Ask anybody today what the fundamental requirements of life are, and they will tell you….food, shelter, lighting, warmth, their iphone…
Ask anybody in prehistory what the fundamental requirements of life are, and they may tell you….food, shelter, lighting, warmth…
And for most of this, until recently, that meant fire.
Fire to protect, Fire to cook, Fire to see, Fire to sustain. And at times, it was Fire to communicate.
Scientists and archaeologists have today released in the Proceedings of the National Academy of Sciences that humans, or rather hominids, our direct ancestors, were able to harness and control fire approximately 600,000 years before previously accepted dates.
New evidence is pointing to a new date of 1 million years ago (1Ma).
The article, here, goes on that it has generally been accepted that Homo erectus was cooking food at approximately 1.9Ma, however there has been little archaeological evidence to support the controlled use of fires to prepare food prior to consumption at this date. The earliest confirmed site has been known at Qesem Cave in Israel, and dated at 0.4Ma, 400,000 years ago.
In the ongoing academic debate of whose site is oldest, earliest and shows best evidence of, or similarity to, modern humans, Francesco Bernaa, Paul Goldberga, Liora Kolska Horwitz, James Brink, Sharon Holt, Marion Bamford,
and Michael Chazang have offered up the latest method to better understand the inhabitants of the Early Acheulian (or Early Stone Age) period at Wonderwerk Cave in South Africa, and their manipulation of fire.
There have been other claims of controlled fires in the early Acheulian period in the recent past such as at Koobi Fora, Gadeb, Chesowanja in East Africa, and Gesher Benot Ya’akov in Israel, but todays authors suggest that the previous studies lack context that can be gained through morphological studies.
Using Fourier Transform Infra-red Micro-spectroscopy (mFTIR) and Micromorphological analysis the researchers have been able to observe and characterise sediments at the microscopic level, that until recently has not been possible.
The result being that the presence and nature of burnt bone and plant ash in the cave site of Wonderwerk, translated as Miracle Cave, has enabled this staggering shift back in time.
The control and manipulation of fire is considered a major evolutionary step for humans, before which it is thought we used fire generated through naturally occurring events, such as lightening, scrub fires, and natural combustion due to chemical reaction, such as with the self ignition of guamo ( bird or bat droppings).
Wonderwerk Cave in South Africa, seen above, is a natural solution cavity which in 2008 was celebrated as the earliest site in the world to reveal evidence of human occupation in a cave, dated to 2 million years by Professor Michael Chazin, see here. Stone tools found at the base of the caves archaeological strata supported this and were attributed to the Acheulian period (or early Stone Age), approximately 1.7-0.8 Ma.
The cave was extensively excavated by Peter Beaumont of McGregor Museum from 1978-1993, and rock art has been recorded at the entrance.
Inside Wonderwerk Cave. Left, Credit: Image of Wonderwerk Cave. (Image courtesy of M. Chazan.)
In the article released today, the researchers claim that the combined use of mFTIR and analysis of the micromorphology has revealed deposits from Stratum 10 that contain:
* charred bone heated to at least 500 degrees C, and
* angular/sharp edged, complete and incomplete bone that suggest deposits have not moved far
* exceptionally preserved plant remains suggest deposits have not moved far, and
* charring or burning is most likely to have been caused by local combustion
Stratum 10 samples were studied macroscopically as well as microscopically, showing that:
* in one area of the cave the frequency of burnt bone reached 80%,
* FTIR (Fourier Transform Infra-red spectroscopy) revealed burning occurred between 400 and 700 degrees C,
* artefact analysis supports controlled heating in one area of the cave with banded iron stone artefacts and manuports displaying pot lid fractures (an often thermally induced fracture which creates a shallow bowl shaped depression in the parent rock which occurs at temperatures in excess of 500 degrees C),
* heat affected clays that support localised in situ burning over a wide area within the cave
The Layers of Strata Inside Wonderwerk Cave. Below, Credit: Image of Wonderwerk Cave. (Image courtesy of M. Chazan.)
In essence the researchers appear to demonstrate undisturbed archaeological contexts and deposits across a widespread area within the cave that contain evidence of ongoing, or repeated cycles of burning or fire making…but with no evidence of a fire surround, hearth structure or pit in which to contain the fire.
What’s to say that Stratum was not blown in by a mighty wind, washed in by a flood or heavy rain, or the product of an ancient ground disturbance which has affected the dates?
Two reasons, from what the article says:
- 1. The micromorphological evidence, and the way the dateable materials and artefacts were laid down in the earth,
- 2. Crucially, the security of the layers seem to be intact, with Stratum 10 sandwiched between earlier and later Acheulian deposits that display no signs of heating, dispelling a possible counter argument for a later episode of combustion whose heat could have modified this Stratum.
Good Science Practise?
The article released today also highlights the importance of cross examining archaeological evidence, by more than one method of analysis, when attempting to establish dates that require microscopic and molecular level technologies.
This includes using analytical techniques such as mFTIR, Thermoluminescence, Potassium-Argon (K-Ar) dating, and combining it with, for example:
- Examination of the stratigraphy at the microscopic scale,
- Establishing if the deposit is natural or anthropogenic in origin (the product of or affect by humans),
- Establishing the past environment of the fire
- Establishing the security of a site or deposit (that is to establish if the deposit has been contaminated or disturbed in some way through natural processes, chemical change and biological influence) is also considered by the authors as crucial, in setting the dates apart from other sites that have generated earlier dates than 0.4ma through other analytical methods.
Whatever the lesson is to be learnt regarding good scientific practise, the results of this latest study has big, and potentially exciting implications for the future. By knocking 600,000 years off the closest confirmed date for cave dwelling fire users, It both opens up the race to re-examine past sites using different techniques, and holds the door wide open for future dating analysis.