Mapping Human Movement using Stable Oxygen Isotopic Ratio Mass Spectrometry: Potential Application to Forensic Science Demonstrated by a Modern Horse-Human Study

Abstract

The utility of stable oxygen isotope analysis for demonstrating human migration has been developed and demonstrated on archaeological human populations. The application of this approach to tracking human movement has seldom been applied within forensic science. This paper gives results from a stable oxygen isotope assessment of extant modern human and horse enamel ␦ 18 O values recovered from tooth enamel. The human and horses were all constrained to known geographic locales for the period of tooth formation and compared to UK and global precipitation values for ␦ 18 O. It was found that human and horse values track one another and horse can be used with some confidence as a human proxy. UK values were constrained geographically and outlier values to the UK were identified between Iceland and the Sudan. For application within the realm of forensic science more research is required to understand the regionalized contribution of hydrology to a catchment and the potentially confounding contribution of mixed water sources. However, as a tool to track human movement within forensics there is clear utility.

The sinking of the Mary Rose warship: a medieval mystery solved?

“…3); these values are consistent with the modern range established by Bell et al (2006) and with the distribution of d w across the British Isles (Darling et al, 1996 Bell et al (2006). The values below this line are standard for the region, and correspond with average rainfall values as given in Darling (1999).…”

“…These individuals represent 33% of the sample group. If we were to shift the cut-off value slightly, to say, À4.5& (or 26.3& VSMOW), a value still consistent with the modern study (Bell et al, 2006) and taking into consideration the slightly cooler conditions at AD 1530, then this proportion increases to just over 60%. Whether 33 or 60%, given that our sample of skeletal material is randomly distributed across all decks, the results indicate that a sizable proportion of the crew were not natives of the British Isles during the period of their enamel formation, i.e.…”

“…The period AD 1500-1545 marks the beginning of a downward trend in temperature, which reached a minimum about AD 1695-1730 (Loehle, 2004) or, based on glacial records, extending to AD 1800 (Oerlemans, 2005). Therefore, based on what is known about past temperature shifts, we can confidently apply the upper boundary of the contemporary enamel oxygen data from Bell et al (2006) to the period of interest here.…”

“…The existence of species-level differences is indisputable, and in some cases the causes can be readily recognized, such as the strong influence of leaf water and hence relative humidity gradients on non-obligate drinking herbivores (Murphy et al, 2008 (Bell et al, 2006). Elsewhere, in North America, a recent study showed that oxygen and hydrogen isotope ratios in human hair reflect geographical latitudinal differences related to current d w distributions in that region (Ehleringer et al, 2008).…”

‘True British sailors’: a comment on the origin of the men of the Mary Rose

“…We map, approximately, the locations associated with their humans in Figure 2, along with isopleths of δ 18 O pptn (Darling, 2004 ranging from below about -5.0 ‰ in the extreme west to below -8.5 ‰ in the east (Darling, 2004). Consequently, we believe it is dangerous either to extrapolate even a broad equivalence of δ 18 O carb and δ 18 O pptn in humans, or to consider the data of Bell et al (2006) representative of the British Isles.…”