Saturday, January 11, 2020

Early Humans Revealed to Have Engineered Optimized Stone Tools at Olduvai Gorge

Early Stone Age populations living between 1.8 – 1.2 million years ago engineered their stone tools in complex ways to make optimised cutting tools, according to a new study by Kent and UCL.

The research, published in the Journal of Royal Society Interface on 8 January, shows that Palaeolithic hominins selected different raw materials for different stone tools based on information about how sharp, durable and efficient those materials were. They made these decisions in conjunction with information about the length of time the tools would be used for and the force with which they could be applied. This reveals previously unseen complexity in the design and production of stone tools during this period.
Credit: University of Kent


The research was led by Dr Alastair Key, from the School of Anthropology and Conservation, and is based on evidence from mechanical testing of the raw materials and artefacts found at Olduvai Gorge in Tanzania – one of the world’s most important sites for human origins research.

Dr Key collaborated with Dr Tomos Proffitt from UCL Institute of Archaeology and Professor Ignacio de la Torre of the CSIC-Centro de Ciencias Humanas y Sociales in Madrid, for the study.

Their research, which employed experimental methods more commonly used in modern engineering research, shows that hominins preferentially selected quartzite, the sharpest but least durable stone type at Olduvai for flake tools; a technology thought to have been used for expedient, short-lived cutting activities.

Chert, which was identified as being highly durable and nearly as sharp as quartzite, was only available to hominins for a short 200,000 year period. Whenever it was available chert was favoured for a variety of stone tool types due to its ability to maximise cutting performance over extended tool-use durations.

Other stone types, including highly durable lavas, were available at Olduvai, however their use varied according to factors such as how long a tool was intended to be used for, a tool’s potential to create high cutting forces, and the distance hominins had to travel to raw material sources.

Olduvai Gorge
Credit: University of Kent

The study reveals a level of complexity and flexibility in stone tool production previously unseen at this time. Earlier research had demonstrated Early Stone Age populations in Kenya to select highly durable stone types for tools, but this is the first time cutting edge sharpness has been able to be considered. By selecting the material best suited to specific functional needs, hominins optimised the performance of their tools and ensured a tool’s efficiency and ‘ease-of-use’ was maximised.

Dr Key, Lecturer in Biological Anthropology, said: ‘Why Olduvai populations preferentially chose one raw material over another has puzzled archaeologists for more than 60 years. This has been made all the more intriguing given that some stone types, including lavas and quartzite, were always available.

‘What we’ve been able to demonstrate is that our ancestors were making quite complex decisions about which raw materials to use, and were doing so in a way that produced tools optimised for specific circumstances. Although we knew that later hominin species, including our own, were capable of such decisions, it’s amazing to think that populations 1.8 – 1.2 million years ago were also doing so.’

Dr Proffitt added: ‘Early hominins during the Oldowan were probably using stone flakes for a variety of tasks. Mostly for butchering animals whilst scavenging, but also probably for cutting various plants and possibly even shaping wood. A durable cutting edge would have been an important factor when using these tools.

‘There are many modern analytical techniques used in material sciences and engineering that can be used to interrogate the archaeological record, and may provide new insights into the mechanical properties of such tools and artefacts. By understanding the way that these tools work and their functional limits it allows archaeologists to build up a greater understanding of the capabilities of our earliest ancestors at the dawn of technology.’

The team now hopes that researchers at other archaeological sites will want to apply similar mechanical tests and techniques to help understand the behaviour of Stone Age populations.



Contacts and sources:
Gary Hughes
University of Kent

Global Warming 14 Million Years Ago Saw Temperatures Similar to 2100 Projections

Cardiff University scientists have shed new light on the Earth’s climate behaviour during the last known period of global warming over 14 million years ago.

During this period, known as the middle Miocene Climate Optimum, global temperatures were as much as 3 to 4 degrees warmer than today’s average temperatures, similar to estimates for 2100. The position of the continents were similar to today and the seas were flourishing with life.

Marine microfossil, foraminifera
Image of marine microfossil called foraminifera
Credit: Cardiff University


This period, which occurred between 15 and 17 million years ago, has puzzled geologists for decades as they have tried to explain the initial cause of the global warming and the environmental conditions that existed on Earth afterwards.

It is already known that this period of global warming was accompanied by massive volcanic eruptions which covered most of the modern-day Pacific Northwest in the USA, called the Columbia River flood basalts.

Around the same time a significant oil-rich layer of rock, known as the Monterey Formation, was created along the coastline of California as a result of the burial of carbon-rich marine life.

Up until now scientists have struggled to piece together the puzzle and come up with a viable explanation for the origin of the warmth and the link between the volcanic eruptions and the increased amounts of carbon burial.

Prof Carrie Lear, the senior scientist on the study and based at Cardiff University’s School of Earth and Ocean Sciences, said: “Our planet has been warm before. We can use ancient fossils to help understand how the climate system works during these times.”

In their study, published today in the journal Nature Communications, the team used the chemistry of marine fossils taken from long sediment cores from the Pacific, Atlantic and Indian oceans to fingerprint the temperature and carbon levels of the seawater in which the ancient creatures once lived during the middle Miocene Climate Optimum.

Their results showed that the massive volcanic eruptions of the Columbia River flood basalts released CO2 into the atmosphere and triggered a decline in ocean pH. With global temperatures rising as a consequence of this, sea-levels also rose, flooding large areas of the continents. This created the ideal conditions to bury large amounts of carbon from the accumulations of marine organisms in sediments, and to transfer volcanic carbon from the atmosphere to the ocean over tens of thousands of years.

“The elevated marine productivity and carbon burial helped to remove some of the carbon dioxide from the volcanoes and acted as a negative feedback, mitigating some, but not all, of the climatic effects associated with the outpouring of volcanic CO2,” said lead author of the study Dr Sindia Sosdian from Cardiff University’s School of Earth and Ocean Sciences.

Past large episodes of volcanism throughout Earth’s history have been linked to mass extinctions and widespread oxygen depletion in the oceans; however, there was no such occurrence in the middle Miocene Climate Optimum.

Co-author of the study Dr Tali Babila from the School of Ocean and Earth Sciences at the Univesity of Southampton added: “During the Miocene Climatic Optimum the response of the oceans and climate was remarkably similar to other massive volcanic eruptions in the geological record. The presence of the Antarctic ice sheet and the relatively slow release of carbon however minimised the magnitude of environmental change and the associated consequences on marine life during this event.”

“Thanks to our findings we now have a very clear picture of what was going on over 14 million years ago and this will change the way that scientists look at this period of global warming,” continued Dr Sosdian.

“We know that our current climate is warming much faster than the Miocene Climatic Optimum so we won’t be able to rely on these slow natural feedbacks to counteract global warming. But this research is still important because it helps us understand how our planet works when it is in a warm mode.”

This collaborative study involves Cardiff University (UK), the University of Southampton (UK), and St. Andrews University (UK) and is part of an research project funded by the National Environmental Research Council (NERC).



Contacts and sources:
Dr Sindia Sosdian, Professor Carrie Lear
Cardiff University