Evidence from Escalera al Cielo: Abandonment of a Terminal Classic Puuc Maya hill complex in Yucatán,Mexico

Abstract

Excavations at the hilltop site of Escalera al Cielo, located in the Puuc Maya region of Yucatán, Mexico, have uncovered evidence of a planned abandonment at the end of the Terminal Classic period (a.d. 800–950). Six buildings investigated among three residential groups contain rich floor assemblages similar to those known from only a few rapidly abandoned sites in the Maya area. Through an analysis of de facto refuse—most of which was recovered in locations of storage and provisional discard—and midden refuse, this paper illustrates how the assemblages represent an example of household-level abandonment with anticipated return. We also consider Escalera al Cielo in light of our present understanding of the political and environmental history of the Puuc region during the late 9th century a.d.     

Barite–pyrite mineralization of the Wiesbaden thermal spring system, Germany: a 500-kyr record of geochemical evolution

Barite–(pyrite) mineralizations from the thermal springs of Wiesbaden, Rhenish Massif, Germany, have been studied to place constraints on the geochemical evolution of the hydrothermal system in space and time. The thermal springs, characterized by high total dissolved solids (TDS) contents and predominance of NaCl, ascend from aquifers at 3–4 km depth and discharge at a temperature of 65–70°C. The barite–(pyrite) mineralization is found in upflow and discharge zones of the present‐day thermal springs as well as at elevations up to 50 m above the current water table. Hence, this mineralization style constitutes a continuous record of the hydrothermal activity, linking the past evolution with the present state of this geothermal system. The sulphur isotope signatures of the mineralization indicate a continuous decrease of the δ³⁴S of sulphate from +16.9‰ in the oldest barite to +10.1‰ in the present‐day thermal water. The δ³⁴S values of barite closely resemble various recently active thermal springs along the southern margin of the Rhenish Massif and contrast strongly with different regional ground and mineral waters. The mineralogical and isotopic signatures, combined with calculations based on uplift rates and the regional geological history, indicate a minimum activity of the thermal spring system at Wiesbaden of about 500 000 years. This timeframe is considerably larger than conservative models, which estimate the duration of thermal spring systems in continental intraplate settings to last for several 10 000 years. The calculated equilibrium sulphur isotope temperatures of coexisting barite and pyrite range between 65 and 80°C, close to the discharge temperature of the springs, which would indicate apparent equilibrium precipitation. Kinetic modelling of the re‐equilibration of the sulphate–sulphide pair during water ascent shows that this process would require 220 Myr. Therefore, we conclude that pyrite is formed from precursor Fe monosulphide phases, which rapidly precipitate in the near‐surface environment, preserving the isotope fractionation between dissolved sulphate and sulphide established in the deep aquifer. Equilibrium modelling of water–mineral reactions shows slight supersaturation of barite at the discharge temperature. Pyrite is already strongly supersaturated at the temperatures estimated for the aquifer (110°C) and processes in the near‐surface environment are most probably related to contact of the thermal water with atmospheric oxygen, resulting in formation of oxidized intermediate sulphur species and precipitation of Fe monosulphide phases, which subsequently recrystallize to pyrite.     

居民消费行为与城市生活空间行为规律研究

进入消费社会以后,社会经济的发展促使居民生活行为发生了很大的变化。消费作为居民日常生活的一部分,在社会空间秩序中起着越来越重要的作用。文章以"人本主义"地理学为出发点,应用数理统计和随机过程理论,结合影响居民消费行为的因素对居民消费行为的演进过程进行分析,来探讨城市居民消费行为与日常生活空间行为的关系,并总结出相应的居民消费生活空间行为规律。     

Expert‐Based Information and Policy Subsystems: A Review and Synthesis

This article reviews and synthesizes the uses of expert‐based information in policy subsystems. The review begins by summarizing the different uses of information in the multiple streams theory, the punctuated equilibrium theory, the social construction theory, and the advocacy coalition framework. Three uses of expert‐based information are identified as instrumental, learning, and political. The three uses of expert‐based information are then compared across unitary, collaborative, and adversarial policy subsystems. This article synthesizes the findings in a set of propositions about the use of expert‐based information in policy subsystems and about the factors that contribute to shifts from one policy subsystem to another.     

Solifluction-induced modifications of archaeological levels: simulation based on experimental data from a modern periglacial slope and application to French Palaeolithic sites

The taphonomic study of Petit-Bost, Croix-de-Canard and Cantalouette II, three Palaeolithic sites that were recently discovered near Périgueux and Bergerac (Dordogne, France) in a colluvial context, has enlightened the difficulty of adequately appreciating the relative role of cultural and natural processes in site spatial patterning. Periglacial solifluction was thought to have played a significant role in site formation. Because the nature of the modifications induced by solifluction was still poorly understood, a simulation was made using data of soil movement recorded at La Mortice (French Southern Alps, 3100 m in elevation) in a modern periglacial environment. The results show that, for a knapping location, the first steps of deformation are typified both by a downslope translation of the location center and by an anisotropic diffusion of the artifacts. The knapping spot becomes elongated along the slope, with a dense relic concentration of artifacts in the upslope portion. This type of pattern has been obtained after 100–200 years of simulated displacement according to the climatic and soil conditions that characterise the La Mortice site. The ultimate stages of deformation show that the artifact distribution tends to homogenise on larger surfaces and resemble a random distribution. The ability of the simulated patterns to closely fit those observed in archaeological contexts is evaluated at three sites from Southwestern France. At Petit-Bost, the hypothesis of limited solifluction explains accurately the association of both cultural (artifact concentrations) and natural (artifact preferred orientation) features. At Croix-de-Canard, long-term solifluction can be proposed. By contrast, the simulated patterns do not describe the structures observed on the steeper slopes at Cantalouette II, where the knapping spot transforms into distinct solifluction lobes.     

关于地层堆积和灰坑的几个问题

本文详细探讨了地层堆积、灰坑和界面等遗迹现象的概念、形成过程、方式、年代,以及相应的考古发掘清理和记录方法。     

Ceramic productions and human interactions during the Early Bronze Age in northern Iberia

The Early Bronze Age ceramic collection found into the caves of La Llana and El Toral III in Asturias (Spain) presents common decoration such as that found in the centre of Cantabrian Spain from the same period, which resembles others found in the Ebro Valley and Atlantic Europe. Therefore, the main objective of this study it is to identify the raw material origin and understand the pottery production process during the Early Bronze Age in the Cantabrian region. A methodological approach based on the chemical and mineralogical analysis of vessels and experimentally fired clay samples collected all over the centre of this region was developed. Furthermore, the post‐depositional processes affecting the sherds’ composition was evaluated by employing the rare earth elements as markers. The results showed that the studied assemblage has important similarities with the raw materials of the surrounding area, which supports the hypothesis of a regional mobility.     

Charcoal analyses as an environmental tool for the study of Early Medieval sunken houses infills in Roztoky near Prague, Czech Republic

The research was focused on the testing of possible information value of charcoal analysis from infills of archaeological objects, when methodologically different approaches are used in the combination with the micromorphological and pollen-analytical approach. The case study site chosen for this type of study is the unique Early Medieval settlement at Roztoky, Czech Republic. The comparative study includes the infills of 20 pithouses from the extensive settlement comprising about 750 (323 excavated) such archaeological structures situated along the left bank of Vltava River close to what today is the city of Prague. A combination of three anthracological outcomes (the number of charcoal fragments, the anthracomass, and the qualitative frequency of charcoal species) proves to be a powerful tool in determining the vegetation pattern in the surrounding landscape. The study revealed a major effect of post-depositional processes and quantification methods on the final anthracological interpretation. A modification of the anthracological record in different layers was traced in order to assess the applicability of sedimentology and micromorphology in the interpreting of the primary use and ending of the objects found. The reliability of anthracological interpretations are then compared with the results of micromorphological analyses and with regional vegetation patterns interpreted from pollen analyses of an off-site pollen profile.     

Skeletal analysis and mortuary practice in an Early Roman chamber tomb at Kenchreai,Greece

Recent exploration of the site of Kenchreai, the eastern port of Corinth in southern Greece, has focussed on a cemetery of subterranean chamber tombs dating chiefly to the Early Roman period (middle‐late 1st to 3rd centuries AD). The copious but fragmentary human bones and teeth found in Tomb 10 have been disturbed since burial by natural processes, including bedrock erosion and the infiltration of moisture, roots and basic sediment, and by destructive looters. Nonetheless, the remains furnish considerable information about the mortuary practices of wealthy residents. Analysis of the remains in their archaeological and taphonomic contexts reveals that Tomb 10 contained at least 23 individuals, 15 inhumed in loculi and 8 cremated and placed in niches, sometimes in urns. The identification of males, females and subadults among the burned and unburned bones and teeth suggests that spouses, parents and children probably from several generations of the same lineage or household were buried here. The nature of the cremated fragments reflects a laborious process during which mourners burned bodies on substantial pyres at extremely high temperatures for a long time. Then they carefully extracted a representative sample of small fragments from throughout the reduced skeleton for burial at the tomb. This study contributes to a better understanding of mortuary practices in the Roman East, particularly the Greek world, where the chamber tomb was a common sepulchral type. Copyright © 2009 John Wiley & Sons, Ltd.