Our results demonstrate that Australia’s ancient and diverse geology culminates in a wider range in strontium isotopes than found in overseas studies. One of many new maps: Cape York strontium isotope results can be used to match human values to environmental signals in soil, plants and water. These maps were developed and created in close consultation with an Aboriginal advisory committee representing several Cape York Aboriginal communities.
#Sr element come from series
We sampled strontium isotopes throughout Cape York to build a series of maps that can show where people may have grown up. A new look at Far North Queenslandīefore strontium isotopes in human teeth can be used to determine their place of origin we must first know how the element in the landscape changes. One Elder from the advisory committee set up for this project, Gudjugudju, put it succinctly when he said that our ancestors carry the signature of their country in their bones and their teeth. Our bodies become an isotope record of where we have been and what we have eaten. So for people it’s not simply a case of “you are what you eat”, but also “you are where you ate”.
When rocks break down, these isotopes end up in soil and water, where they are taken up by plants, animals and humans. In particular, the amount of ⁸⁶Sr and ⁸⁷Sr in rock varies depending on the age of the rock and when it formed.īut strontium doesn’t just stay in rocks. Although these isotopes are stable, their natural abundance changes. The element strontium (chemical symbol, Sr) has an atomic number of 38 and four forms known as isotopes, ⁸⁴Sr, ⁸⁶Sr, ⁸⁷Sr and ⁸⁸Sr. We use strontium isotopes to help with resolving the issue of provenance: the place where people belong. Bones are also useful as they help provide information about the burial site. This makes it a suitable material to establish where a person was originally from. Tooth enamel is the hardest substance in the human body and can hold evidence of the region where a person lived as a child. The strontium-based process involves measuring a robust geochemical signature, not a biological one subject to decomposition. Using the isotope chemistry of tooth enamel and bone we can bypass these issues of preservation. This makes the recovery of biological material for DNA analyses difficult and in some cases not at all possible. Australia’s harsh environmental conditions lead to a poor state of preservation in many remains. In a complementary project focusing on DNA, research has shown that genetic material can be used to help locate Aboriginal populations.īut the recovery of ancient DNA from many ancestral remains in Australia continues to prove challenging. Here in Australia, the strontium technique has had some use in a few cases, but in general is underutilised. Strontium isotopes in Otzi’s teeth helped scientists determine where he was born in northern Italy, which added to our understanding of the mobility of ancient European populations during the Chalcolithic period – the Copper Age from about 3500BCE to 2300BCE. Perhaps the most famous study involved the 5,000-year-old ice man Otzi who was found in the European Alps. These have helped in answering questions that relate to the behaviour of past populations. Strontium, named after Strontian, a small town in western Scotland, is described as a soft, silvery metal that burns in air and reacts with water.įor decades the ratio of two forms of strontium (the isotopes ⁸⁷Sr/⁸⁶Sr) have been measured in archaeological and palaeontological material. Strontium is an element in all rock and is transferred into body tissues. Our work uses the element strontium to determine specifically where somebody grew up. Our study, published today in the journal GeoArchaeology, aims to tackle the issue of repatriating such remains. What teeth can tell about the lives and environments of ancient humans and Neanderthals One estimate is that up to 25% of Aboriginal remains held in Australian institutions have no details of where they were taken from. The challenge is knowing where to return them.
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