The dating game
Posted on homepage: 21 August 2013 (GMT+10)
In western New South Wales, Australia, part of a semi-arid desert has been set aside as a World Heritage area.1 This may seem curious for such an inhospitable region. But there is a good reason. Evolutionists believe that the site represents an outstanding example of the major stages in man’s evolutionary history.
It all centres on the discovery of human remains in sand dunes surrounding ancient Lake Mungo—now a dry, flat plain, vegetated by scraggly salt-tolerant bushes and grasses.
The first major find, in 1969, was of crushed and burnt skeletal fragments, interpreted to be of a female called Lake Mungo 1, or more affectionately Mungo Woman.2,3 What made the find significant was the assigned date. Carbon-14 dating (see Dating methods) on bone apatite (the hard bone material) yielded an age of 19,000 years and on collagen (soft tissue) gave 24,700 years.3 This excited the archaeologists, because that date made their find the oldest human burial in Australia.
But carbon-14 dating on nearby charcoal produced an ‘age’ up to 26,500 years. This meant that the skeleton, buried slightly lower than the charcoal, must have been older. Not surprisingly, the older charcoal age was considered to be the ‘most reliable’ estimate3 and launched Mungo Woman to national and international fame. Jane Balme, of the Centre for Archaeology at the University of Western Australia, put it succinctly, ‘There’s a general perception that there is a competition to get the oldest date and there’s kudos in it.’4
Certainly, there was kudos in this date. At 26,000 years, Mungo Woman was nearly twice as old as the previous oldest date for Aboriginal settlement of Australia, and possibly the earliest human cremation in the world.
Then, in 1974, Bowler and Thorne found a skeleton sprinkled with powdered red ochre in a grave only 450 metres away.5 This one was well preserved and similar to the skeletons of modern Aborigines. Because the new skeleton, Lake Mungo 3, was found in the same sand bed (technically the same stratigraphic horizon), ‘he’ was assigned the same age as Mungo Woman. Thus Mungo Man became famous too—one of the world’s earliest ritual burials (even though the sex of the individual is still in dispute6).
The situation became even more exciting when a different dating method (thermoluminescence, see Dating methods) was used. In 1998, Bowler reported that sand from the Mungo 3 site gave an age of some 42,000 years.5,7 Being older than the carbon-14 dates, Mungo Man acquired a new stature on the world evolution scene. So, the earlier ‘reliable’ carbon-14 ages were abandoned in favour of the thermoluminescence ones.
Evolution and the first Australians1
Darwin considered the Australian Aborigines as primitive and not much evolved from the ‘anthropoid apes’. He anticipated that the ‘wilder races’ would become extinct because survival of the fittest meant they would be superseded by the evolutionarily-advanced ‘civilised’ races.2 An evolutionary view of human origins underlies the World Heritage listing of the Lake Mungo site. Such a view was not good for the first Australians. Many atrocities were perpetrated on Aboriginal communities because of these evolutionary beliefs.
Incredibly, in the 1800s, it was not uncommon for Aboriginal people to be hunted and shot as specimens for science.3 Their remains were sent to Europe to illustrate evolution displays in museums. Only now are these remains being returned to their communities.4
But the Bible records our true human history. The first Aboriginal settlers to Australia were descended from people as intelligent and inventive as any other culture at that time. Like everyone else, they were descended from Noah, who built and managed the Ark, and from a people who developed an advanced civilization around the Tower of Babel.5
The Aborigines of Australia lost some of their technological know-how—it can happen in a generation if parents do not pass it on to their children. (Perhaps it was because of isolation and the pressure to cope with a worsening climate as the continent dried out after the Ice Age.) They, like other peoples, are made ‘in the image of God’ (Genesis 1:26).
References and notes
- For more information, see One Human Family.
- Darwin, C., The Descent of Man and Selection in Relation to Sex, 2nd ed., John Murray, London, p. 188, 1887.
- Wieland, C., Darwin’s bodysnatchers: new horrors, Creation 14(2):16–18, 1992.
- Aboriginal remains returned to Coorong tribe, ABC Canberra News, abc.net.au, 5 May 2003.
- For more information, see: McKeever, S. and Sarfati, J., Was Adam from Australia? The mystery of Mungo Man, 17 January 2001, updated 20 February 2003.
Then, in 1999, Thorne (not to be outdone) and other scientists from the Australian National University published a new comprehensive study on the age of Mungo Man. They used different samples of bone and sand and different dating methods—electron-spin resonance (ESR), optically-stimulated luminescence (OSL), thorium-uranium (Th/U) and protactinium-uranium (Pa/U). (Don’t worry about the big names. See Dating methods.) And the results from all the different methods agreed closely. Their conclusion? Mungo Man was 62,000 years old! Bowler and Magee described this 20,000-year stretch as ‘commendable in intent.’8
There was just one small problem. The new date meant that the history of Australian occupation would have to be rewritten and it also affected the ideas of human evolution in other parts of the world. And Australian archaeologists were still embarrassed by the Jinmium rock shelter fiasco, where a claimed age of 116,000 years was later reduced to 5,000 years.9
So, Bowler stubbornly refused to accept the new dates. In his protest to Journal of Human Evolution, he said ‘For this complex, laboratory-based dating to be successful, the data must be compatible with the external field evidence.’8 In other words, you don’t just accept a laboratory date without question. It’s not the last word on the age of something. You only accept the date if it agrees with what you already think it should be.
And that is what we have been saying all along.10 That is why we won’t accept any date that contradicts the eyewitness evidence of human history recorded in the Bible. Such contradictory dates can’t be right.
In short, the dates are wrong because they are based on wrong assumptions. For example, the carbon-14 method does not account for the disruption of the carbon balance during the Flood some 4,500 years ago.11 The uranium methods do not make the correct assumptions about the initial conditions of the samples or about the effects of changing environmental conditions through time. The luminescence dates have the same problem.
So, who are Mungo Man and Mungo Woman? Like us, they descended from Noah and his family (Genesis 10). After the Flood, and after the confusion of languages at the Tower of Babel (Genesis 11), their ancestors migrated to Australia. As the populations grew, they spread out over the continent. During the Ice Age, when rainfall was higher, Lake Mungo would have been a lush area to live in, teeming with wildlife.
- Carbon-14 dates are determined from the measured ratio of radioactive carbon-14 to normal carbon-12 (14C/12C). Used on samples which were once alive, such as wood or bone, the measured 14C/12C ratio is compared with the ratio in living things today. The date is calculated by assuming the change of 14C in the sample is due entirely to radioactive decay. It is also assumed that carbon has been in equilibrium on the earth for hundreds of thousands of years.
Wrong dates are usually caused by assuming a wrong initial 14C/12C ratio, contamination or leaching. Samples from before the Flood, or from the early post-Flood period, give ages that are too old by tens of thousands of years. This is because the Flood buried lots of 12C-rich plants and animals. This would result in a lower 14C/12C ratio, which is wrongly interpreted as great age.
- Thermoluminescence (TL) dates are obtained from individual grains of common minerals such as quartz. When such grains are heated, they emit light, and this is related to the radiation ‘stored’ in the crystal structure. It is assumed that the radiation was slowly absorbed from the environment, building up from zero at a certain time in the past (perhaps when the grain was last exposed to sunlight). A date is calculated by measuring the light emitted from the mineral grain when it is heated, and measuring the radiation in the environment where the grain was found.
Unfortunately, there are many unknowns and many assumptions need to be made, including the amount of radiation ‘stored’ in the mineral at a certain time in the past, that the change in radiation has only been affected by the radiation in the environment, that the radiation in the environment has remained constant, and that the sensitivity of the crystal to radiation has not changed. All these factors can be affected by water, heat, sunlight, the accumulation or leaching of minerals in the environment, and many other causes.
- Optically-stimulated luminescence (OSL) dates are based on exactly the same principle as TL. But instead of heating the grain, it is exposed to light to make it emit its ‘stored’ radiation. The calculated date is based on the same assumptions, and affected by the same uncertainties, as for TL.
- Electron-spin resonance (ESR) dates are based on the same principles as TL and OSL. However, the ‘stored’ radiation in the sample is measured by exposing it to gamma radiation and measuring the radiation emitted. The measuring technique does not destroy the ‘stored’ radiation (as does TL and OSL), so the measurement can be repeated on the same sample. The calculated date is based on the same assumptions, and affected by the same uncertainties, as for TL and OSL.
- Thorium-uranium (Th/U) dates are based on measuring the isotopes of uranium and thorium in a sample. It is known that uranium-238 decays radioactively to form thorium-230 (through a number of steps, including through uranium-234). The dating calculation assumes that the thorium and uranium in the sample are related to each other by radioactive decay. Furthermore, before a date can be calculated, the initial ratios of 230Th/238U and 234U/238U need to be assumed, and it is also assumed that there has been no gain or loss of uranium or thorium to/from the environment—i.e., that the system is ‘closed’. However, the bone and soil must have been ‘open’ to allow these elements to enter and accumulate.
- Protactinium-uranium (Pa/U) dates are based on similar principles as Th/U dating, but use uranium-235 and protactinium-231 instead. The isotope 235U decays radioactively to form 231Pa. Again, it is assumed that the isotopes in the sample are related to each other by radioactive decay. Also, the initial ratio of 231Pa/235U has to be assumed, and it is assumed that there has been no gain or loss of uranium or protactinium to/from the environment—i.e., that the system is ‘closed’. Again, any bone sample containing uranium must have been ‘open’ to allow it to accumulate in the first place.
- Details about dating methods may be obtained from such sources as: Smart, P.L. and Frances, P.D. (Eds.), Quaternary Dating Methods—A User’s Guide, Quaternary Research Association, Technical Guide No. 4, Cambridge, 1991, or Faure, G., Principles of Isotope Geology, 2nd edition, John Wiley & Sons, New York, USA, 1986.
- Willandra Lakes Region: inscribed 1981, ea.gov.au, 4 August 2003. Return to text.
- Fannin, P., Mungo jumbo, The Age, p. 5, Saturday, 13 January 2001. Return to text.
- Brown, P., Lake Mungo 1, une.edu.au, 21 February 2003. Return to text.
- In the beginning, The Bulletin, pp. 26–33, 24 June 2003. Return to text.
- Thorne, A., et al., Australia’s oldest human remains: age of the Lake Mungo 3 skeleton, J. Hum. Evol. 36:591–612, 1999. Return to text.
- Brown, P., Australian Pleistocene variation and the sex of Lake Mungo 3, J. Hum. Evol. 38:743–749, 1999. Return to text.
- Bowler, J.M., et al., New ages for human occupation and climatic change at Lake Mungo, Australia, Nature 42(6925):837–840, 2003. Return to text.
- Bowler, J.M. and Magee, J.W., Redating Australia’s oldest human remains: a sceptic’s view, J. Hum. Evol. 38:719–726, 2000. Return to text.
- Brown, P., The first Australians: the debate continues, Australasian Science 21(4):28–31, 2000. Return to text.
- Walker, T., The way it really is: little known facts about radiometric dating, Creation 24(4):20–23, 2002. Return to text.
- Batten, D. (Ed.), The Creation Answers Book, Creation Ministries International, Brisbane, Australia, Chapter 4, 2006. Return to text.