Olifantsnek has a lot of significance to the people in this area. It provides access between the Highveld and Bushveld, it has a historic significance dating back to the stone age and more recently was crucial to the escape of the Boer Pimpernel, General De Wet during the second Anglo Boer War. Water resources for agriculture, nature conservation and recreation are all incorporated in this area. We will hopefully now learn a little about the geography of this area.
NOTE: DO NOT ATTEMPT THIS EC UNLESS YOU ARE TRAVELING IN THE DIRECTION FROM RUSTENBURG TO KRUGERSDORP.
ACCESS TO THE SAFE PARKING AREA IS ONLY FROM THIS DIRECTION.
The Magaliesberg Range has a very long geological history. Its quartzites, shales, chert and dolomite were deposited as sediments in an inland basin on top of the 3 billion year old Archaean Basement Complex. This process of sedimentation lasted for about 300 million years. About 2 billion years ago a massive upwelling of molten magma resulted in what is now known as the Bushveld Igneous Complex. The enormous weight of this intrusion depressed the sediments that lay beneath and tilted the sediments along the edges so that the broken scarps faced outward and upward, and the gentler dip slopes inward. During the same period these sediments were fractured and igneous intrusions of dolerite filled the cracks. With the passage of time these intrusions eroded, especially on the dip slopes, forming deep kloofs or ravines providing excellent rock-climbing potential to modern man. This large dog-leg-shaped area is now termed the Transvaal Basin and includes the lofty escarpment of the Transvaal Drakensberg overlooking the Lowveld in the eastern part of the country. Massive outpourings of igneous material - volcanic lava - of the much younger Karoo Supergroup later covered the Transvaal Basin, but this was subsequently eroded so that it only remains along the Transvaal Basin's southern rim.
This parking area gives you a good spot to get out the car and have a look at the two significant features for this earthcache – namely the Nek and the Poort.
This point marks a spot in the Magaliesberg mountains where movement from the HIGHVELD (Magaliesburg, Derby, Boons and Potchefstroom) to the BUSHVELD (Rustenburg, Brits, Marikana and Sun City). The gap in the mountains allows not just man and animals to pass easily, but it is also the lowest spot so water and air move through here too as the path of least resistance (you may well experience a strong breeze as you stop).
So the area you need to observe are the two (2) low points on the mountain range - where the road is and where the river is.
Your Tasks
In order to substantiate your visit and be able to claim this EarthCache a number of questions need to be answered and submitted to the cache developer, via e-mail, to “cincolcc [at] gmail.com”
1 – In your own words explain what you think the difference is between a “nek” and a “poort”
2 – Look at the nek that you have just traveled through and look at the poort where the dam wall has been build. Describe them and what differences between the 2 that you can observe.
3 – Based on your answer above do you think these 2 features were formed by the same forces? Why do you say this?
4 – Describe any other interesting things you saw or experiences you had on site (you can add these to your log for others to enjoy too). Photos are always welcomed in the logs.
NOTE: You may log your visit prior to approval, but e-mail submissions that do not meet the above criteria will be deleted.
