held responsible for any accidents that occur during the resolution of this EC. Please, bear in mind that you are accessing the canyon at your own risk and discretion.
A canyon is a deep, narrow valley with steep sides. “Canyon” comes from the Spanish word cañón, which means “tube” or “pipe.” The term “gorge” is often used to mean “canyon,” but a gorge is almost always steeper and narrower than a canyon.
A cove is a small, sheltered bay or recess in a canyon or coastline, often formed by erosion. In sedimentary canyons, coves develop when softer rock layers erode faster than harder rock layers, creating bowl-shaped depressions. These formations provide valuable insights into the geological history of an area, revealing the processes of weathering, erosion, and sediment deposition over time.
Sedimentary rock is the most common type in the world. It is created by a 5 episodes process:
- Erosion: Rocks are eroded (by water, wind, impact of other rocks…) or weathered (by chemical agents, ice, changes of temperature…) into smaller pieces called sediments.
- Transportation: Eroded sediments end up in the water and begin to settle down.
- Deposition: With time, more sediments are added to newly formed sedimentary layers.
- Compaction: The release of moisture from the sedimentary layers makes the layers compact.
- Cementation: Salt crystals glue the layers to form more compact sedimentary rocks.
Sedimentary canyons form over millions of years through the erosion of layered sedimentary rocks, such as sandstone, limestone, and shale. Coves within these canyons often develop where softer rock layers erode more quickly than harder, more resistant layers above them. This results in a semicircular or amphitheatre-shaped indentation within the canyon walls.
Key geological processes involved include:
- Differential Erosion: Varying resistance to erosion creates coves where softer rock is worn away more rapidly.
- Water Erosion: Rivers and flash floods carve into the canyon walls, widening existing coves over time.
- Weathering: Physical and chemical weathering contribute to the breakdown of rock, enhancing cove formation.
- Mass Wasting: Rockfalls and landslides can expand coves as material collapses from above.
LOGGING TASKS:
To log this EC, go to the given coordinates (inside the inner cove), answer the following questions and send them to us using the message service. Afterwards, you can log it.
- What types of sediment layers are visible in the inner cove (the one with the deep pool). Describe their appearance.
- You are now standing at one of the most beautiful coves that a river can create. Explain in your own words which of the key geological processes you can observe in the inner cave.
- If water is present, how is it affecting the formation of the cove?
- As a proof that you have been in the cove, please attach a photo of you (you can blur your face) or a photo of your nickname. Logs without the required photo will be deleted.
HOW TO GET THERE:
The cave is located at the end of Wadi Ghul, one of the most spectacular valleys in the country. To access it, you must drive along a track of about 7 km until you reach a village called Wadi Nakhr, starting from the place indicated on the given access waypoint. You will need a 4-wheel drive vehicle with a gear reduction.
Once you are in Wadi Nakhr, you must follow the three-colour marks painted on the rock, which are the ones that usually indicate mountain trails in Oman.
Although the excursion is not excessively difficult, you must bear in mind that you must climb two sections of a fairly vertical wall with the help of "clamps" nailed to the wall, similar to those of via ferratas. These sections are quite short, however. They do not exceed 10 meters. The total gain in elevation is of about 200 meters. Do not rely on GPS readings.
This is a good description of the hike: https://ca.wikiloc.com/rutes-senderisme/wadi-al-nakhar-200749261
