17th April 2010, 11:21 PM
(This post was last modified: 17th April 2010, 11:24 PM by GnomeKing.)
"Is it possible that volcanic activity at different times in the past could affect this analysis i.e we might be getting 'false' readings based on the origins of isotopes released through volcanic activity rather than the geographic location of the person" ?
unlikely due to to
a)rapid dilution in the environment soon after volcanic ejecta deposited (especially if not close to source) and need for high residence time (chemically and in hydrological systems) to significantly affect organic hard tissue
b)pre-existing elemental distributions - areas of high volcanic activity might leave elemental/isotopic signitures in 'local' populations - but this would still be 'distinct' geographically - not sure about pyroclastic istope production as source of long lived(ie archaeologically detecable) isotopes distinct from other potential sources (equifinality) - would guess that high energy conditions allows for higher proportions of 'unstable' compounds and isotopes, and therefore not amenable to archaeological detection - however short lived (days to months) isotopes are successfully used to trace present day 'pollution' and hydrological/meteorological systems...
Isolating signature of single volcanic eruption in tooth? - no
Identifying repeated inputs of pyroclasticly generated material ingested material in hard organic tissue? - perhaps possible, if population close to repeated source... - however, its unlikely for contemporary volcanic production to overwrite signatures of basal geological and dominant meteorological conditions - even then weak traces with multiple possible sources will always be subject to equifinality problems - - given that most populations can not be considered as 'close' to contemporary volcanic activity, it must be assumed that dominant local hydrological-geological still pertain - populations living close to contemporary surface volcanism are very likely to be also sitting on top of volcanic substrates, with concomitant effect on biological uptake...thus, 'normal' problems of drinking water composition identification and 'normal' problems of isotope+elemental sourcing apply...
unlikely due to to
a)rapid dilution in the environment soon after volcanic ejecta deposited (especially if not close to source) and need for high residence time (chemically and in hydrological systems) to significantly affect organic hard tissue
b)pre-existing elemental distributions - areas of high volcanic activity might leave elemental/isotopic signitures in 'local' populations - but this would still be 'distinct' geographically - not sure about pyroclastic istope production as source of long lived(ie archaeologically detecable) isotopes distinct from other potential sources (equifinality) - would guess that high energy conditions allows for higher proportions of 'unstable' compounds and isotopes, and therefore not amenable to archaeological detection - however short lived (days to months) isotopes are successfully used to trace present day 'pollution' and hydrological/meteorological systems...
Isolating signature of single volcanic eruption in tooth? - no
Identifying repeated inputs of pyroclasticly generated material ingested material in hard organic tissue? - perhaps possible, if population close to repeated source... - however, its unlikely for contemporary volcanic production to overwrite signatures of basal geological and dominant meteorological conditions - even then weak traces with multiple possible sources will always be subject to equifinality problems - - given that most populations can not be considered as 'close' to contemporary volcanic activity, it must be assumed that dominant local hydrological-geological still pertain - populations living close to contemporary surface volcanism are very likely to be also sitting on top of volcanic substrates, with concomitant effect on biological uptake...thus, 'normal' problems of drinking water composition identification and 'normal' problems of isotope+elemental sourcing apply...