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Croeser Synoptic Table Geological History Last 500M Years

Croeser Synoptic Table Geological History Last 500M Years

A synoptic table of the geological and life history of the past 500 million , with particular focus on southern and KwaZulu-Natal. Compiled by Peter Croeser, Natal Museum, Pietermaritzburg,1998.

P E Millions E EPOCH ROCK CLIMATE AND EARTH HISTORY DOMINANT AND PLANTS R of years R GROUPS A ago I O D Present The Holocene is dominated by the last Ice Age which Modern man, Homo sapiens sapiens, finally emerges some 200 covers much of northern Europe, Asia and North 000 years ago in either southern or eastern Africa. Some 110 000 America with and permanent snow starting years ago, during the onset of the last Ice Age, modern man

HOLOCENE about 110 000 years ago and ending abruptly 11 500 begins leaving Africa into Europe and the Middle East across land C years ago (within the space of about 70 years). bridges formed by low levels. The abrupt ending of the Ice Age and the onset of warmer, wetter conditions than the present sees E Q During the Ice Age sea levels are about 6 metres below the emergence and development of pastoralism, agriculture, and present levels. urbanisation by modern humans. U N 0.11 A Maputaland Group In , coastal sand dunes became consolidated to During the mid Pleistocene the climate in Natal was warm to dry, • Berea Red Sand (red form the cliffs of the Durban Bluff, while red but lower-lying areas supported a rich fauna. Larger animals O T decalcified sands) sand dunes further inland formed the ridges on which included now extinct of buffalo, elephant, rhinoceros and the Durban Berea is built during the middle to late hippopotamus whose fossilized bones together with , Z PLEISTOCENE • Durban Bluff Pleistocene (700 000 to 100 000 years ago) are found at Port Durnford. E Sandstone O During the Pleistocene sea levels rose to their present During the early Pleistocene, Australopithecus died out (about one

R level and have remained there for the past 4 million million years ago) and Homo erectus, similar in size to modern

years, with only small variations of about 6 metres man, became the dominant early man species, spreading from N either way. Africa into Europe and Asia.

I 1.8 At the end of the Pliocene, parts of Natal were raised by Towards the end of the Pliocene Australopithecus, crouched and A upto 180 metres above sea level (either by dropping only 1,4 metres tall, co-existed with stone-tool-making man (Homo C or by movement in the earth's crust). The seas habilis and erect-walking Homo erectus). R over Zululand drained off the land, turning the earlier Pliocene into the coastal lowland plains we During the Pliocene, ancestors of the mammals we know know today. The sea retreated to some 60 metres Y today were abundant and Africa became the birthplace of PLIOCENE below the present sea level. The dunes formed at the man. edge of the sea during this stage are now a line of reefs a kilometre or so off the of Zululand from Black The oldest fossilized remains of early, small-brained man Rock to Mtunzini. (Australopithecus) date back some three million years ago and were found in eastern and . During the early to mid Pliocene the sea levels steadily rose to some 50 metres above present levels, once again isolating Table Mountain from the mainland and Corals, sharks and tropical shells and fish were abundant in the covering the low-lying coastal plains of Zululand for the shallow, warm sea that once more covered low-lying areas of last time. Zululand.

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P E Millions E EPOCH ROCK STRATIGRAPHY CLIMATE AND EARTH HISTORY DOMINANT ANIMALS AND PLANTS R of years R GROUPS A ago I O D 5 At the end of the Miocene (between five and six million At the end of the Miocene, when the Mediterranean basin dried up, MIOCENE years ago) sea levels dropped sharply, the climate many ancient Asian mammals entered Africa for the first time became increasingly dry, deserts grew and the including the elephant family, many antelope, hyaenas and sabre- Mediterranean basin dried up. toothed cats.

During the mid Miocene the climate was warm and wet as Africa moved northwards over the Equator and tropical forests covered the middle of Africa. A During the Tertiary, mammals, no longer suppressed by , C T longitudinal bulge developed down east Africa and then diversify and flourish and become dominant on land. Flowering collapsed to form the Valley. Interrupted rivers plants spread rapidly and grasslands develop. E E drained internally to form the great of central and east Africa. N R The early to mid-Miocene shallow, warm seas covering lower-lying During the early Miocene, sea levels rise once again to Zululand support more than 100 species of shellfish and giant O T isolate Table Mountain from the and sharks (like Carcharodon megalodon). The fossilized remains of warm, shallow seas cover the low-lying Zululand plains these extinct animals, including nearly 12 cm long sharks' teeth Z I from Port Durnford to the wide Maputaland plains of and species of Pecten (shells resembling the Shell Petrol logo), are Zululand and Mocambique. found from Richards Bay to Uloa on the Mfolozi River. O 23 A OLIGOCENE

I 38 R EOCENE

C 54 Y PALAEOCENE

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P E Millions E EPOCH ROCK STRATIGRAPHY CLIMATE AND EARTH HISTORY DOMINANT ANIMALS AND PLANTS R of years R GROUPS A ago I O D 65 Uitenhage At the end of the sea levels drop rapidly to The fifth and last mass extinction of plant and life was at Group well below present levels, exposing land bridges linking the Cretaceous-Tertiary (K-T) boundary at the end of the C North America with Europe and Asia, southern Asia with Cretaceous period. Inhabitants of the shallow, warm seas that Zululand Australasia and Africa with Europe. covered continental lowlands around the world for much of this M R Group period, died out as sea levels dropped to the cold deep-sea *St Lucia continental margins well below present sea levels. On land E E migrations of animals and plants along the newly exposed land bridges between the continents led to the introduction of new S T diseases while ecological systems disturbed by the new invaders For much of the Cretaceous period the world climate is collapsed or changed, leading to the extinction of many plants and O A warm and sea levels much higher than at present, animals dependent on them. The final blow may have been struck creating shallow warm seas over most continental by a giant meteorite colliding with the Earth. A thin dust layer of a Z C lowlands. The lower-lying Zululand plains and southern metal, Iridium, commonly found in space asteroids and meteorites Mocambique are covered by sea which also isolates the but rare on Earth, has been found in various parts of the world in O E Table from the Western Cape mainland rocks formed at the end of the Cretaceous period. Among groups and covers much of the coastal plain. In that did not survive were the giant spiral-shelled ammonoid cuttle- I O North America shallow seas cover the eastern and fish and the dinosaurs, except for birds. central lowlands from the foot of the Rocky Mountains C U to the Appalachians. The Cretaceous was a period rich in animal and plant diversity. The first snakes developed from burrowing and birds such as S waders, cormorants and owls evolved and shared the skies with the pterosaurs. In North America dinosaurs flourished around the rich, shallow inland sea and included the well-known plant-eaters Triceratops and the duck-billed hadrosaurids (eg. Parasaurolophus and Corythosaurus) and meat-eaters such as Tyrannosaurus and Stenonychosaurus. 142 Karoo weather was warm and wet and while animals In the late Jurassic the giant sauropod plant-eating dinosaurs J sequence and plants flourished in most parts of the world, major appeared: Apatosaurus (21 m long) in North America, Cetiosaurus M changes were taking place in Gondwanaland. (18 m long) in north Africa, Brachiosaurus (25 m long, 16 m high, U 50 tons) in east Africa as did large predators like Megalosaurus (9 E • Gondwanaland began tearing apart and the m long) in South America, Asia and probably Africa. Small 183 R Basalt volcanic activity that ensued saw the Stormberg theropod dinosaurs gave rise to the first birds, plants flourished and S Group lavas (forming the Drakensberg basalts) flood the there were thick forests. A (= Upper Stormberg) Karoo Basin destroying all of its terrestrial life O • Drakensberg Basalt between 165 and 183 million years ago. The Living in southern Africa during the was one of the S Formation Lavas weakening and flexing of the African continental smallest true dinosaurs, (1 m long), from Lesotho, a Z plate in southern Africa leads to magmatic dolerite plant-eater about the size of a small Alsation dog, which ran on its S intrusions in the form of vertical dykes and long, slender hind legs. Larger two-legged southern African O horizontal sills (such as the flat dolerite platform on predators included Syntarsus (3 m long) from . Small I which Howick rests, cut by the Umgeni plunging rodent-like mammals, flying pterosaurs, crocodiles, and I down the Howick Falls). amphibians were amongst the other land animals. Plants included C • present coastline forms very tall with true cones, cycads, tree and horsetails. C • interior uplifted • river systems develop

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E Millions P EPOCH ROCK STRATIGRAPHY CLIMATE AND EARTH HISTORY DOMINANT ANIMALS AND PLANTS R of years E GROUPS A ago R I O D 206 Karoo Drakensberg Basalt At the end of the some 75 % of marine and sequence Group (=Lower some land dwellers die out in the fourth major mass extinction. Stormberg) During this hot, dry period there were lush coastal and riverine forests of tree ferns and, in drier areas, thinner forests of conifers (cone-bearing trees), similar to monkey-puzzle trees, and cycads. Descendants of these trees can be seen in the Botanical Gardens in Pietermaritzburg. Dinosaurs flourished and begin to dominate the land. Other animals whose remains date from this period include the first lizards, primitive crocodiles, first mammals and a M T • Cave form under semi-desert conditions as variety of little different to those found today. sandstones (yellow wind-blown sand covers most of the Karoo Basin Cave Sandstone semi-desert dwellers include the last of the Karoo E R cliffs of OFS) Basin primitive armoured crocodiles, Notochampsa. The Red Beds represent increasingly hot and drier S I conditions, but supported a rich animal life. In the fossil remains of the earliest Karoo true • mammals are found in the Red Beds: the tiny and mustones/ O A -eating Megazostrodon (13 cm). Remains of the first lizards (red beds) and the primitive, very small fresh-water crocodiles

Z S Erythrochampsa and Orthosuchus (70 cm) are also found in the

Red Beds. Living with them in the late Triassic in southern Africa O S were early true dinosaurs: the earliest bird-hipped dinosaurs,

Fabrosaurus and (1 m long), and the - I I hipped plant-eating prosauropod ancestors of the giant

Brachiosaurus dinosaurs of East Africa: the partly bipedal C C (6 m long) and the four-legged (6 The Molteno climate was wet with periodic flooding. m long) and (12 m long). Melanorosaurus was one of the largest dinosaurs to live in the Karoo Basin. • Insect remains found with fossilised Molteno strata plants include shales/sandstones The upper Beaufort in Natal is divided in two different mayflies, dragonflies, cockroaches, beetles, grasshoppers, bugs

types (or zones) of rock strata reflecting the quite and butterflies. Upper ‘’ different climates which prevailed when they were and sandstone formed. The two zones are named after the animals, Although the Gorgonopsia, Therocephalia and Dinocephalia did zones: both dicynodonts, whose fossilized remains are most not survive the extinctions, some dicynodonts did survive commonly found the respective strata: into the Upper Beaufort of the early Triassic. Living with them were 1) The zone represents a warmer, drier cynodonts (ancestors of the mammals), archosaurs (ancestors of Tarkastad Subgroup environment in which is no longer found. the true reptiles, including crocodiles, and of the dinosaurs) and amphibians. The following animals were found in the two upper • Cynognathus zone 2) The Lystrosaurus zone with its characteristic purple Beaufort zones: or red shales resulting from the prevailing wet climate, Cynognathus zone (warmer, drier climate): include the interrupted by bands of sandstone laid down during dicynodonts Kannemeyria, Diademodon and Trirachodon (plant- • Lystrosaurus zone periodic flooding. eaters), the powerful flesh-eating Cynognathus and the primitive archosaur . Lystrosaurus zone (wetter climate with periodic flooding): fossils include the puddle and pool-loving dicynodont Lystrosaurus, the archosaur Chasmatosaurus and the cynodont .

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P E Millions E EPOCH ROCK STRATIGRAPHY CLIMATE AND EARTH HISTORY DOMINANT ANIMALS AND PLANTS R of years R GROUPS A ago I O D P 248 Permian Karoo Lower ‘Beaufort Group’ The lower Beaufort was a wet period with marshes, At the end of the Permian nearly all plant and animal life on earth P sequence shale and sandstone pools and lakes covering much of the Karoo Basin and in the sea died out in the greatest mass extinction of life in the A zones: including western Natal. Most of the southern Transvaal earth's history. Fish are severely reduced, ammonoids are nearly E and Natal coalfields were formed from the abundant extinguished, corals only just survive, crinoids are nearly wiped out L vegetation that flourished in the marshes and and trilobites, having survived two earlier extinctions, finally R of this period. become extinct. Before the extinction forests, now A preserved in the coalfields of Natal, covered stretches of the Natal M Adelaide subgroup of midlands and northern Natal. In the marshy lowlands the early E Karoo Sequence mammal-like reptiles flourished during the lower Beaufort: I Daptocephalus zone: O The dicynodont Daptocephalus dominates this layer towards the A • Dicynodon zone end of the Permian in Natal. Z • Cistecephalus zone Cistecephalus zone: N • Tropidostoma zone • Gorgonopsia (died out end Permian) included the flesh-eating O • Pristerognathus zone Rubidgea (2 m long). • • Tapinocephalus Dinocephalia, the earliest and most primitive of the mammal- I zone like reptiles, finally died out during the mid Permian. • Dicynodontia were abundant during this period (most died out • Endocynodon zone C end Permian, some survived to mid Triassic). They included

Endothiodon, Cistecephalus, Daptocephalus, Emydops and

Lystrosaurus (70 cm) found in Africa, Antarctica, Russia, India

and China which all formed part of Gondwanaland.

• Therocephalia (most died out end Permian but give rise to the

Cynodontia, the ancestors of the mammals).

Tapinocephalus zone:

The lowest animal fossil-bearing zone of the Karoo Basin, named

after a giant dinocephalian.

255 The thin seams from the upper Ecca include leaf impressions The Ecca climate was wet (with slow moving rivers of Glossopteris trees which later formed much of the coal mined in shales and carrying fine mud and clay particles into the Karoo Natal. The first scorpions appear on land at the beginning of this sandstones Basin resulting in fine-grained layers of shales) with period (280 mya). periodic flooding (when large amounts of sand and • Volksrust Formation were swept into the Karoo Basin giving rise to bands shales of coarser-grained sandstones). The shales and • Vryheid Formation sandstones are interlaced with thin plant-derived coal sandstones & shales seams (seen at the Sweetwaters quarry) lubricated by • Pietermaritzburg aquifers which cause periodic landslips (Queen Formation shales Elizabeth Park resulted from a major landslip while minor landslips periodically affect the Town Hill section of the N3 freeway). The mid-Ecca iron rich shales give * Dwyka Formation tillites Pietermaritzburg bricks their characteristic red colour (eg the bricks of the City Hall). The lower lying areas of Pietermaritzburg are built on quick-draining exposed Ecca shales.

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P E Millions E EPOCH ROCK STRATIGRAPHY CLIMATE AND EARTH HISTORY DOMINANT ANIMALS AND PLANTS R of R GROUPS A years I ago O D 290 C Karoo The Dwyka was a very cold period. The old Fish, crinoids and corals recover from the extinction and A sequence Dwyka tillites Gondwanaland moved over the South once more begin to flourish R Pole and glaciers covered much of what is now Natal. B Glaciers moved down into Natal from the mountains of O the present-day Antarctic. Sheets of rock scraped by N the glaciers can be seen in the grounds of the I University of Durban-Westville and just east of F Piertermaritzburg near Northdale. Glacial mud and rock E () ground by the glaciers became petrified to form R tillite. Tillite is a hard greenish blue to nearly black rock O containing broken, angular fragments of stones crushed U by the glaciers. Exposed tillite can be seen at Ashburton Upper S and Mpushini and at road gravel quarries near Durban where it is a favourite rock for concrete aggregate and tar roads. 354 D Cape At the end of the Devonian another mass extinction sees some 70 E Super- Lower Witteberg percent of invertebrates and most fish dying out. During the V group quartzites Devonian the first spiders, pseudoscorpions and mites appear on O land (395 million years ago). N Bokkeveld shales I A N 417 S Upper Table Mountain Most animal groups recover from the extinction at the end of the I sandstones and life begins to flourish in the seas. Fish, crinoids and L corals radiate become abundant and trilobites, severely reduced, U manage to continue. R I A N 443 O Lower Table Mountain The Gondwanaland supercontinent (including the future Towards the end of this period cold, glacial conditions lead to the R sandstones South America, Africa, Antarctica, Australia, first major extinction of life in which marine invertebrates, including D Madagascar and India) drifts over the South Pole and trilobites, are decimated but early fish survive. O glaciation sets in at the end of this period. V I C In this period the first fishes, trilobites, crinoids, corals and I ammonoids appear in the seas. A N 495 Nama Fish River sub group Group 545 4 550 dinotabl.doc july 1998 A Natal Museum Education Department guide compiled by Peter Croeser, July 1998

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