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An interdisciplinary approach to Iron Age Mediterranean chronology through combined archaeological and .sup.14C-radiometric evidence from Sidon, Lebanon
The construction of the Iron Age Mediterranean chronology began in the Levant based on historical evidence and has been additionally supported in recent decades by means of radiocarbon analysis, although with variable precision and ratification. It is only in recent years that new evidence in the Aegean and the western Mediterranean has opened discussion towards its further acceptance as an authoritative i.e. highly reliable, and widely applicable historiographic network. Altogether, the Mediterranean Iron Age chronology has only undergone minor changes during the last hundred years. The Phoenician metropolis of Sidon in southern Lebanon now provides a new, large and robust dataset obtained through a combination of archaeological and .sup.14 C-radiometric analysis of materials from stratified contexts that allow their statistical assessment. The appearance of substantial amounts of pottery of Greek, Cypriot and Egyptian origin together with Phoenician local wares in a long stratigraphy is a benefit for the synchronisation of regional pottery styles and allows wider geographic correlation of relative chronological systems. The close association of the archaeological data with a long series of AMS-.sup.14 C-dates on short-lived samples provides new evidence for the absolute dating of many of the regional pottery styles that are represented in the stratigraphy of Sidon, and contributes towards a considerable improvement of the Mediterranean chronology.
Journal Article
Revealing the Role of Coal Gangue-Biochar Composite for Removing SOsub.4sup.2− from Water: Adsorption Mechanisms and Application Effects
Sulfate ions are commonly found in water, but excessive concentrations of these ions can have detrimental effects on the aquatic environment. In this study, reed straw was chosen as the raw material for producing biochar, which was then pyrolyzed with coal gangue to create environmentally friendly adsorption materials. This innovative approach aims to combat the issue of elevated SO[sub.4] [sup.2−] concentrations in water while efficiently utilizing solid waste. The results showed that the adsorption process best fit the when the was pH 2 and the dosage was 8 g·L[sup.−1], and the adsorption capacity reached the maximum of 49.56 mg·g[sup.−1]. Via extensive characterization, kinetic studies, and isotherm experiments on the modified biochar, we determined that the mechanism of SO[sub.4] [sup.2−] adsorption primarily involves electrostatic adsorption, physical adsorption, and chemical adsorption. The toxicology experiments showed that the activity of antioxidant enzymes and the amount of malondialdehyde decreased, and the content of chlorophyll and soluble protein increased. These findings suggest that modified biochar can mitigate the harmful effects of SO[sub.4] [sup.2−] on reeds to a certain extent, ultimately promoting the growth of these plants.
Journal Article
Before civilization : the radiocarbon revolution and prehistoric Europe
This is a re-examination of the more glaring inconsistencies in the old theory of dating. Renfrew shows how the monuments of prehistoric Europe, like Stonehenge and the megalithic temples of ancient Malta, could have been built without recourse to help from the \"more civilized\" near East.
High-precision radiocarbon dating shows recent and rapid initial human colonization of East Polynesia
The 15 archipelagos of East Polynesia, including New Zealand, Hawaii, and Rapa Nui, were the last habitable places on earth colonized by prehistoric humans. The timing and pattern of this colonization event has been poorly resolved, with chronologies varying by >1000 y, precluding understanding of cultural change and ecological impacts on these pristine ecosystems. In a meta-analysis of 1,434 radiocarbon dates from the region, reliable short-lived samples reveal that the colonization of East Polynesia occurred in two distinct phases: earliest in the Society Islands A.D. ~1025-1120, four centuries later than previously assumed; then after 70-265 y, dispersal continued in one major pulse to all remaining islands A.D. ~1190-1290. We show that previously supported longer chronologies have relied upon radiocarbon-dated materials with large sources of error, making them unsuitable for precise dating of recent events. Our empirically based and dramatically shortened chronology for the colonization of East Polynesia resolves longstanding paradoxes and offers a robust explanation for the remarkable uniformity of East Polynesian culture, human biology, and language. Models of human colonization, ecological change and historical linguistics for the region now require substantial revision.
Journal Article
Radiocarbon-Based Chronology for Dynastic Egypt
The historical chronologies for dynastic Egypt are based on reign lengths inferred from written and archaeological evidence. These floating chronologies are linked to the absolute calendar by a few ancient astronomical observations, which remain a source of debate. We used 211 radiocarbon measurements made on samples from short-lived plants, together with a Bayesian model incorporating historical information on reign lengths, to produce a chronology for dynastic Egypt. A small offset (19 radiocarbon years older) in radiocarbon levels in the Nile Valley is probably a growing-season effect. Our radiocarbon data indicate that the New Kingdom started between 1570 and 1544 B.C.E., and the reign of Djoser in the Old Kingdom started between 2691 and 2625 B.C.E.; both cases are earlier than some previous historical estimates.
Journal Article
Seasonal dynamics and age of stemwood nonstructural carbohydrates in temperate forest trees
Nonstructural carbohydrate reserves support tree metabolism and growth when current photosynthates are insufficient, offering resilience in times of stress.
We monitored stemwood nonstructural carbohydrate (starch and sugars) concentrations of the dominant tree species at three sites in the northeastern United States. We estimated the mean age of the starch and sugars in a subset of trees using the radiocarbon (14C) bomb spike. With these data, we then tested different carbon (C) allocation schemes in a process-based model of forest C cycling.
We found that the nonstructural carbohydrates are both highly dynamic and about a decade old. Seasonal dynamics in starch (two to four times higher in the growing season, lower in the dormant season) mirrored those of sugars. Radiocarbon-based estimates indicated that the mean age of the starch and sugars in red maple (Acer rubrum) was 7–14 yr.
A two-pool (fast and slow cycling reserves) model structure gave reasonable estimates of the size and mean residence time of the total NSC pool, and greatly improved model predictions of interannual variability in woody biomass increment, compared with zero- or one-pool structures used in the majority of existing models. This highlights the importance of nonstructural carbohydrates in the context of forest ecosystem carbon cycling.
Journal Article
Distribution and mixing of old and new nonstructural carbon in two temperate trees
We know surprisingly little about whole‐tree nonstructural carbon (NSC; primarily sugars and starch) budgets. Even less well understood is the mixing between recent photosynthetic assimilates (new NSC) and previously stored reserves. And, NSC turnover times are poorly constrained. We characterized the distribution of NSC in the stemwood, branches, and roots of two temperate trees, and we used the continuous label offered by the radiocarbon (carbon‐14,¹⁴C) bomb spike to estimate the mean age of NSC in different tissues. NSC in branches and the outermost stemwood growth rings had the¹⁴C signature of the current growing season. However, NSC in older aboveground and belowground tissues was enriched in¹⁴C, indicating that it was produced from older assimilates. Radial patterns of¹⁴C in stemwood NSC showed strong mixing of NSC across the youngest growth rings, with limited ‘mixing in’ of younger NSC to older rings. Sugars in the outermost five growth rings, accounting for two‐thirds of the stemwood pool, had a mean age < 1 yr, whereas sugars in older growth rings had a mean age > 5 yr. Our results are thus consistent with a previously‐hypothesized two‐pool (‘fast’ and ‘slow’ cycling NSC) model structure. These pools appear to be physically distinct.
Journal Article