Dinosaurs are back!!!
No they’re not. Well, at least they were once here . . . in Zimbabwe (ok, well long before it was Zimbabwe).
So we got to find out during our recent visit to Sentinel Ranch within the Greater Mapungubwe Transfrontier Conservation Area. Not many people would stand up and seriously publicly state that they believe that this planet was once upon a time inhabited by these typically gigantic terrestrial reptiles, commonly known as dinosaurs.
Prior to my Sentinel visit, I certainly wouldn’t have. But my perceptions have since broadened and I can bravely say dinosaurs did exist at some point in the history of this earth.
Vanessa Bristow, one of the owners of Sentinel Limpopo Safaris, took us for a tour of the area’s ‘“Triassic Park”. I call it so because most of the fossil finds here are of late-Triassic dinosaurs species.
The Triassic period dates back some 230 million years ago.
Fascinating late-Triassic dinosaur fossil finds have been discovered within Sentinel Ranch, including 240 million-year-old Erythrosuchus teeth (the Erythrosuchus is believed to be an early ancestor of the crocodile) and many 210-million-year-old Massospondylus fossils.
How the name Sentinel came about
Did I mention where Sentinel Ranch got its name? It actually comes from a huge boulder (in a balancing rock formation) on the top of a cliff range near the entrance to the Greater Mapungubwe Transfrontier Conservation Area.
It is called the “Sentinel Head” and seems to have total supervision of the area.
From some angles it almost looks like the head of a dinosaur (or am I stretching it a tad far?).
The highlight of our visit is the site where an almost intact Massospondylus pro-sauropod is partially exposed in its sandstone sarcophagus on a hillside.
“This dinosaur must have stood about six metres tall, with a long tail and was most likely bipedal . . . ” describes Vanessa.
Some of the stuff she explains fails to penetrate the mental block that I experience as I begin a review of my old perceptions on this issue. I had always thought that this dinosaur doohickey was the stuff of movies (remember Jurassic Park?) and some outlandish television documentaries.
“ . . . that claw. It may have been carnivorous, but most likely omnivorous!”
The upper body and head of the Massospondylus is not visible: it may still be swallowed up by the rock, or eroded away.
Vanessa continues to explain something about the dinosaur’s long vertebrae, leg bones and forefeet.
I’m particularly impressed by the tail. Something you would imagine a dinosaur to be like.
Scattered around this site are bits of dinosaur bone (or is it “rock”?).
Our guide explains to us that overtime (say 210 million years or so), the dinosaur bones fossilised as bone matter was gradually replaced by rock matter. The fossils are rock hard and weigh a ton — so to speak — but you can still easily see the structural elements of the original bone.
I pick up an animal bone close to the site of the fossil find and notice the level of deterioration. There is no chance this bone is getting fossilised.
I then think something must have happened back then, some 200 million years ago or so, an earthquake perhaps?
Or maybe a volcanic explosion that might have caused the extinction of the dinosaur species and got them frozen in time.
But then again scientists say volcanic eruptions only happened 80-70 million years ago and that later, better known species of dinosaurs are thought to have become extinct 65 million years ago with a massive meteorite that struck the earth.
I guess we will never know.
The sand and mudstones of Sentinel were laid down by geographical forces over 200 million years ago, that is, prior to the advent of Continental Drift, hence you’ll find that the Massospondylus has been discovered on other continents as well.
Oh, and the red Triassic soil. According to Vanessa, wherever you come across such soil there is a chance of finding dinosaur fossils.
And the sandstone . . . oh come on!
The Massospondylus seems to have been a common resident in this area as at least 20 other sites have been found.
A word to the wise palaeontologist: Few of these 20 other sites have been excavated as yet!
Palaeontologist or not, Sentinel’s dinosaur fossil sites are the place to visit because they are among Zimbabwe’s richest palaeontological grounds.