The underlying geology of Kruger Park is predominantly basal and granite, where the granite is interspersed with gabbro. Shale and sand deposits are fairly minimal and widely dispersed. Rhyolite occurs in a thin band making up the Lebombo Mountains that form the eastern border between Kruger Park and Mozambique.
Basalt is darker and is composed of magnesium and iron, whereas granite is lighter and is made up of feldspar and quartz. 
Igneous rocks are classified based on their chemical composition from granite to basalt. With the exception of potassium, rocks of granite composition contain relatively low concentrations of essential plant nutrients. In comparison, rocks of basalt composition contain much higher nutrient concentrations of iron, magnesium, calcium, and several other trace elements. Thus, soils formed on basalt are inherently more fertile than a comparable soil formed on granite.
In Southern Africa, basaltic landscapes are generally regarded as nutrient rich and granite as nutrient poor. Granitic landscapes also have a lower clay content compared to basaltic ones.Termites require clay for nest, however, too much clay can cause soil to become water logged and prone to cracking, becoming unconducive to termite mounds nesting. Despite this higher soil nutrient status on basalts, termite diversity is higher on granites, the mounds are larger and cover a greater area of the landscape, it can therefore be concluded that termite diversity is highly influenced by soil type, with nutrient poor soils having higher levels of termite diversity.
Kruger's very slow erosion rates mean that the soils from crests to channels have been stable for very long periods of time. Even very slow movements of material downslope have left their distinctive imprint in the landscape. So what kinds of materials move over time?
The smallest materials may represent individual molecules of water, but in the dry climate of Kruger, many of these molecules fail to move very far in the soil because much of the water that rains down on Kruger is evaporated or transpired by trees. It is estimated that these losses of water range from three to four times the amount of rain falling across Kruger.This imbalance between losses and additions of water is a defining characteristic of savannas and helps explain the great variability in the soil landscape. It is neither too dry for things to wash slowly downslope as in the Kalahari, nor too wet, when water just washes everything away. Kruger, and the lowveld in general, are in just the right place to form well-differentiated soil landscapes.
If some of the smallest materials slowly moving downslope are water molecules, what other materials are slowly being washed downhill toward the rivers crossing the park? These large rivers are ultimately responsible for carrying small pieces of Kruger through the Lebombo Mountains to the Indian Ocean. These small materials include salts such as sodium ions and clay-sized particles. Remember that the reason the oceans are salty is that, over time, the breakdown of rock frees salts that were once trapped in the rock. In wetter parts of the world with metres of rain (versus Kruger's half metre), the release of salt from rock, and the transport of that salt to the ocean, occurs extremely quickly.
Here in Kruger, that two-step sequence of breaking away and transport occurs slowly enough to lead to great soil variability from crest to channel. How exactly is sodium liberated from rock? One way to think about this is to imagine a rock sitting in a bath of acid.
That acid dissolves the rock, freeing elements that make up the rock, including sodium. Rock under soil is bathed in acid. Most of the acid is produced by soil organisms and plant roots, although Kruger is receiving more and more acid via its rainfall because of the large concentration of power plants upwind. The characteristic termite mounds that punctuate the horizon are important producers of acidity.
The next time you see a termite mound, think about it as an acidity pump, injecting acid deep into the soil, where it meets the granite rock and begins a sodium ion on its long odyssey to the Indian Ocean.
Termite mounds are islands of food and moisture that are very attractive to animals and seed growth. Good tree growth provides attractive habitat for more animals which deposit more nutrients - and thus an island of high activity is created - all started by the termites.
Old termite mounds are used by a variety of reptiles and small mammals, such as mongooses, and the dispersing nutrients enrich the surrounding grasses for large ungulates
Afsaal was a camp site used by 19th century transport riders. Today it is a picnic spot with a restraunt. One of the main features at this picnic spot is the massive termite mound with a giant Jackalberry tree growing out of it.
To qualify for this Earth Cache please answer the following questions:
1) Post a picture of yourself/team with Termitarium in the background (optional)
2 )Based on what you can see at the GZ and the information above, do you think the area you are standing at Basaltic or Granitic type soil and why?
3) On site question: According to the sign board at the GZ the Termitatrium is built from what two components? and What what would you estimate the height if the mound to be?
4) Describe any other intersting things you saw on your journey to the GZ - feel free to post picture of any other termite mounds you may see on your journey around the park
Please submit all answers via email to the CO. Answers not received within 2 weeks of logging will result in your log being deleted.