No description available.

No description available.

No description available.

The Jaguar Baby vessels belong to a large corpus of Late Classic Maya pictorial ceramics dubbed Codex-style pottery and originating from archaeological sites, such as El Mirador and Nakbe, in the north-central area of Peten, Guatemala, where they were made for a brief period shortly before and/or after the turn of the eighth century AD. Through strategic juxtapositions of images and words, the vessels convey the story of a rain god and a death spirit who, in the darkness between the sun’s setting and dawn, sacrifice an infant, a jaguar, or an infant with jaguar traits on a mountain in the midst of water, as an offering during the conjuring of an elderly deity. New evidence from a fragmentary Codex-style vessel recovered from the site of Calakmul in the southern half of Campeche, Mexico, suggests that the sacrifice is part of a pre-accession ritual serving to endow royal heirs with the ability to conjure, which, in turn, was integral to assuming the throne. / text

Tropical forests provide important habitat for a tremendous diversity of plant and animal species. However, limitations in measuring and monitoring the structure and function of tropical forests has caused these systems to remain poorly understood. Remote-sensing technology has provided a powerful tool for quantification of structural patterns and associating these with resource use. Satellite and aerial platforms can be used to collect remotely sensed images of tropical forests that can be applied to ecological research and management. Chapter 1 of this article highlights the resources available for tropical forest remote sensing and presents a case-study that demonstrates its application to a neotropical forest located in the Petén region of northern Guatemala. The ancient polity of Tikal has been extensively studied by archaeologists and soil scientists, but little is known about the subsistence and ancient farming techniques that sustained its inhabitants. The objective of chapter 2 was to create predictive models for ancient maize (Zea mays L.) agriculture in the Tikal National Park, Petén, Guatemala, improving our understanding of settlement patterns and the ecological potentials surrounding the site in a cost effective manner. Ancient maize agriculture was described in this study as carbon (C) isotopic signatures left in the soil humin fraction. Probability models predicting C isotopic enrichment and carbonate C were used to outline areas of potential long term maize agriculture. It was found that the Tikal area not only supports a great variety of potential food production systems but the models suggest multiple maize agricultural practices were used.

Triple oxygen and hydrogen isotope analysis of the structurally-bound water in gypsum can provide a direct measure of past hydrologic variability. This thesis presents the development of the water extraction and isotopic measurement procedures, the calculation of the gypsum-water isotope fractionation factors, and the application of the method to constrain the palaeohydrologic conditions in two temporally and geographically disparate sites. Measurement of the isotopic composition of gypsum hydration water is used to examine the hydrological changes that occurred during the Terminal Classic Drought of the Maya lowlands (~800-1000 CE), coincident with the period when the Classic Maya Civilization of Mesoamerica collapsed. The data provide a complete and direct archive of hydrological conditions that have previously been limited to ice core records. Mean annual rainfall is shown to have decreased by between 41% and 54%, with intervals of up to 70%, compared to present-day conditions. This study has also shown for the first time that relative humidity was 2%-7% lower during the Terminal Classic Drought compared to today. The methodology is also applied to the massive gypsum deposits in the marginal and deep basins of the Mediterranean to interpret the chemical evolution of parent water bodies during the Messinian Salinity Crisis (5.97-5.3 Ma). By combining the measurement of gypsum hydration water with other traditional (e.g. strontium) and novel (e.g. calcium and barium) isotope tracers, the hydrological changes during the deposition of Primary Lower Gypsum units of the Sorbas Basin in southeastern Spain, the Upper Gypsum units of Sicily, and deep basin deposits have been constrained. The results indicate that all deposits experienced a significant freshwater contribution to the mother fluids from which they formed. It is proposed that obliquity-controlled sea level and eccentricity-modulated precession, superimposed on longer-term tectonic restriction of the Mediterranean-Atlantic exchange, together controlled the varying depositional environments during the formation of the Messinian Salt Giant. This thesis demonstrates that the analysis of gypsum hydration water is a powerful tool for palaeoclimate reconstruction. The methodology can be applied to gypsum (and other hydrated minerals) in a wide range of settings across geological space and time, providing a rich source of information about the environmental conditions under which they formed.

No description available.

Kollapsen av den klassiska Mayakulturen under sen 700- till sen 900-tal e.Kr. har förbluffat forskare ända sedan studier av Mayakulturen påbörjades på 1840-talet. Både arkeologer och antropologer som epigrafiker eller klimatforskare har arbetat med att lösa gåtan av hur ett kulturellt vidsträckt samhälle kunde kollapsa utan någon klar förklaring. Civilisationen som än idag talar till oss genom sina kolossala pyramider och tempel, inskriptioner och den vetenskapliga kunskapen som ansetts outförbara utan moderna instrument. Dock har inte kollapsen varit ett direkt fokus i Mayastudier sedan forskningen påbörjades. Det var inte förrän på 1960-talet som systematiska undersökningar utfördes för att hitta rimliga teorier till kollapsen. Ända sedan dess har hypoteser och teorier haglat in och forskarna idag hittar sig själva i en sjö av oförklarlig information. Kunskapen av Mayakulturen är enorm men det har inte hjälpt att hitta någon bestämd teori om kollapsen av klassiska Maya. Det finns forskare som fokuserar på stora katastrofala händelser såsom drastiska klimatförändringar, sjukdomar eller jordbävningar så svåra att återhämtning var omöjligt. Sedan finns den andra skaran av forskare som förkastar enskilda händelser och fokuserar mer på mångfaldiga katastrofer som kunnat utlösa ödesdigra mönster i samhället som till slut utmynnat i en kollaps. Trots oklarheter kring kollapsen har framsteg gjorts inom fältet. Många teorier har mycket tack vare avancerade metoder kunnat förkastas medan andra blivit mer debatterade. Vad som än Mayakulturen kan berätta för oss, står ändå kollapsen som den stora nöten att knäcka och ju längre forskningen av ämnet fortgår desto närmare kommer även forskare till svaret. Frågor dyker dock fortfarande upp om det är möjligt att lösa en av arkeologins stora gåtor.