Sibebe Rock
The coordinates lead you near the top of Eswatini's (Swaziland's) and also southern-Africa's most breathtaking geological features. Rising 350m above the valley of the Mbuluzi River and 1488m above sea level, the Sibebe Rock is the largest exposed granite pluton and the possibly the second largest monolithic rock. Only the Ben Amera (Mauritania) and Zuma Rock (Nigeria) can fight the Sibebe for the top stop of being the largest monolith in Africa. However based on the area covered, 16.500ha of the granite dome you are standing on easily beats any other African monolith. This impressive slab of volcanic rock is a staggering three billion years old and is one of the most important geological sites in Africa.
Geological significance of Sibebe
Monolith formation:
Monoliths are basically geological features consisting of a single massive stone or rock. Volcanic or other processes may give rise to a body of rock resistant to erosion, inside a body of softer rock such as limestone, which is more susceptible to erosion. When the less resistant rock is eroded away to form a plain, the more resistant rock is left behind as an isolated mountain. The presence of a monolith typically indicates the existence of a nearby plateau or highland, or their remnants. This is especially the case for monoliths composed of sedimentary rock, which will display the same stratigraphic units as this nearby plateau. Monoliths are as well known as inselbergs (island-mountains) or monadnocks.
Granite:
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite has a medium to coarse texture, occasionally with some individual crystals larger than the groundmass forming a rock known as porphyry. Granites can be pink to dark gray or even black, depending on their chemistry and mineralogy. Outcrops of granite tend to form tors, and rounded massifs. Granites sometimes occur in circular depressions surrounded by a range of hills, formed by the metamorphic aureole or hornfels.
Granite is an igneous rock that formed (and still forms) below the surface of the earth by crystallisation of a molten rock known as magma. When molten, granite magma has a temperature well above 1000 degrees centigrade - which is nearly white hot! -- and by the time it has cooled to about 600 degrees centigrade, and still glowing a dull red, it is already almost solid. The entire process of intrusion of the granite magma, including the cooling process, takes place underground. Hot springs and boiling mud pools and geysers may develop at the surface of the earth over the cooling granite magma.
Sibebe survivor walk
Sibebe survivor is an annual walk in Mbuluzi, Eswatini, which involves a climb to the top of Sibebe Rock. Initiated by the Rotary Club of Mbabane-Mbuluzi in July 2004, the Sibebe Survivor hike follows a course from Mbuluzi High School to the top of the rock and back. People from all around the world are motivated to join in the annual climb of Sibebe Rock, which is always scheduled for the last Sunday in July. If you have the chance, I truly recommend taking part in it, as not only you will have the chance to participate in a beautiful walk, but you will also contribute to the community of Eswatini.
How to get there
It is hard to appreciate the scale of Sibebe from below. That’s partly because there is no single spot from which the whole rock is visible; and partly, also, because large areas of it are vegetated, with patches of grassy hillside and forested clefts. The best way to see it is, of course, to climb it. There are many routes up and over, some starting from private properties on its lower slopes. Unless you are in the company of locals, however, you are best off following the official route via Sibebe Hiking Trails (www.swazitrails.co.sz), a community project that manages the rock. From here, you can follow a well-marked and manageable path to the top – either alone or with a guide. The going is steep in places, but it’s a hike, not a climb, and will take you about an hour to get up.
On top, you will find a wonderland of huge sculpted boulders and gleaming slopes of exfoliating granite. Trails radiate in all directions, leading to caves, waterfalls and hidden pockets of indigenous forest. The flora is impressive, with orchids and other wild flowers carpeting the grasslands from October to December. The place is also an amazing opportunity for bird-watchers to spend their day at.
Your task:
Hopefully, you have made it to the top of the spectacular Sibebe Rock and you were able to fully appreciate this geological wonder. In order to log this Earthcache, please send the answers to the following questions to me via the message center:
- Briefly describe in your own words how a monolith is formed.
- While being at the top of the Rock, look around you. Is Sibebe the only monolithic granite dome in the area, or are there any others visible on the horizon?
- Is the surface of the monolith smooth or rugged? Why do you think that is?
- Describe the color and the grain pattern of the granite that the rock is made out of.
- (optional) Include a picture of yourself / your GPS with the Sibebe Rock in the background :)
note: Climbing the steep slopes of Sibebe can be dangerous, therefore please hold back from doing so especially after the rain, which makes the slopes even more slippery. Try to remain on the trails the whole time. Also make sure you take plenty of water and suncream: it gets hot on the exposed slopes. Most importantly, have fun!
