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Abstract ObjectivesBomb pulse (BP) radiocarbon (¹⁴C) dating methods are used by forensic anthropologists to estimate the year‐of‐death (YOD) of unidentified individuals. Method resolution and accuracy depend on establishing lag times, or the difference between a tissue's BP¹⁴C‐derived year and the YOD, of various tissue types from known deceased persons. Bone lag times span many years and are thought to increase with age as a function of slowing remodeling rates. However, remodeling rates for various skeletal elements, bone structures and phases are not well known. Materials and MethodsHere a simple method is used to estimate bone remodeling rates from a compilation of published cortical femur bone collagen BP¹⁴C measurements (n = 102). Linear regression models and nonparametric tests are used to detect changes in lag times and remodeling rates with increasing age‐at‐death. ResultsRemodeling rates and lag times of 3.5%/year and 29 years, respectively, are estimated from individuals aged 40–97 years. In contrast to previous work, the analysis yielded modest and negligible changes in remodeling rates and lag times with advancing age. Moreover, statistically significant differences in remodeling rates and lag times were not found between reported females and males. DiscussionImplications for the temporal contexts within an individual's lifetime of biogeochemical data in archaeology and forensic anthropology are discussed, warranting additional BP¹⁴C studies of known individuals and integration with histomorphometric analysis. 

Abstract The extinction of theParanthropus boiseiestimated to just before 1 Ma occurred when C₄grasslands dominated landscapes of the Eastern African Rift System (EARS).P. boiseihas been characterized as an herbivorous C₄specialist, and paradoxically, its demise coincided with habitats favorable to its dietary ecology. Here we report new pedogenic carbonate stable carbon (δ¹³C_PC) and oxygen (δ¹⁸O_PC) values (nodules = 53, analyses = 95) from an under-sampled interval (1.4–0.7 Ma) in the Turkana Basin (Kenya), one of the most fossiliferous locales ofP. boisei. We combined our new results with published δ¹³C_PCvalues from the EARS dated to 3–0 Ma, conducted time-series analysis of woody cover (ƒ_WC), and compared the EARS ƒ_WCtrends to regional and global paleo-environmental and -climatic datasets. Our results demonstrate that the long-term rise of C₄grasslands was punctuated by a transient but significant increase in C₃vegetation and warmer temperatures, coincident with the Mid-Pleistocene Transition (1.3–0.7 Ma) and implicating a short-term rise inpCO₂. The contraction of C₄grasslands escalated dietary competition amongst the abundant C₄-feeders, likely influencingP. boisei’s demise. 

Geoprofiling isotopic analyses provide investigative leads for unidentified human remains cases by determining possible regions of origin or excluding unlikely residences during life, which in turn can reduce the number of missing persons an investigator mustconsider. However, maceration methods involving heat, bleach, baking soda, and detergents have much potential to significantly change biogenic isotopic values in the structural carbonate phase of bone bioapatite. Here we test the impact of seven maceration methods on δ13C and δ18O values of bone carbonate (BC) of pig (Sus scrofa) ribs. Four of the seven maceration methods altered pig δ13CBC values with offsets ranging from 0.4‰ to 1.4‰; this amount of change would not severely impact human diet or geolocation interpretations. Five of the methods significantly decreased pig δ18OBC values by averages ranging between 1.0‰ and 2.6‰ likely due to the isotopic exchange between bone and heated water. As an illustrative exercise, we compared our study’s results to macerated rib δ13CBC and δ18OBC values of an identified New York City resident previously in the custody of the New York City Office of Chief Medical Examiner (NYC OCME). We suggest that maceration methods, especially those involving heated water, can potentially contribute to erroneous geolocation estimates garnered from rib δ18OBC values of unidentified individuals. 

Isotopic analyses of human remains augment the biological profile with geolocation and dietary information, furthering efforts to identify unknown individuals from a forensic context. Here we test the methodological resolution of geolocation (δ18O, 87Sr/86Sr) and dietary (δ13C, δ15N) isotopes of one identified individual who immigrated to New York City from St. Vincent and the Grenadines (SVG), Lesser Antilles. Isotope-based geolocation estimates did not identify the childhood residency on SVG, but did point to New York City as a possible residence during early adulthood. The individual’s C3-based diet did not significantly change from childhood to early adulthood, illustrating the maintenance of food traditions after the immigration event. This study illustrates that further development of tissue-specific isoscapes incorporating bioavailable foods, drinking water, and cultural traditions is warranted to refine methodological resolution of isotopic applications in forensic anthropology.