Textural and geochemical features of freshwater microbialites from Laguna Bacalar, Quintana Roo, Mexico

Microbialites provide some of the oldest direct evidence of life on Earth. They reached their peak during the Proterozoic and declined afterward. Their decline has been attributed to grazing and/or burrowing by metazoans, to changes in ocean chemistry, or to competition with other calcifying organisms. The freshwater microbialites at Laguna Bacalar (Mexico) provide an opportunity to better understand microbialite growth in terms of interaction between grazing organisms versus calcium carbonate precipitation. The Laguna Bacalar microbialites are described in terms of their distinct mesostructures. Stromatolites display internal lamination, attributed to the precipitation of calcite and the upward migration of cyanobacteria during periods of low sedimentation. Thrombolitic stromatolites show internal lamination in addition to internal clotting. The clotting is seen as a result of binding and/or trapping of micritic peloids by cyanobacteria and attributed to periods of high sedimentation. The carbonates in both microbialites had similar C- and O-stable–isotopic signatures, both enriched in ^(13)C relative to bivalves, suggesting photosynthetic CO_2 uptake was the trigger for carbonate precipitation. This implies that the rate of microbialite growth is largely a function of ambient carbonate saturation state, while the texture is especially dependent on accretion rates and sediment deposition on their surface. Importantly, the coexistence with grazing animals suggests no significant inhibition on microbialite growth, thereby calling into question the decline of microbialite as a result of metazoan evolution. Varying sedimentation rates are likely important in controlling the distribution of thrombolite–stromatolite packages in the geological record, given the importance of this factor at Bacalar

The effect of diet and sociopolitical change on physiological stress and behavior in late Roman‐Early Byzantine (300–700 AD) and Islamic (902–1,235 AD) populations from Ibiza, Spain

Objectives This study evaluated chronological changes in physiological stress and levels of habitual loading of Ibizan populations from the Late Roman-Early Byzantine to the Islamic period (300-1235 AD) using measures of body size and bone cross-sectional properties. It also explored the effect of diet, modeled using stable isotopes, on physiological stress levels and behavior. Materials and Methods American Journal of Physical Anthropology, Volume 172, Issue 2, June 2020 pp. 189-213 DOI:10.1002/ajpa.24062 Published by Wiley. This is the Author Accepted Manuscript issued with: Creative Commons Attribution Non-Commercial License (CC:BY:NC 4.0). The final published version (version of record) is available online at DOI:10.1002/ajpa.24062. Please refer to any applicable publisher terms of use. 2 The sample comprised individuals from three archaeological populations: Urban Late Roman- Early Byzantine (LREB) (300-700 AD), Medieval Urban Islamic (902-1235 AD), and Rural Islamic. Bone lengths, femoral head dimensions, and diaphyseal products and circumferences were compared to assess differences in body size and habitual loading in 222 adult individuals. Ordinary least squares regression evaluated the correlations between these measures and carbon (δ13C) and nitrogen (δ15N) stable isotope ratios in 115 individuals for whom both isotope values and osteological measures are available. Results The Rural Islamic group had shorter stature and reduced lower limb cross-sectional properties compared to the two urban groups. In both LREB and Islamic groups, body mass and femur length was positively correlated with δ13C values, and δ15N shows a positive correlation with left humerus shape in the LREB Urban sample. Conclusions The low stature and cross-sectional properties of the Rural Islamic group are most likely an indicator of greater physiological stress, potentially due to poorer diet. Positive correlations between measures of body size and δ13C values further suggest that greater access to C4 resources improved diet quality. Alternatively, this relationship could indicate greater body size among migrants from areas where individuals consumed more C4 resources

La necrópolis Fenicia de Tiro-Al Bass en el contexto funerario fenicio oriental

La necrópolis de Tiro-Al Bass combina una serie de elementos ya observados en cementerios fenicios conocidos hasta el momento. El cementerio de Al Bass estaba situado en una zona alejada del asentamento urbano. La incineración era la única práctica funerario que se empleaba en la época fenicia en Tiro-Al Bass. Una vez quemados los restos de los difuntos, éstos eran depositados en urnas cerámicas. Dichas urnas, colocadas solas o en parejas, se enterraban en fosas excavadas en arena que eran macadas en superficia por estelas de piedra

Cypriot black-on-red ware: towards a characterization

Chemical analysis of Early Iron Age sherds from Cyprus and the Levant using atomic absorption spectrometry shows that Black-on-Red ware was manufactured only in Cyprus. Two types of fabric are isolated, calcareous and non-calcareous, and their technological significance discussed. The presence of trade links between the Cypriot sites of Kition and Amathus and sites in the Levant is suggested

An Interdisciplinary Methodology for the Characterization and Visualization of the Heritage of Roadway Corridors

Roads, particularly since the advent of motorized traffic, have hugely impacted contemporary landscapes. Although their significance was noted in the 1980s, specific roadway-heritage studies are scarce. Research in different disciplines has identified certain features of roads, but an integrated approach to roadway heritage or a consensus on what this constitutes are lacking. This article proposes an interdisciplinary methodology to assess roadway heritage. Roadways are interpreted within the framework of semantic openness that currently characterizes heritage studies, territory being the basic element of interpretation. Rather than a fragmented approach to conservation, the research defines integrated heritage configurations where natural, cultural, and historical features combine to produce a cohesive form of heritage. GIS (Geographical information systems) technology is used with an online database to assess the complexity of roadway heritage. ICT (Information and communications technology) strategies to raise public awareness are outlined. The methodology is applied to assess the historical N-340 Mediterranean roadway corridor in Spain