African evidence support Younger Dryas Impact Hypothesis

By: Thomas Schmitt Attorney on October 02, 2019 / comment : 0 Earth Science, Geology, Palaeoclimate, Palaeontology, South Africa

A team of scientists from South Africa has discovered evidence partially supporting a hypothesis that Earth was struck by a meteorite or asteroid 12 800 years ago, leading to global consequences including climate change, and contributing to the extinction of many species of large animals at the time of an episode called the Younger Dryas.

A world map that shows where similary platinum spikes have been discovered in the world. The latest discovery is at the Wonderkrater site in Limpopo Province, South Africa [Credit: Francis Thackeray/Wits University]

The team, led by Professor Francis Thackeray of the Evolutionary Studies Institute at the University of the Witwatersrand in Johannesburg, South Africa, discovered evidence of a remarkable "platinum spike" at a site called Wonderkrater in the Limpopo Province, north of Pretoria in South Africa. Working with researcher Philip Pieterse from the University of Johannesburg and Professor Louis Scott of the University of the Free State, Thackeray discovered this evidence from a core drilled in a peat deposit, notably in a sample about 12 800 years old. This research was published in Palaeontologia Africana.

Noting that meteorites are rich in platinum, Thackeray said "Our finding at least partially supports the highly controversial Younger Dryas Impact Hypothesis (YDIH). We seriously need to explore the view that an asteroid impact somewhere on earth may have caused climate change on a global scale, and contributed to some extent to the process of extinctions of large animals at the end of the Pleistocene, after the last ice age."

Many mammals became extinct in North America, South America and Europe at the time of the Younger Dryas. In South Africa a few extraordinary large animal species became extinct, not necessarily at exactly 12 800 years ago, but close to that period. These megafauna include a giant African buffalo, a large zebra, and a very big wildebeest.

Human populations may also have been indirectly affected at the time in question. In North America there is a dramatic termination of the stone tool technology of Clovis people. Remarkably, archaeologists in South Africa have detected an almost simultaneous termination of the Robberg stone artefact industry associated with people in some parts of the country, including the area around Boomplaas near the Cango Caves in the southern Cape, close to the town of Oudshoorn.

"Without necessarily arguing for a single causal factor on a global scale, we cautiously hint at the possibility that these technological changes, in North America and on the African subcontinent at about the same time, might have been associated indirectly with an asteroid impact with major global consequences," says Thackeray. "We cannot be certain, but a cosmic impact could have affected humans as a result of local changes in environment and the availability of food resources, associated with sudden climate change."

At Wonderkrater, the team has evidence from pollen to show that about 12 800 years ago there was temporary cooling, associated with the "Younger Dryas" drop in temperature that is well documented in the northern hemisphere, and now also in South Africa. According to some scientists, this cooling in widespread areas could at least potentially have been associated with the global dispersal of platinum-rich atmospheric dust.

A large crater 31 kilometres in diameter has been discovered in northern Greenland beneath the Hiawatha Glacier. "There is some evidence to support the view that it might possibly have been the very place where a large meteorite struck the planet earth 12 800 years ago," says Thackeray. "If this was indeed the case, there must have been global consequences."

Thackeray's team believes their discovery of a platinum spike at about 12 800 years ago at Wonderkrater is just part of the strengthening view that an asteroid or cometary impact might have occurred at that time.

This is the first evidence in Africa for a platinum spike preceding climate change. Younger Dryas spikes in platinum have also been found in Greenland, Eurasia, North America, Mexico and recently also at Pilauco in Chile. Wonderkrater is the 30th site in the world for such evidence.

"Our evidence is entirely consistent with the Younger Dryas Impact Hypothesis" says Thackeray.

The discovery in South Africa is expected to be integrated with those made in other parts of the world, recognising that the source of the platinum at Wonderkrater could hypothetically be cosmic dust that was dispersed in the atmosphere after a meteorite impact in Greenland.

The probability of a large asteroid striking Earth in the future may seem to be low, but there are thousands of large rocks distributed primarily between Jupiter and Mars. One in particular, classified as Apophis 99942, is referred to as a "Potentially Hazardous Asteroid". It is 340 meters wide and will come exceptionally close to the Earth in 10 years' time.

"The closest encounter will take place precisely on Friday April 13, 2029," says Thackeray. "The probability of the Apophis 99942 asteroid hitting us then is only one in 100 000, but the probability of an impact may be even higher at some time in the future, as it comes close to Earth every 10 years."

Source: University of the Witwatersrand [October 02, 2019]

First human ancestors breastfed for longer than contemporary relatives

By: Thomas Schmitt Attorney on August 29, 2019 / comment : 0 Anthropology, Early Humans, Fossils, Human Evolution, South Africa

By analysing the fossilised teeth of some of our most ancient ancestors, a team of scientists led by the universities of Bristol (UK) and Lyon (France) have discovered that the first humans significantly breastfed their infants for longer periods than their contemporary relatives.

The differences in dental morphology are obvious between Australopithecus africanus (TM1518 to the left) and early Homo (SK27 to the right), but these teeth are also different in their calcium stable isotopes  compositions, unveiling group specific nursing behaviors [Credit: Vincent Balter]

The results, published in the journal Science Advances, provide a first insight into the practice of weaning that remain otherwise unseen in the fossil record.

The team sampled minute amounts from nearly 40 fossilised teeth of our South African fossil relatives, early Homo, Paranthropus robustus and Australopithecus africanus.

They measured the proportions of their stable calcium isotopes in the tooth enamel, which are a function of the mother milk intake by infants.

By reconstructing the age at tooth enamel development, they show that early Homo offspring was breastfed in significant proportions until the age of around three to four years, which likely played a role in the apparition of traits that are specific to human lineage, such as the brain development.

In contrast, infants of Paranthropus robustus, that became extinct around one million years ago and were a more robust species in terms of dental anatomy, as well as infants of Australopithecus africanus, stopped drinking sizeable proportions of mother milk in the course of the first months of life.

These differences in nursing behaviours likely come with major changes in the social structures of groups as well as the time between the birth of one child and the birth of the next.

One of the study's lead authors, Dr Theo Tacail from the University of Bristol's School of Earth Sciences, said: "The practice of weaning - the duration of breastfeeding, age at non-milk food introduction and the age at cessation of suckling - differs among the modern members of the hominid family which includes humans and modern great apes: orangutan, gorillas, chimpanzees and bonobos.

"The development of such behavioural differences likely played major roles in the evolution of the members of human lineage, being associated for instance with size and structure of social groups, brain development or demography.

"However, getting insights into these behavioural changes from fossils that are millions of years old is a challenge and, so far, little evidence allow discussing nursing practices in these fossil species.

"The findings stress the need for further exploration of calcium stables isotopes compositions in the fossil record in order to understand the co-evolution of weaning practices with other traits such as brain size or social behaviours."

Source: University of Bristol [August 29, 2019]

First direct evidence for mantle plume origin of Jurassic flood basalts in southern Africa

By: Thomas Schmitt Attorney on August 26, 2019 / comment : 0 Climate Change, Earth Science, Palaeontology, South Africa

The origin of gigantic magma eruptions that led to global climatic crises and extinctions of species has remained controversial. Two competing paradigms explain these cataclysms, either by the splitting of tectonic plates at the Earth's surface or by the impacts of hot currents, called mantle plumes, from the planetary interior.

Picrite lava outcrops at the Luenha River, Central Mozambique [Credit: Arto Luttinen]

The great Jurassic lava flows that flooded across southern Africa and parts of East Antarctica prior to the splitting of the Pangea supercontinent make up one of the largest volcanic systems on Earth. The magma eruptions caused global environmental turmoil and the extinctions of species. The rapid origin of this Karoo flood basalt province in southern Africa has been frequently associated with the melting of a large plume that ascended from the deep mantle around 180 million years ago. However, the plume model has lacked confirmation from lava compositions that preserve a geochemical 'plume signature'.

"To our knowledge, the Luenha picrites are the first lava samples that could originate from the plume source that has been previously inferred from various geological and geophysical data on the Karoo province. Therefore they allow compositional analysis of this source," says Sanni Turunen, the leading author and a doctoral student at the Finnish Museum of Natural History, which is part of the University of Helsinki.

In the case of the Luenha picrites, named after the research area near the Luenha River, the geochemical compositions indicate a hot magma source that is in many respects different from previously reported magma sources in the Karoo province. They show compositional similarities to magmas formed in other deep mantle plume-related volcanic provinces worldwide.

Olivine crystal. Primitive lavas containing magnesium-rich olivine can record early events of the magmatic system [Credit: Sanni Turunen]

"It is very important to realise that in huge and complex volcanic systems, such as the Karoo province, large amounts of magmas may be produced from several magma sources," explains Daud Jamal, professor at the Eduardo Mondlane University, in Mozambique.

"Previous studies of Karoo picrites in Africa and Antarctica by us and by other groups have suggested the generation of magmas in the upper mantle, but our new results indicate plume sources were also involved," adds Jussi Heinonen, an Academy of Finland fellow at the Department of Geosciences and Geography at the University of Helsinki.

Importantly, the Luenha picrites appear to represent the main source of the voluminous flood basalts of southern Africa. "We were fascinated to realise that the Luenha picrites revealed a type of magma source that was recently predicted using lava compositions, but which had not been confirmed by observational evidence," as characterised by Arto Luttinen, senior curator at the Finnish Museum of Natural History.

Professor Daud Jamal standing next to picrite lava outcrops on the Luenha River, Central Mozambique [Credit: Jussi Heinonen]

According to the study, the presently available data are compatible with a plume source that has retained the composition of Earth's primitive mantle remarkably well. This is quite unusual because of the 4.5 billion year evolution of the convecting mantle.

Confirmation of the age and evolution of the primitive mantle-like source of the Luenha picrites requires further constraints from future isotopic studies.

"Whatever the exact nature of the Luenha source turns out to be, we feel confident that we have uncovered rocks that help to address the complex origin of large eruptions in new detail," Turunen concludes.

The research will be published in the journal Lithos.

Source: University of Helsinki [August 26, 2019]

Shocking rate of plant extinctions in South Africa

By: Thomas Schmitt Attorney on August 22, 2019 / comment : 0 Biodiversity, Endangered Species, Environment, Natural Heritage, South Africa

Over the past 300 years, 79 plants have been confirmed extinct from three of the world's biodiversity hotspots located in South Africa -- the Cape Floristic Region, the Succulent Karoo, and the Maputuland-Pondoland-Albany corridor.

This delicate vygie, Jordaaniella anemoniflora, was first described in 1924 from plants collected near Hermanus, and it was subsequently introduced into cultivation at Kirstenbosch Botanical Garden in Cape Town. Today it is regarded as extinct in the wild [Credit: Abu Shawka/WikiCommons]

According to a study published in the journal Current Biology this week, this represents a shocking 45.4% of all known plant extinctions from 10 of the world's 36 biodiversity hotspots. Biodiversity hotspots are areas that harbour exceptionally high numbers of unique species, but at the same time they are under severe threat from human disturbance. South Africa is remarkable in that, for a relatively small country, it is home to three of these hotspots.

An international team of researchers, led by Prof Jaco Le Roux and Dr Heidi Hirsch, affiliated with the Centre for Invasion Biology (CIB) at Stellenbosch University (SU), analysed a comprehensive dataset of 291 plant extinctions since 1700 in ten biodiversity hotspots and six coldspots, covering about 15% of Earth's land surface.

The main drivers for extinctions in South Africa were found to be agriculture (49.4%), urbanisation (38%) and invasive species (22%).

Variability in predictions on the rate of plant extinctions

The results of their analysis show that, since the 1990s, extinction rates for plants over the past 300 years appear to have settled at about 1.26 extinctions per year. At its peak, however, it was at least 350 times that of historical background rates during pre-human times.

At this rate, they predict that, in the areas they studied, an additional 21 plant species will go extinct by 2030, 47 species by 2050 and 110 species by 2100.

However, these findings stand in sharp contrast to predictions from other studies that as much as half of Earth's estimated 390,000 plant species may disappear within the remainder of this century.

"This would translate into more than 49,000 extinctions in the regions we studied over the next 80 years, which seems unlikely, bar a cataclysmic event such as an asteroid strike!" they argue.

Prof Le Roux says regional datasets provide valuable data to make general inferences around plant extinctions and the drivers underlying these extinctions. There are, however, still many regions in the world without a Red List of Plants, or with outdated lists, such as Madagascar and Hawaii. These 'hottest' of hotspots were therefore not included in their analysis.

"A lack of up-to-date lists prevents us from gaining a more complete and precise picture of what we are losing, and at exactly what rate," Dr Hirsch adds.

They believe the only way to better understand the magnitude of the extinction crisis faced by plants, and biodiversity in general, is to urgently initiate regional or at least country-level biodiversity assessments.

"While our study suggests that modern plant extinctions are relatively low, it is important to keep in mind that plants are exceptionally good at 'hanging in there'. Some of them are among the longest living organisms on earth today and many can persist in low densities, even under prolonged periods of unfavourable environmental conditions. A recent report, for example, indicated that 431 plant species, previously thought to be extinct, have been rediscovered," Le Roux explains. This means that many plant species may technically not be extinct, even though they only have one or a few living individuals remaining in the wild.

Claiming extinction rates for plant species therefore remains a particularly challenging exercise.

"We need comprehensive and up-to-date datasets to make informative forecasts about the future and preservation of Earth's flora," they emphasise.

Lost plant species in South Africa's biodiversity hotspots

The first recorded species to be lost to forestry in South Africa in the 1700s was a type of fountainbush that used to grow next to streams in the Tulbagh region -- Psoralea cataracta. In 2008 it was listed as extinct on the Red List of South African Plants.

The next species to be confirmed extinct was one of the African daisies, Osteospermum hirsutum, last seen in 1775, followed by the honeybush, Cyclopia laxiflora, last seen around 1800. The reasons for their extinction are listed as agriculture, forestry and urbanisation.

More recently in 2012, an extremely rare species of vygie, Jordaaniella anemoniflora, was declared extinct in the wild after losing its battle against sprawling urbanisation and coastal developments around Strand, Macassar and Hermanus.

The Succulent Karoo has seen three confirmed plant extinctions -- a vygie, Lampranthus vanzijliae (extinct in 1921, due to agriculture and urbanisation), the legume, Leobordea magnifica (extinct in 1947 due to agriculture and grazing) and the 'knopie' Conophytum semivestitum, lost to urbanisation and mining.

For the Maputuland-Pondoland-Albany corridor, twenty species have been confirmed extinct, mainly due to agriculture and utilisation, and include Adenia natalensis (1865), Barleria natalensis (1890) and more recently, Pleiospilos simulans (2007).

In conclusion

The researchers emphasise that biodiversity loss, together with climate change, are the biggest threats faced by humanity: "Along with habitat destruction, the effects of climate change are expected to be particularly severe on those plants not capable of dispersing their seeds over long distances," they conclude.

Author: Wiida Fourie-Basson | Source: Stellenbosch University South Africa [August 22, 2019]

New species of early dinosaur described from South Africa

By: Thomas Schmitt Attorney on August 05, 2019 / comment : 0 Dinosaurs, Fossils, Palaeontology, South Africa

A new dinosaur species has been discovered after laying misidentified in a museum collection for 30 years. Prof Paul Barrett, a dinosaur researcher at the Natural History Museum, is part of a team that reassessed the specimen, which is held at the University of Witwatersrand, Johannesburg. Along with his colleagues in South Africa, and led by Paul's Ph.D. student Kimberley Chapelle, they recognised it not only as a new species of sauropodomorph, but an entirely new genus. The specimen has now been named Ngwevu intloko which means "grey skull" in the Xhosa language, chosen to honour South Africa's heritage.

The skull has been in the collection for over 30 years, but was misidentified [Credit: © Jonah Choiniere]

Prof Barrett explains, "This is a new dinosaur that has been hiding in plain sight. "The specimen has been in the collections in Johannesburg for about 30 years, and lots of other scientists have already looked at it. But they all thought that it was simply an odd example of Massospondylus."

Massospondylus was one of the first dinosaurs to reign at the start of the Jurassic period. Regularly found throughout southern Africa, these animals belonged to a group called the sauropodomorphs and eventually gave rise to the sauropods, a group containing the Natural History Museum's iconic dinosaur cast Dippy. Researchers are now starting to look closer at many of the supposed Massospondylus specimens, believing there to be much more variation than first thought.

Micro-CT scan of Ngwevu intloko skull 2  [Credit: Kimberley Chapelle]

Kimberley Chapelle explains why the team were able to confirm that this specimen was a new species, "In order to be certain that a fossil belongs to a new species, it is crucial to rule out the possibility that it is a younger or older version of an already existing species. This is a difficult task to accomplish with fossils because it is rare to have a complete age series of fossils from a single species. Luckily, the most common South African dinosaur Massospondylus has specimens ranging from embryo to adult! Based on this, we were able to rule out age as a possible explanation for the differences we observed in the specimen now named Ngwevu intloko."

A good deal of the rest of the animal's skeleton also got fossilised [Credit: © Kimberley Chapelle]

The new dinosaur has been described from a single fairly complete specimen with a remarkably well-preserved skull. The new dinosaur was bipedal with a fairly chunky body, a long slender neck and a small, boxy head. It would have measured three metres from the tip of its snout to the end of its tail and was likely an omnivore, feeding on both plants and small animals.

The findings will help scientists better understand the transition between the Triassic and Jurassic period, around 200 million years ago. Known as a time of mass extinction it now seems that more complex ecosystems were flourishing in the earliest Jurassic than previously thought.

By taking slices of the fossilised bones, the team could estimate the animal's age [Credit: © Kimberley Chapelle]

"This new species is interesting," says Prof Barrett, 'because we thought previously that there was really only one type of sauropodomorph living in South Africa at this time. We now know there were actually six or seven of these dinosaurs in this area, as well as variety of other dinosaurs from less common groups. It means that their ecology was much more complex than we used to think. Some of these other sauropodomorphs were like Massospondylus, but a few were close to the origins of true sauropods, if not true sauropods themselves."

Ngwevu intloko would have looked similar to the Massospondylus seen here, with a chonky body and a long, slender neck [Credit: Nobu Tamura/WikiCommons]

This work shows the value of revisiting specimens in museum collections, as many news species are probably sitting unnoticed in cabinets around the world.

The new paper is published in the journal PeerJ.

Source: Natural History Museum [August 05, 2019]

Drop of ancient seawater rewrites Earth's history

By: Thomas Schmitt Attorney on August 01, 2019 / comment : 0 Earth Science, Geology, Palaeontology, South Africa

The remains of a microscopic drop of ancient seawater has assisted in rewriting the history of Earth's evolution when it was used to re-establish the time that plate tectonics started on the planet.

Unique texture of komatiite lava flows from the Barberton greenstone belt. The highly elongate crystals of olivine formed at an eruption temperature of over 1600°C - over 300 degrees hotter than current day lavas on Hawaii [Credit: Wits University]

Plate tectonics is Earth's vital - and unique - continuous recycling process that directly or indirectly controls almost every function of the planet, including atmospheric conditions, mountain building (forming of continents), natural hazards such as volcanoes and earthquakes, formation of mineral deposits and the maintenance of our oceans. It is the process where the large continental plates of the planet continuously move, and the top layers of the Earth (crust) are recycled into the mantle and replaced by new layers through processes such as volcanic activity.

Where it was previously thought that plate tectonics started about 2.7 billion years ago, a team of international scientists used the microscopic leftovers of a drop of water that was transported into the Earth's deep mantle - through plate tectonics - to show that this process started 600 million years before that. An article on their research that proves plate tectonics started on Earth 3.3 billion years ago was published in the high impact academic journal Nature.

"Plate tectonics constantly recycles the planet's matter, and without it the planet would look like Mars," says Professor Allan Wilson from the Wits School of Geosciences, who was part of the research team.

"Our research showing that plate tectonics started 3.3 billion years ago now coincides with the period that life started on Earth. It tells us where the planet came from and how it evolved."

A diagrammatic representation of the Earth in the Archaean showing subducted ocean floor carrying its chemical signature into the deep mantle. The signature which includes water and chlorine is preserved in melt inclusions contained within olivine and carried back up to surface within komatiite lava flows [Credit: Wits University]

Earth is the only planet in our solar system that is shaped by plate tectonics and without it the planet would be uninhabitable.

For their research, the team analysed a piece of rock melt, called komatiite - named after the type occurrence in the Komati river near Barberton in Mpumalanga - that are the leftovers from the hottest magma ever produced in the first quarter of Earth's existence (the Archaean). While most of the komatiites were obscured by later alteration and exposure to the atmosphere, small droplets of the molten rock were preserved in a mineral called olivine. This allowed the team to study a perfectly preserved piece of ancient lava.

"We examined a piece of melt that was 10 microns (0.01mm) in diameter, and analysed its chemical indicators such as H2O content, chlorine and deuterium/hydrogen ratio, and found that Earth's recycling process started about 600 million years earlier than originally thought," says Wilson. "We found that seawater was transported deep into the mantle and then re-emerged through volcanic plumes from the core-mantle boundary."

The research allows insight into the first stages of plate tectonics and the start of stable continental crust.

"What is exciting is that this discovery comes at the 50th anniversary of the discovery of komatiites in the Barberton Mountain Land by Wits Professors, the brothers Morris and Richard Viljoen," says Wilson.

Source: University of the Witwatersrand [August 01, 2019]

Places we once called home

By: Thomas Schmitt Attorney on July 24, 2019 / comment : 0 Africa, Anthropology, Early Humans, South Africa

There was a time when the laughter of Stone Age children filled the Sibudu Cave. About 64 000 years ago, a child was part of a hunter-gatherer family that took temporary shelter in this cave, which lies close to the KwaZulu-Natal town of KwaDukuza.

Klipdrift Cave and Klipdrift Shelter, located in the De Hoop Nature Reserve, southern Cape, South Africa, have elicited findings from roughly 65 000 years ago to 59 400 years ago, including a hominin molar, floral remains, and more than 95 pieces of eggshell engraved with diverse, abstract patterns [Credit: Wits University]

When this child died, it didn't leave its bones in the cave for discovery by archaeologists of the future—the only thing left behind was a milk tooth. In modern times, the mythological tooth fairy whisks away children's teeth, but we don't know what the rituals were back then.

Professor Lyn Wadley, archaeologist in the School of Geography, Archaeology and Environmental Studies at Wits, is thankful that this tooth—and those of other children—ended up on the cave floor, because they reveal just how much humans have changed since we gave up our hunter-gatherer ways.

Teeth-bricks for tooth fairies

"The interesting thing about the teeth is that we know this is a home-base, because there were children there, and that is quite nice," says Wadley. "But the [research] papers also suggest that the teeth were perhaps a little bit larger than the teeth of children today. So maybe the people were a little more robust." These children perhaps had access to better diets than we have today.

"A lot of people have pointed out that moving to the diet that farming people had was not necessarily improving the health of people. There are higher carbohydrates compared to protein, and with it comes poorer tooth quality and poorer bone quality," says Wadley.

"Part of the reason why hunter-gatherers had a better diet was not because of what they were eating, but the fact that groups were smaller and this meant that people had better access to quality plant foods."

Cave sites like Sibudu are providing scientists with a peek into what our earliest homes looked like. These glimpses give archaeologists not only a better understanding of how our ancestors lived, but also how we evolved into the species we are today.

No fixed abode

From the deep past, scientists are uncovering the stuff that makes us human—from forward planning, to the very beginnings of art. One of these discoveries is that our ancestors were not homebodies. We were wanderers who kept our stays short.

At Blombos Cave in the southern Cape, Professor Christopher Henshilwood and his team have been sifting through the leftovers of these brief visits that go back over 100 000 years. Henshilwood holds the DST/NRF SARChI Chair in The Origins of Modern Human Behaviour at Wits University and is the Director of the Centre for Early Sapiens Behaviour (SapienCE), a new Centre of Excellence at the University of Bergen in Norway.

"We think that Blombos, at some stages, was occupied for just one night. We are seeing what looks like a ghost of a visit. You find a few shellfish, a tiny little fire and almost nothing else. And then there is nothing after that," says Henshilwood.

The world's first hashtag

Some of the discoveries at Blombos have advanced our insight into early human cognitive development.

Last year, Henshilwood and his team revealed a silcrete (hardened mineral crust) flake to the world that had six crosshatched lines on it—much like a hashtag. A human, using an ochre crayon, 73 000 years ago, had drawn these lines.

It took two years of scientific testing to come to the conclusion that this is the earliest example of a drawing, says Henshilwood.

Credit: Wits University

Even this long ago, at Blombos Cave and Klipdrift Shelter, another of the sites excavated by Henshilwood's team, you can see that people bring to the site what they need to carry out a particular task. "These people are capable of planning, they have templates or recipes in their heads, for what they need in the cave," says Henshilwood. "This is one of the markers of behavioural modernity."

When that artist made that drawing on that piece of silcrete, he or she would have been one of only about 10 000 humans living in the whole of Africa.

There are other artifacts left at these temporary homes that point to our ancestors being highly intelligent problem-solvers. At Border Cave on the Swaziland border, Wadley and Dr. Lucinda Backwell found traces of poison on a thin wooden stick that dates back at least 20 000 years. The poison is thought to have been used on arrows.

Homemakers and hunter-gatherers

Wadley believes that snares were also used by the people who periodically made Sibudu their home. But it is the presence of buffalo bones in the cave that points to team work, which would have probably included women.

"If you look at your typical hunter-gatherer group—let us say there are 60 people—more than half of those are going to be children who wouldn't take part in the hunt. Then you have some old people. So if you break down the demographics, you might only end up with 10 able-bodied male hunters," says Wadley. "If you want to manage a dangerous animal hunt, you are going to have to bring in the women too, even if they are just beaters."

What archaeologists are rarely seeing is evidence of other homes away from the caves and rock shelters. These rudimentary shelters would have been where our ancestors slept for a couple of nights before moving on.

Home security

Professor Robert Thornton, social anthropologist in the School of Social Sciences at Wits, says that three basic needs would have driven early humans into utilizing and making shelters. "Our earliest habitats were primarily designed to keep our food safe, secondarily to keep the goggas [insects] and other stuff away, and finally for climate control. But before that, it was important to keep your view open," he says.

"People imagined that early man lived in caves, or they had to have four walls around them, but that is one of the worst things you can do, because you cannot see the rest of your environment. You want to be in the open, you want to see 360 degrees, particularly when there are big cats around."

But it is in the caves where the treasures lie. It is here that the artifacts are best preserved, and where they accumulate in layers of earth that sometimes stretch back hundreds of thousands of years.

At Blombos, Henshilwood hopes he might one day find the rest of that silcrete flake that would reveal more of that earliest drawing.

But there are more artifacts to be found in places we once called home that will give us insight into a time when humans first began to act and think like we do.

Author: Shaun Smillie | Source: Wits University [July 24, 2019]

8,000-year-old petroglyphs found in earth's largest meteor crater

By: Thomas Schmitt Attorney on June 13, 2019 / comment : 0 Archaeology, Early Humans, Earth Science, Geology, South Africa

Leading South African scientists from the University of the Free State are about to undertake research into the destruction caused by a huge ancient meteorite that could hold clues critical to the history, mechanisms and consequences of meteorite strikes on earth and elsewhere in the Solar System. The results of this work could mean a better understanding of the effects of such impacts and the greater safety of the earth.

One of the carvings found on the impact crater dyke [Credit: University of the Free State]

The vast crater is also fascinating for its human interest from early man who used it as a centre of cultural importance and left rock carvings as proof of their presence. The site was of great spiritual significance, comparable to the stone circles of Stonehenge in the UK. The Khoi-San patently understood that the rock remains found on the surface were unique and important.

The University of the Free State is fortunate to be situated only 180 miles from the largest meteorite crater, which has an initial diameter of 300 kilometers (186.4 miles) and at over two billion years old is the oldest impact crater on Earth – known as the Vredefort impact structure. The meteorite that made the impact was travelling at 70,000 kilometres (43,495.98 miles) per hour when it struck the earth.

The effect on the earth has lasted millennia in a dynamic, changing process. The recent meteor impact discovery in Scotland is tiny by comparison. Had man been present at the time of the Scottish impact it would have destroyed the whole Scots community, whereas the Vredefort impact would have led to human extinction on earth.

Carving appears to show a horse [Credit: University of the Free State]

The University of the Free State study of the Vredefort impact structure will look in particular at the Granophyre dykes, the only remnants of the now eroded impact melt sheet that intruded downwards through fractures in the crater floor.

Gold in the Crater

In addition to the planetary-scale importance of impact events, some impact craters are connected with ore deposits. The Vredefort impact structure in South Africa is situated in the center of the Witwatersrand goldfields, and the richness, location, and accessibility of the gold mineralisation are clearly connected to the impact structure, which moved the gold deposits around, concentrating it, say the UFS scientists studying the crater. The impact structure, therefore, influenced economic interest in the area, and as a result created the city of Johannesburg, one of the largest cities on the African continent.

An international team of scientists is being led by principal investigator Dr. Matthew S. Huber of the University of the Free State in Bloemfontein, Faculty of Natural and Agricultural Sciences, Department of Geology, who says: “As impact events can potentially represent a threat to life with the ability to alter the development of entire planets, it is critical that we develop a better understanding of their history, mechanisms, and consequences. By studying the traces of impact events on Earth, we can reconstruct the mechanisms of such processes, and gain greater understanding of our own ecosystem and origin.”

Carving found in the Vredefort impact crater [Credit: University of the Free State]

He adds: “The Vredefort impact was massive – it was larger than the impact that killed the dinosaurs. If it happened today, civilization might be at an end. We only know of three such impact craters preserved on Earth: the Chicxulub crater that killed the dinosaurs, the Sudbury crater in Canada, and the Vredefort crater. What is really unique about Vredefort is that we get to see the deep architecture below these massive impact craters, and those deep rocks tell not only the story of what happened at the moment of impact, but also how those rocks adjusted and shifted for thousands of years after the impact.”

“We are pretty sure that the asteroid that caused the Vredefort impact event was about 10-15 kilometres (6.2-9.3 miles) in diameter. Many space programs around the world are tracking asteroids that are potentially dangerous to life on Earth. These programs have discovered that there are hundreds of asteroids that are at least 1 km in diameter that would cause massive devastation if they impacted the earth. Fortunately, at the moment, none of these asteroids appears to be on a collision course with us!”

And on the subject of early man’s link to the crater, he says: “We suspect that one reason the San took interest in the crater’s Granophyre dykes was that the dyke resembles the shape of the Rain Snake. The location of the dyke on top of a hill, near a body of water, and in the shape of an important deity probably brought them there so that they could perform rainmaking rituals, and possibly other important cultural activities. We hope that detailed investigation will show us more about how the site might have been utilised.”

Image showing a hippopotamus carved by the San people around 8,000 years ago [Credit: University of the Free State]

Observations of rocky bodies such as the Moon, Mars, and asteroids have revealed that impact craters are common throughout the Solar System. Meteorite impacts have also left scars over the surface of the Earth, and some of these impact events have had major effects on our planet. A powerful meteorite impact 65 million years ago, known as the Chicxulub impact event, led to the extinction of 65% of life on earth, including the dinosaurs.

On Earth, erosion and active plate tectonics remove meteorite impact craters from the surface comparatively quickly. When impact craters are exposed at the surface, they are often utilised by people living in the area for cultural purposes.

The structure is easily accessible for sampling and research, providing an opportunity to study this impact crater. Vredefort is an ideal impact structure to study, as it is deeply eroded, showing features not seen elsewhere on Earth, is accessible at the surface, and has not been modified by any major tectonic event, due to its position on the stable Kaapvaal craton. Additionally, it has cultural significance, with early man, Khoi-San rock art, rock shelters, pottery, and engravings. This provides opportunities to enhance knowledge of South Africa’s “First Peoples”.

Some of the crater's multiple rims have eroded away, but from space, what is left is clear [Credit: University of the Free State]

Research Objectives 

The University of the Free State will combine geological investigations with cultural investigations to provide a unique perspective on the Vredefort impact structure that is both scientifically advanced and grounded in humanity.

UNESCO World Heritage Site

The Vredefort impact structure is a UNESCO world heritage site, based on its socio-cultural, aesthetic, conservational, historical and scientific significance. In addition, this site has traces of San rock art indicative of material remains attached to a specific socio-cultural reality. These rock art sites form an integral part of the South African cultural heritage landscape.

Granophyre Dykes

The proposed University of the Free State study of the Vredefort impact structure will look in particular at the Granophyre dykes, the only remnants of the now eroded impact melt sheet that intruded downwards through fractures in the crater floor. Because the impact melt intruded downwards, capturing rock fragments on its way, it can provide samples of rock formations that are long eroded and are otherwise not accessible.

Granophyre dyke [Credit: University of the Free State]

Such samples allow observations of shock microstructures, formed in target rocks that were located near the earth’s early surface at the time of impact. Studying the granophyre dykes can answer many geological questions. The overarching questions the UFS research team want to answer are: 1) what did the Vredefort structure look like? And 2) what was it composed of before it was eroded?

These dykes, exposed by erosion, have been exploited by the Khoi-San culture as ceremonial sites, so from a heritage perspective, the above stated objectives offer great potential to contribute also to the existing body of knowledge of the scientific and aesthetic significance of this heritage site.

By studying the impact structure at both macro- and micro-scales, the UFS team will make important contributions about the knowledge of impact craters, the processes that take place during large impact events, and processes and outcomes attached to the scope of heritage.

Image showing the outline of the dyke where the carvings were found [Credit: University of the Free State]

These geological observations and results can then be applied to other planetary bodies, giving us a greater understanding of the Moon, Mars, and other planets. In terms of the heritage scope, our outcomes will contribute to the body of anthropological knowledge on the socio-cultural reality of the Khoi-San within the Free State as well as the concept of “living” heritage.

Anthropological literature on the San is limited to the South African Provinces of the Western Cape and the Northern Cape, as well as countries such as Botswana and Namibia. Anthropological understanding of the San in the Free State and specifically in relation to the concept heritage is lacking.

Expected results of the Project

The new data generated from this project will help the team to constrain the stages and processes that occurred during the formation and subsequent development of the impact structure. This data will fill in gaps in the scientific literature and have global implications, with results being applicable to not only other impact structure on Earth, but also on the Moon and Mars.

The work will grow the scientific understanding of impact-cratering processes. It will furthermore contribute to the scholarly understanding of the heritage significance of this site with specific reference to the Khoi-San.

Source: University of the Free State [June 13, 2019]

More on Earliest evidence of the cooking and eating of starch found in South Africa

By: Thomas Schmitt Attorney on May 17, 2019 / comment : 0 Africa, Archaeology, Early Humans, South Africa

New discoveries made at the Klasies River Cave in South Africa's southern Cape, where charred food remains from hearths were found, provide the first archaeological evidence that anatomically modern humans were roasting and eating plant starches, such as those from tubers and rhizomes, as early as 120,000 years ago.

The Klasies River cave in the southern Cape of South Africa [Credit: Wits University]

The new research by an international team of archaeologists, published in the Journal of Human Evolution, provides archaeological evidence that has previously been lacking to support the hypothesis that the duplication of the starch digestion genes is an adaptive response to an increased starch diet.

"This is very exciting. The genetic and biological evidence previously suggested that early humans would have been eating starches, but this research had not been done before," says Lead author Cynthia Larbey of the Department of Archaeology at the University of Cambridge. The work is part of a systemic multidisciplinary investigation into the role that plants and fire played in the lives of Middle Stone Age communities.

The interdisciplinary team searched for and analysed undisturbed hearths at the Klasies River archaeological site.

The Klasies River cave in the southern Cape of South Africa [Credit: Wits University]

"Our results showed that these small ashy hearths were used for cooking food and starchy roots and tubers were clearly part of their diet, from the earliest levels at around 120,000 years ago through to 65,000 years ago," says Larbey. "Despite changes in hunting strategies and stone tool technologies, they were still cooking roots and tubers."

Professor Sarah Wurz from the School of Geography, Archaeology and Environmental Studies at the University of the Witwatersrand in Johannesburg, South Africa (Wits University) and principal investigator of the site says the research shows that "early human beings followed a balanced diet and that they were ecological geniuses, able to exploit their environments intelligently for suitable foods and perhaps medicines".

By combining cooked roots and tubers as a staple with protein and fats from shellfish, fish, small and large fauna, these communities were able to optimally adapt to their environment, indicating great ecological intelligence as early as 120 000 years ago.

Cynthia Larbey points to an area where parenchyma were found in 65,000 year old hearths at Klasies River Cave [Credit: Wits University]

"Starch diet isn't something that happens when we started farming, but rather, is as old as humans themselves," says Larbey. Farming in Africa only started in the last 10 000 years of human existence.

Humans living in South Africa 120 000 years ago formed and lived in small bands.

"Evidence from Klasies River, where several human skull fragments and two maxillary fragments dating 120 000 years ago occur, show that humans living in that time period looked like modern humans of today. However, they were somewhat more robust," says Wurz.

Klasies River is a very famous early human occupation site on the Cape coast of South Africa excavated by Wurz, who, along with Susan Mentzer of the Senckenberg Institute and Eberhard Karls Universit?t Tübingen, investigated the small (c. 30cm in diameter) hearths.

Source: University of the Witwatersrand [May 17, 2019]

Statistical study finds it unlikely South African fossil species is ancestral to humans

By: Thomas Schmitt Attorney on May 08, 2019 / comment : 0 Anthropology, Fossils, Human Evolution, South Africa

Statistical analysis of fossil data shows that it is unlikely that Australopithecus sediba, a nearly two-million-year-old, apelike fossil from South Africa, is the direct ancestor of Homo, the genus to which modern-day humans belong.

Fossil casts of Australopithecus afarensis (left), Homo habilis (centre), and Australopithecus sediba (right) [Credit: Matt Wood, UChicago]

The research by paleontologists from the University of Chicago, published this week in Science Advances, concludes by suggesting that Australopithecus afarensis, of the famous "Lucy" skeleton, is still the most likely ancestor to the genus Homo.

The first A. sediba fossils were unearthed near Johannesburg in 2008. Hundreds of fragments of the species have since been discovered, all dating to roughly two million years ago. The oldest known Homofossil, the jawbone of an as yet unnamed species found in Ethiopia, is 2.8 million years old, predating A. sediba by 800,000 years.

Despite this timeline, the researchers who discovered A. sediba have claimed that it is an ancestral species to Homo. While it is possible that A. sediba (the hypothesized ancestor) could have postdated earliest Homo (the hypothesized descendant) by 800,000 years, the new analysis indicates that the probability of finding this chronological pattern is highly unlikely.

"It is definitely possible for an ancestor's fossil to postdate a descendant's by a large amount of time," said the study's lead author Andrew Du, PhD, who will join the faculty at Colorado State University after concluding his postdoctoral research in the lab of Zeray Alemseged, PhD, the Donald M. Pritzker Professor of Organismal and Biology and Anatomy at UChicago.

"We thought we would take it one step further to ask how likely it is to happen, and our models show that the probability is next to zero," Du said.

Du and Alemseged also reviewed the scientific literature for other hypothesized ancestor-descendant relationships between two hominin species. Of the 28 instances they found, only one first-discovered fossil of a descendant was older than its proposed ancestor, a pair of Homo species separated by 100,000 years, far less than the 800,000 years separating A. sediba and earliest Homo. For context, the average lifespan of any hominin species is about one million years.

"Again, we see that it's possible for an ancestor's fossil to postdate its descendant's," Du said. "But 800,000 years is quite a long time."

Alemseged and Du maintain that Australopithecus afarensisis a better candidate for the direct ancestor of Homofor a number of reasons. A. afarensis fossils have been dated up to three million years old, nearing the age of the first Homo jaw. Lucy and her counterparts, including Selam, the fossil of an A. afarensischild that Alemseged discovered in 2000, were found in Ethiopia, just miles from where the Homo jaw was discovered. The jaw's features also resemble those of A. afarensis closely enough that one could make the case it was a direct descendant.

"Given the timing, geography and morphology, these three pieces of evidence make us think afarensisis a better candidate than sediba," Alemseged said. "One can disagree about morphology and the different features of a fossil, but the level of confidence we can put in the mathematical and statistical analyses of the chronological data in this paper makes our argument a very strong one."

Source: University of Chicago Medical Center [May 08, 2019]

Earliest evidence of the cooking and eating of starch found in South Africa

By: Thomas Schmitt Attorney on April 24, 2019 / comment : 0 Archaeology, Early Humans, South Africa

New research published in the Journal of Human Evolution provides the earliest archaeological evidence that anatomically modern humans were roasting and eating plant starches as early as 120,000 years ago.

Charred food remains from hearths in Klasies River Caves, South Africa [Credit: C. Larbey]

Lead author Cynthia Larbey of the Department of Archaeology at the University of Cambridge says, “Our findings provide the archaeological evidence that has previously been lacking to support the hypothesis that the duplication of the starch digestion genes is an adaptive response to an increased starch diet.”

Organic tissues and substances from the upper hearth in Klasies River Caves, South Africa, under reflected and UV light [Credit: C. Larbey]

“This is very exciting. The genetic and biological evidence previously suggested that early humans would have been eating starches, but this research had not been done before. So, at Klasies River we took a team approach, firstly to find and analyse undisturbed hearths and secondly, to take botanical samples from those hearths and compare findings.”

Researcher Cynthia Larbey walks to the mouth of one of the Klasies River Caves, South Africa, 2015 [Credit: C. Larbey]

Klasies River is a very famous early human occupation site on the Cape coast of South Africa. In these caves, co-author Susan Mentzer of Eberhard Karls Universitӓt Tübingen and the University of Arizona, identified small (c. 30cm in diameter) hearths.

Left: The main cave site at Klasies River, South Africa; Right: Main site plan showing sample locations [Credit: C. Larbey & D. Redhouse]

“The results show these small ashy hearths were used for cooking food and starchy roots and tubers were clearly part of their diet, both from the earliest levels at around 120,000 years ago through to 65,000 years ago. So, despite changes in hunting strategies and stone tool technologies, they are still cooking roots and tubers.”

Map showing location of Klasies Cave, South Africa [Credit: C. Larbey & D. Redhouse]

The wider implications of this new research include a glimpse into early human migration. The ability to use cooked roots and tubers as a staple provided greater adaptability for humans to colonise new regions of the world.

Larbey adds, “Starch diet isn’t something that happens when we start farming, but rather, is as old as humans themselves.”

Source: University of Cambridge [April 24, 2019]