In April of 2023, I had the chance to visit the Pilanesberg National Park in South Africa. The Pilanesberg National Park is located north of Rustenburg in the Northwest Province, (210 km northwest of Johannesburg), South Africa.

The Pilanesberg National Park interested me to explore, because this massif appears to be almost circular in outline, (pictured below). It measures about 28 km east to west and 24 km from north to south, and covers about 530km².

Pictured above, over millions of years nature has sculpted it into a series of ring-like mountains that provide a natural sanctuary of diverse habitats, which are home to a wide range of animal life.

Pilanesburg massif stands high above the rather featureless Bushveld plain, starting about 40km north of Rustenburg. We entered the park on the southern gate called the Bakubung, (approached on highway R565).

Pictured above, The “Pilanesberg Complex” was intruded through the much older rocks of the Western Limb of the Bushveld Complex around 1.2 billion years ago.

Pictured above, the conventional explanation is that the Pilanesberg Complex is largely volcanic, formed by a series of eruptions around 1.2 billion years ago that produced lava flows. agglomerates and tuff beds that ultimately collapsed inwards.

{The images above were taken from “Pilanesberg Guide: Jacana Publishers 2004”}

At depth, and following a number of large-scale, ring-like fractures, pulses of alkaline magma forced their way upwards to form several thick, funnel-shaped “Foyaite” intrusions and plugs of syenite and alkali granite. At some early stage, caldera-like subsidence of the volcano took place along conceptual ring faults, followed by radial fracturing that formed a pattern of sub-parallel dikes, which occur mostly to the northwest and southeast of the complex, (imaged above).

Pictured above, as volcanic activity waned, the remaining magma cooled in the cracks as bands of volcanic rock (mainly syenites and Foyaites). Geologists call these structures dikes. The rate of cooling and the composition of the magma affected the type of rock that formed in each dike. For instance, white Foyaite has particularly coarse grains and is formed when lava cools slowly. Red syenite forms when magma contains plenty of water.

{White, Red and Green Foyaite found at interpretive sites near the indicative ridges and red syenite found near an outcropping near the Bakgatla Gate}.

Pictured above, the ring-like hills are the result of at least five funnel-shaped intrusions, stacked one on top of another, and made of varieties of a rare igneous rock called ‘Foyaite’. Foyaite is a type of coarse-grained syenite containing alkaline feldspars, nepheline (a rare sodium aluminum silicate) and sodium-rich pyroxenes and amphiboles, and no free quartz. The Foyaites differ in their mineral proportions and color but have similar chemical compositions. They are called alkaline as they are composed largely of potassium and sodium-rich silicate minerals and are relatively poor is silica.

Outcrops of white and green Foyaite and of red syenite make up the ridges in the southwestern part of the park. These rock types are especially resistant to erosion and weathering, so they were left behind as hills and ridges while streams and glaciers scrapped and scoured away weaker types of rock.

Pictured above, the Pilanesberg is one of only 3 alkaline volcanoes in the world and is exceptionally old. At it’s zenith, the volcano towered to 7000m in height, rivalling Africa’s high peak, Mount Kilimanjaro, in grandeur. The end result is several concentric “onion rings” of rocks and ridges of different ages. However, the erosion over millions of years has stripped away the mountain top. What we see today then is not so much a volcanic crater, but a cross section through the magma pipes that were located at great depth below the mountain’s summit.

Over millions of years the Pilanesberg volcano has weathered to approximately 10% of its former height. The concentric rings of hills have created a variety of habitats. South-facing hill slopes receive less sunlight than north-facing slopes and support different tree species. Where outpourings of magma have been weathered into rocky outcrops of red Syenite, separate plant communities occur. Pediment and valley grasslands and savannas occur in the center of the Park, and Acacia thicket are found on deeper soils.

Pictured above, the north-facing hill savanna slope receive more sunlight and are therefore drier than the south-facing slopes. The dominant tree is the red bushwillow, and other trees include the hook thorn, large-fruited bushwillow, live-long and wild pear.

Pictured above, the south-facing hill savanna is characterized by hook thorn beech, wild pear and buffalo thorn. The absences of elephants from the system for over 140 years prior to now, allowed the mountain cabbage tree to spread throughout the Pilanesberg. These trees and aloes are sought after by elephants, but they have been recently re-introduced into Pilanesberg, (as seen above).

Pictured above, the pediments contain a subterranean layer of ferricrete (ouklip), an accumulation of hard sheets of iron oxides. This prevents tree growth and maintains open grasslands. Where ferricrete has been broken by run-off or river erosion, the beach-wood is able to invade the grasslands from the hills, while the sweet thorn invades up-slope from the valleys.

Pictured above, the valley savanna is dominated by sweet thorn, umbrella thorn, karree, lead-wood, tamboti and buffalo-thorn trees. In the northwest corner of the Park, a savanna dominated by umbrella thorn occurs on the plain, west of the hills.

Thickets of sweet thorn and black thorn occur on brack soils in the valleys.

Pictured above, outcrops of red syenite have weathered into a jumble of re-brown boulders that support a thicket dominated by lavender fever-berry, large-leaved rock fig, and the near-endemic red balloon tree.

Pictured above, Pilesberg is situated in a transition zone between the wetter savannas of the eastern half of South Africa and the arid savannas of the Kalahari. Arid savanna species such as the Tsessebe, (pictured below), and Springbok, (pictured above). The Springbok is the only gazelle species found in South Africa.

Pictured above, reputedly the fastest of the African antelope, Tsessebe favor the open savanna of the pediments. They are rare in South Africa and have declined throughout their historic range.

Pictured above, the reserve’s most prolific antelope, impala are the preferred prey of wild dog, leopard and cheetah.

Pictured above, one of the most common herbivores in the Reserve, herds of plain zebra are often encountered on the grasslands surrounding Mankwe Dam Lake.

Pictured above, these mammals are often seen in the company of plains zebra. Blue wildebeest prefer short grass conditions and are often encountered on the short grasslands surrounding Mankwe Dam Lake.

Pictured above, weighing up to seven tons, elephants were frequently encountered throughout the Reserve. During the heat of the day they gathered near waterholes, and were often found feeding along the banks of Mankwe River.

The Pilanesberg Park supports more than 50 species of large mammals and is home to 15 species of antelope, which compare very favorably with 18 species for the entire Kruger National Park.

Pictured above, Hippos are seldom seen on land except at night when they emerge to graze. This seemed odd…..Their loud grunts add to the tranquil ambience of all the deeper impoundments of the Reserve.

Pictured above, the dark ear patches behind the eyes and the royal blue on the belly and flanks, distinguishes it from the Cape Glassy Starling. On the upper wings are two rows of dark spots. It was found in single in one of Pilanesberg’s savannahs. It should be mentioned that at least 10 pairs of closely related birds are present in Pilanesberg, each species typical of either wet or dry savannas.

Pictured above, the African Sacred Ibis (Threskiornis aethiopicus) was found on the Lengau Dam near the Bakubung Gate.  It has a predominantly white plumage with a bare, black head, long downcurved bill and black legs. It is usually found in Egypt and closely resembles the Australian White Ibis. It was strange that I found them here.

Pictured above, a common primate of the Pilanesberg’s hills and valleys, Chacma Baboons form troops guarded by large adult males. They are largely plant eaters but also feed on scorpions, insects, lizards and bird’s eggs.

Pictured above, the White Rhinoceros Ceratotherium simum is the second largest mammal found in the Pilanesberg and is common in the valley grasslands. Pilanesberg safeguards one of the largest populations of this potentially threatened species in the world.

Pictured above, White Rhinos are grey, almost hairless with two horns, (these horns have been cut off to protect them for poachers), The long head with square-shaped mount is well adapted for grazing. Head is normally held low. They seem to prefer open savannah with thickets of cover. I here that the males are very territorial.

Pictured above, A sole Black Rhinoceros Diceros bicornis found in the valley thickets of Twin Dams area. It had a pointed upper lip and short head, which is normally held high. It is smaller and more aggressive than the White Rhino. Usually solitary. It has poor eyesight, but has a keen sense of hearing and smell. Browses the thicket by using its upper lip like a elephant’s trunk. Here it favored the dense Acacia thickets.