Detecting time-averaging and spatial mixing using oxygen isotope variation: a case study

摘要: Abstract In principle, bivalve mollusks living at the same time and in place will experience temperature salinity regimes have identical annual oxygen isotope ( δ 18 O) profiles. Bivalve different times or places are more likely to O Thus, differences profiles can be used detect temporal spatial mixing. We devised eight metrics quantitatively compare sclerochronologically calibrated from shells: difference maximum value, minimum amplitude, number of non-contemporaneous isotopic enrichment events (NNEE), average fortnightly (AD), standard deviation (SDD), (MaxD) fortnights separating values. These vary among northern Gulf California shells four categories: (1) place; (2) (3) (4) place. Different time/different comparisons include live-collected with alive during Colorado River flow a Pleistocene interglacial deposit. The time/same comparison has most similar metric values, whereas usually least similar. Between-shell reveal mixing that would undetectable radiocarbon amino-acid racemization dating. Application technique Holocene deposit life position reveals bivalves were times, despite indistinguishable ages. Two adjacent but disarticulated appear both temporally spatially mixed. method any shell material unaffected by diagenesis, regardless age specimens.