In this intriguing and accessible book, Tyler Cowen explores the world of three amate artists, painting on paper made from the bark of trees from the mulberry family. Amate painting is an indigenous ...art form but one sold almost exclusively to wealthy North American art buyers or patrons. Cowen examines this cultural interaction between Mexico and the United States, showing how globalization shapes the lives and work of the artists and their families. He finds that, while the market for amate painting creates economic opportunities for the artists, it also has serious detrimental effects on the village.
Mediante fluorescencia de rayos X (FRX), se analizaron piezas arqueológicas hechas de obsidiana y muestras geológicas de obsidiana con el fin de discernir su ignoto origen. La obsidiana se produce en ...volcanes durante la expulsión y rápido enfriamiento de lava félsica con mínimo crecimiento de cristales. Los sitios de muestreo arqueológico están en el área de influencia de la cultura San Agustín, específicamente en el sitio conocido como Mesitas, ubicado dentro del Parque Arqueológico de San Agustín, en el Departamento del Huila (Colombia). Las piezas arqueológicas pertenecen a los periodos Formativo Temprano, Formativo Medio, Formativo Tardío, Clásico Regional y Reciente de dicha cultura. Los sitios de afloramiento y recolección de las muestras geológicas de obsidiana corresponden a cinco zonas próximas al parque arqueológico colombiano y otra al vecino país de Ecuador. Los resultados de esta investigación indican que la población aborigen del parque arqueológico no utilizó obsidiana extraída de las zonas geológicas cercanas. En consecuencia, las obsidianas procederían de áreas lejanas al parque, como resultado de intercambios mercantiles con grupos sociales distantes que tendrían mayor acceso a afloramientos de estas rocas volcánicas. Los resultados muestran la validez y fiabilidad del uso de la FRX como metodología para apoyar investigaciones de carácter arqueológico. ENGLISH: By means of X-ray fluorescence (XRF), archaeological artifacts made of obsidian and obsidian geological samples were analyzed in order to determine their unknown origin. Obsidian is produced in volcanoes during the expulsion and rapid cooling of felsic lava with minimal crystal growth. The archaeological sampling sites are in the influence area of the San Agustin culture, specifically in the site known as Mesitas, located within the San Agustin Archaeological Park, in the Department of Huila, Colombia. The archaeological artifacts belong to the Early Formative, Middle Formative, Late Formative, Regional Classic and Recent periods of this culture. The outcrop and collection sites of the obsidian geological samples are located in five areas near the Colombian archaeological park and another one in the neighboring country of Ecuador. The results of this research indicate that the aboriginal population of the archaeological park did not use obsidian extracted from nearby geological zones. Consequently, the obsidian would have come from areas far from the park, as a result of trade exchanges with distant social groups that would have greater access to outcrops of these volcanic rocks. The results show the validity and reliability of the XRF as a methodology to support archaeological research.
Paleoclimate records across the Intermountain West region of North America show significant regional variation in timing and magnitude of wet conditions that accompanied the last glacial-interglacial ...transition. To understand the climate controls on paleohydrologic change, well-dated records are needed across the region. The Plains of San Agustin (New Mexico, USA) is a closed-basin watershed of the American Southwest influenced by both winter westerly and summer North American Monsoon precipitation. The flat valley floors of the Plains contain lake and groundwater discharge deposits that record multiple periods of past wet climate. We present a record of hydroclimate for the past 26,000 years based on radiocarbon, U–Th series, and OSL dating of these deposits and stratigraphic correlation across the three sub-basins of the lake system. We find that two major lake oscillations occurred, coincident with the global Last Glacial Maximum (∼23–18 ka) and with Heinrich Stadial 1 (∼17–14 ka). The LGM lake cycle created a deep lake in the lowermost sub-basin, fed by marsh/lake overflow in the upper sub-basins. The Heinrich Stadial 1 wet interval attained the highest recorded lake level between ∼17.0 and 15.3 ka, merging the lower two sub-basins into one lake. Both lake cycles agree well in timing and magnitude with other lake-based records from the southwestern U.S., supporting previous interpretations that a south-shifted cool season storm track brought a dipole-like pattern of enhanced moisture to the southwest at the expense of drier conditions in the northwest during the LGM and deglaciation. A transition from lake to groundwater discharge conditions followed during the Bølling-Allerød (14.7–12.9 ka) across the study area. Wet meadows prevailed in the lower sub-basin during the Younger Dryas (12.9–11.7 ka), with marsh and open lake conditions in the upper and middle sub-basins, respectively. During the early Holocene, discrete wet intervals are recorded by ages for wet meadow deposits in all sub-basins with centennial-millennial frequency at 9.9, 8.8, 8.2 ka. These events agree well with other Intermountain West records showing wetter-than-present conditions prior to 8 ka. Two additional wet periods, centered at 6.8 and 5.4 ka, occurred during the driest known interval of the middle Holocene, and likely were partly supported in the Plains of San Agustin by summer moisture associated with the peak strength of the North American Monsoon. Our record highlights that both winter and summer moisture support water resources in New Mexico watersheds.
•We present a new lake level-based paleohydrologic history for the San Agustin Plains, New Mexico over the past 26,000 years.•Periods of deep lake conditions and high groundwater discharge coincided with the Last Glacial Maximum and Heinrich Stadial 1.•Lake drying occurred following the Bølling warming, but groundwater discharge persisted until the late Holocene.•Late Pleistocene deep lake conditions were driven by cold temperatures and enhanced winter season precipitation.•Holocene groundwater discharge was supported by cold/wet winters, but also by the mid-Holocene peak North American Monsoon.
This article examines some of the arguments of Saint Augustine’s De utilitate credendi, with the purpose of incorporate them in contemporary philosophical discussions about belief, testimony and ...tradition.
Premise of the study: Dated molecular phylogenies suggest a Cenozoic origin for the crown group of Equisetum. but compression fossil equisetaleans that are morphologically indistinguishable from ...extant Equisetum and recently discovered anatomically preserved examples strongly suggest an earlier Mesozoic initial diversification. Methods: In situ samples of Equisetum thermale sp. nov. from the Upper Jurassic San Agustin hot spring deposit were collected and studied with the use of polished blocks, thin sections, and light microscopy. Key results: Equisetum thermale exhibits all the morphological and anatomical characteristics of the extant crown group Equisetum. It shows a mixture of features present in the two extant subgenera, e.g., superficial stornata typical of subgenus Equisetum allied with infrequently ramifying stems typical of subgenus Hippochaete. This appears to ally E. thermale with the least derived extant species in the genus Equisetum bogotense (sister species to the two subgenera). Its association of hydromorphic and xeromorphic characters allowed it to grow as an emergent aquatic in physically and chemically stressed geothermally influenced wetlands, where it formed dense monospecific stands. Equisetum thermale, because it is preserved in situ with intact anatomy, provides clear paleoecological, biological, plus inferred paleoecophysiological evidence of adaptations known in extant species. Conclusions: As the earliest unequivocal member of the genus, E. thermale supports the hypothesis of a Mesozoic origin. Its inferred tolerance of a similar range of stresses (e.g., high salinity, alkalinity, and heavy metal concentrations) to that seen in extant Equisetum suggests early evolution and subsequent maintenance of ecophysiological innovations in the genus.
Herein we provide the first report of the diversity of fungi and fungus-like organisms within a Mesozoic hot spring ecosystem. The Jurassic San Agustín hot spring deposit (Patagonia, Argentina), ...represents only the second known Phanerozoic hot spring ecosystem with an associated microflora and contains diverse, exceptionally preserved microorganisms. Preserved propagules include flask-shaped pycnidia produced by extant coelomycetes, shield-like and nearly round thyriothecia of extant Microthyriales in the ascomycetes, variously shaped spore-like bodies representing chytrid and chytrid-like zoosporangia and other life cycle forms, and additional fungal and fungus-like remains (spores, hyphal fragments, reproductive structures) of uncertain affinity. Many of these microorganisms are associated with variously decayed organic remains, most commonly of horsetails. This expands the fungal fossil record and provides a unique opportunity to learn about the biology of Mesozoic microorganisms.
An article pondering theories of scarcity and how they relate to design, architecture and the built environment. The feature forms the introduction to an issue of 'AD' magazine, devoted to the theme ...of scarcity and architecture in an age of depleting resources.
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