Besides small game and the Wonderboom itself, the Wonderboom
Nature Reserve also protects several historical sites, some recent,
some ancient.
On your way from the listed trailhead S25 41.254 E28 11.491, you
will walk on a paved trail with lots of this ripple quartzite
rocks. The listed waypoint will take you to a massive rock face
with evidence of ripple marks left on the quartzite rocks by an
ancient shallow sea, look at the ripple marks to the east and to
the top of this rock face. Today this area is 1260m above sea
level. More evidence of a shallow sea can be found at cache site
GC15W4T.
Creation of the Magaliesberg Mountain
Range:
The Magaliesberg Range has a very long geological history. Its
quartzite’s, shale’s, 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. We can call this the first stage of the
process entailed the deposition of the Transvaal Series of
sedimentary rock on the floor of a shallow sea. The ripple marks
found in the quartzite rocks from the Pretoria Group are testimony
of the ancient sandy beaches around this prehistoric sea.
About 2 billion years ago pressure built up in the earth’s
mantle and thrust molten magma from the north in-between the layers
of sedimentary rock. During this process the rocks of the Transvaal
Series started subsiding into the molten magma.
A 65 000 square kilometer reservoir of molten rock seethed
(boiled) beneath the site of the ancient sea and solidified into
the largest known intrusion of its kind in the world. The Bushveld
Complex refers to the variety of igneous rocks and the associated
mineral wealth that resulted from this upheaval.
With the passage of time a complex system of weathering (eroded)
over millions of years that eventually resulted in the formation of
the mountains we know today. The range now forms a natural barrier
between the lower lying Bushveld to the north and the cooler
Highveld to the south
Historical the area around the Magaliesberg range has probably
seen the longest occupation by humans of any place on earth. The
reason for this claim is the discovery of the remains of the
earliest hominin species in and around the Sterkfontein Caves,
(earth cache GCQJM6). In 1955 pre-historic tools were found on the
slopes of the Magaliesberg, see Cache GC13N24, and on top of the
mountain in this Wonderboom Nature reserve evidence of the Iron Age
occupation was discovered.
(Acknowledgments: Wonderboom Nature Reserve; “Anderkant die
Magallies” by Loreen Nel & Wikipedia).
In order to qualify to log this cache, you need to answer the
following questions and s=email the cache owner. Any logs not
accompanied by an email will be deleted.
- Take a photo of your GPSr at this spot with the Ripple marks
visible in the quartzite rocks and include in your log.
- From which towns do the Magalliesberg Mountain Range extends
East and West?
- Why do you think in the early Stone Age, rocks in this area
were used for the purpose of hunting and butchering tools?
- What was the Mountain called before its current name the
“Magalliesberg” Mountain? (before the Voortrekkers were entering
the area)
- Describe the quartzite rocks in the area. (i.e. surface
texture, grain and colours)