More Like this

1. FOCUSING ON INDIVIDUAL WOODEN BUILDINGS REVEALS CHANGES IN THE LATE TO TERMINAL CLASSIC ECONOMY AT THE PAYNES CREEK SALT WORKS

   McKillop, Heather; Sills, E Cory (June 2023, Research Reports in Belizean Archaeology)

   Preservation of wooden building posts in red mangrove (Rhizophora mangle) peat below the sea floor at the Paynes Creek Salt Works in southern Belize provides a rare opportunity to study pole and thatch buildings that were likely the dominant construction in the Maya area in prehistory. In 2020 and 2021, when field research at the salt works was not possible due to the covid pandemic, individual wooden buildings at two of the largest sites, Ek Way Nal and Ta’ab Nuk Na, were radiocarbon dated. The dates indicate that the buildings were constructed at different times. Associated artifacts reveal both residences and salt kitchens at both sites and that production began earlier at Ta’ab Nuk Na and ended later at Ek Way Nal. Identification of tree species used in building construction at Ek Way Nal indicates the salt workers selected useful trees and did not overuse the environment. 

   more » « less
2. Household salt production by the Late Classic Maya: underwater excavations at Ta'ab Nuk Na

   https://doi.org/10.15184/aqy.2022.106  

   McKillop, Heather; Sills, E Cory (October 2022, Antiquity)

   Salt is an essential commodity; archaeological remains around the world attest to the importance of its production, exchange and consumption. Often located in coastal locations, many production sites were submerged by rising seas, including the Paynes Creek Salt Works on the southern Belize coast. Survey and excavation of these sites has identified ‘kitchens’ for brine boiling, as well as Terminal Classic residential structures at Ek Way Nal. The authors report the discovery of an earlier residential building alongside salt kitchens at the nearby site of Ta'ab Nuk Na. This finding indicates that surplus household production began during the Late Classic, when demand for salt from inland cities was at its peak. 

   more » « less
3. Human–environment interactions at Ta'ab Nuk Na, a submerged Maya salt works site in Belize

   https://doi.org/10.1017/S0956536123000196  

   Foster, Cheryl M; McKillop, Heather; Sills, E Cory (August 2023, Ancient Mesoamerica)

   Abstract Sea-level rise and settlement are investigated at Ta'ab Nuk Na, an ancient Maya salt works in Belize, by examining samples from wooden posts and marine sediment. The samples included Post 145 of Building B and the Nunavut beam, along with marine sediment columns cut from beside both wooden posts. The sediment columns were sampled at 2 cm intervals. Loss-on ignition confirmed the presence of organic material. Identifying the organic content involved removing nonorganic material from the sediment and sorting the organic material under magnification. This procedure established that most of the organic material was red mangrove (Rhizophora mangle). Red mangroves tolerate salt water, but under conditions of sea-level rise, the plants grow vertically to keep their leaves above water. Sediment, leaves, and detritus trapped in the prop roots form mangrove peat, which serves as a proxy for sea-level rise. AMS dating of fine red mangrove roots determined that the local sea levels rose at Ta'ab Nuk Na throughout the Late Classic period and continued into the Postclassic period. Radiocarbon dates obtained from the wood-post samples yielded Late Classic–period dates. Comparing the radiocarbon dates from the wooden posts and the sediment core samples determined that the site was abandoned before the rising seas flooded the area. Evidently, sea-level rise did not play a role in site abandonment. 

   more » « less
4. Human-environment interactions at Ta’ab Nuk Na, a submerged Maya salt works site in Belize

   Foster, Cheryl M; McKillop, Heather; Sills, E Cory (August 2023, Ancient Mesoamerica)

   Sea-level rise and settlement are investigated at Ta'ab Nuk Na, an ancient Maya salt works in Belize, by examining samples from wooden posts and marine sediment. The samples included Post 145 of Building B and the Nunavut beam, along with marine sediment columns cut from beside both wooden posts. The sediment columns were sampled at 2 cm intervals. Loss-on ignition confirmed the presence of organic material. Identifying the organic content involved removing nonorganic material from the sediment and sorting the organic material under magnification. This procedure established that most of the organic material was red mangrove (Rhizophora mangle). Red mangroves tolerate salt water, but under conditions of sea-level rise, the plants grow vertically to keep their leaves above water. Sediment, leaves, and detritus trapped in the prop roots form mangrove peat, which serves as a proxy for sea-level rise. AMS dating of fine red mangrove roots determined that the local sea levels rose at Ta'ab Nuk Na throughout the Late Classic period and continued into the Postclassic period. Radiocarbon dates obtained from the wood-post samples yielded Late Classic–period dates. Comparing the radiocarbon dates from the wooden posts and the sediment core samples determined that the site was abandoned before the rising seas flooded the area. Evidently, sea-level rise did not play a role in site abandonment. 

   more » « less
5. High-Temperature Properties and Applications of Si-Based Polymer-Derived Ceramics: A Review

   https://doi.org/10.3390/ma14030614  

   Ren, Zhongkan; Mujib, Shakir Bin; Singh, Gurpreet (February 2021, Materials)

   null (Ed.)

   Ceramics derived from organic polymer precursors, which have exceptional mechanical and chemical properties that are stable up to temperatures slightly below 2000 °C, are referred to as polymer-derived ceramics (PDCs). These molecularly designed amorphous ceramics have the same high mechanical and chemical properties as conventional powder-based ceramics, but they also demonstrate improved oxidation resistance and creep resistance and low pyrolysis temperature. Since the early 1970s, PDCs have attracted widespread attention due to their unique microstructures, and the benefits of polymeric precursors for advanced manufacturing techniques. Depending on various doping elements, molecular configurations, and microstructures, PDCs may also be beneficial for electrochemical applications at elevated temperatures that exceed the applicability of other materials. However, the microstructural evolution, or the conversion, segregation, and decomposition of amorphous nanodomain structures, decreases the reliability of PDC products at temperatures above 1400 °C. This review investigates structure-related properties of PDC products at elevated temperatures close to or higher than 1000 °C, including manufacturing production, and challenges of high-temperature PDCs. Analysis and future outlook of high-temperature structural and electrical applications, such as fibers, ceramic matrix composites (CMCs), microelectromechanical systems (MEMSs), and sensors, within high-temperature regimes are also discussed. 

   more » « less