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25 July 2019 | Story Leonie Bolleurs | Photo Leonie Bolleurs
Plant Sciences Congress
At a public seminar, Understanding human evolution through the study of past environments in the Free State, presented by the UFS Department of Plant Sciences, were, from the left, front: Kristen Wroth, Britt Bousman; back: Prof Louis Scott, mentor in the UFS Department of Plant Sciences, and Michael Toffolo.

Florisbad, a thermal spring situated 45 km northwest of Bloemfontein on the edge of a large dry saltpan, is a well-known fossil site that used to be a large lake where giant buffalo, blue wildebeest, and hippos roamed thousands of years ago. Today, this fossil-bearing spring is not only a tourist attraction and a venue for weddings, but also an established quaternary research station that has attracted several palaeo-scientists since the 1930s, following the discovery of a remarkable human cranium and other fauna. 

Studies of past environments 

Three international researchers studying different aspects of archaeology at this and other sites in the Free State, recently presented lectures at the UFS to a multidisciplinary group of academics in plant sciences, geology, geography, and environmental management.

These lectures are part of the ongoing collaboration regarding fossil plant (pollen), fauna, and archaeological studies between the University of the Free State (UFS), the National Museum, and universities abroad.

Florisbad, a key site for understanding the appearance of modern environments as well as modern humans in Southern Africa, is the focus of the investigations of all three visiting scientists, aiming to provide a better understanding of past Free State environments where human evolution has taken place.

Michael Toffolo, a junior research chair from the University of Bordeaux Montaigne in France, focuses on the reconstruction of site-formation processes, palaeo-environments, and ancient human activities based on the study of the micro-morphology of archaeological deposits. He has been working in Southern Africa since 2013. The title of his lecture was: Reconstructing Pleistocene environments in the Free State by looking at the microscopic sedimentary record. 

Fluoride-preserved bones

Florisbad is widely known for the discovery of an archaic modern human skull of c. 260 000 years old. According to Toffolo, the human probably died, and the remains was left at the spring by the hyenas. The bones consequently absorbed fluoride from the spring water, which counteracted decomposition and helped to preserve it. 

Britt Bousman talked about middle and late Pleistocene terraces and archaeology in the Modder River Valley. He has worked in Southern Africa for the past 43 years and started his collaboration with researchers from the UFS and the National Museum in 1985. They have worked together at several sites, investigating palaeo-environments. Bousman teaches Archaeology in the Department of Anthropology at the Texas State University. 

While most scientists study early human records in rock shelters, especially those near the coast where seafood was harvested by prehistoric people, he is one of only a few researchers who studies the evolution of early human behaviour in central South Africa in the context of their activities in the open environment. 

“Rock shelters are good spaces for human behaviour,” says Bousman. He believes, however, that the Modder River area is a better space to study how humans have survived on the land under changing climatic conditions in the long term; for example, how they hunted and slaughtered animals. This can be seen from the many artefacts they left, such as spearheads, scrapers, etc. Interesting animal remains were also found, such as the bones of an extinct giant zebra at the Erfkroon site along the Modder River, with a head measuring 63 cm compared to that of a current zebra, which measures 54 cm. The only complete horn core of an extinct giant wildebeest was also found at the site. 

The first chemists

According to Bousman, technology changed in the Stone Age and included the production of more grinding stones, indicating that humans collected plants and grinded them. Observations of modern plant-collecting activities suggested that not many plant foods needed grinding. Bousman proposes that different plant components may have been grinded for medicinal mixtures, therefore these ancestors may have assumed the role of chemists. 

Kristen Wroth, a postdoctoral researcher in the Geoarchaeology Working Group at the University of Tübingen, Germany, presented a lecture on early human-environment interactions and ancient pyro technology. She uses a suite of micro-archaeological techniques such as phytolith (microscopic plant silica) analysis, micromorphology, and FTIR to understand both human and Neanderthal behaviour and to reconstruct how local environments have changed in space and through time.


News Archive

UFS physicists publish in prestigious Nature journal
2017-10-16

Description: Boyden Observatory gravitational wave event Tags: Boyden Observatory, gravitational wave event, Dr Brian van Soelen, Hélène Szegedi, multi-wavelength astronomy 
Hélène Szegedi and Dr Brian van Soelen are scientists in the
Department of Physics at the University of the Free State.

Photo: Charl Devenish

In August 2017, the Boyden Observatory in Bloemfontein played a major role in obtaining optical observations of one of the biggest discoveries ever made in astrophysics: the detection of an electromagnetic counterpart to a gravitational wave event.
 
An article reporting on this discovery will appear in the prestigious science journal, Nature, in October 2017. Co-authors of the article, Dr Brian van Soelen and Hélène Szegedi, are from the Department of Physics at the University of the Free State (UFS). Both Dr Van Soelen and Szegedi are researching multi-wavelength astronomy.
 
Discovery is the beginning of a new epoch in astronomy
 
Dr van Soelen said: “These observations and this discovery are the beginning of a new epoch in astronomy. We are now able to not only undertake multi-wavelength observations over the whole electromagnetic spectrum (radio up to gamma-rays) but have now been able to observe the same source in both electromagnetic and gravitational waves.”
 
Until recently it was only possible to observe the universe using light obtained from astronomical sources. This all changed in February 2016 when LIGO (Laser Interferometer Gravitational-Wave Observatory) stated that for the first time they had detected gravitational waves on 14 September 2015 from the merger of two black holes. Since then, LIGO has announced the detection of two more such mergers. A fourth was just reported (27 September 2017), which was the first detected by both LIGO and Virgo. However, despite the huge amount of energy released in these processes, none of this is detectable as radiation in any part of the electromagnetic spectrum. Since the first LIGO detection astronomers have been searching for possible electromagnetic counterparts to gravitational wave detections. 
 
Large international collaboration of astronomers rushed to observe source
 
On 17 August 2017 LIGO and Virgo detected the first ever gravitational waves resulting from the merger of two neutron stars. Neutron star mergers produce massive explosions called kilonovae which will produce a specific electromagnetic signature. After the detection of the gravitational wave, telescopes around the world started searching for the optical counterpart, and it was discovered to be located in an elliptical galaxy, NGC4993, 130 million light years away. A large international collaboration of astronomers, including Dr Van Soelen and Szegedi, rushed to observe this source.
 
At the Boyden Observatory, Dr Van Soelen and Szegedi used the Boyden 1.5-m optical telescope to observe the source in the early evening, from 18 to 21 August. The observations obtained at Boyden Observatory, combined with observations from telescopes in Chile and Hawaii, confirmed that this was the first-ever detection of an electromagnetic counterpart to a gravitational wave event. Combined with the detection of gamma-rays with the Fermi-LAT telescope, this also confirms that neutron star mergers are responsible for short gamma-ray bursts.  
 
The results from these optical observations are reported in A kilonova as the electromagnetic counterpart to a gravitational-wave source published in Nature in October 2017.
 
“Our paper is one of a few that will be submitted by different groups that will report on this discovery, including a large LIGO-Virgo paper summarising all observations. The main results from our paper were obtained through the New Technology Telescope, the GROND system, and the Pan-STARRS system. The Boyden observations helped to obtain extra observations during the first 72 hours which showed that the light of the source decreased much quicker than was expected for supernova, classifying this source as a kilonova,” Dr Van Soelen said.

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