2021 ◽  
pp. 1-15
Author(s):  
Andrew D. Somerville ◽  
Isabel Casar ◽  
Joaquín Arroyo-Cabrales

Archaeological studies at Coxcatlan Cave in the Tehuacan Valley of southern Puebla, Mexico, have been instrumental to the development of the chronology for the region and for our understanding of the origins of food production in the Americas. This article refines the Preceramic chronology of the Tehuacan Valley by presenting 14 new accelerated mass spectrometry (AMS) radiocarbon ages from faunal bone samples uncovered from early depositional levels of the rock shelter. Although bones associated with the El Riego (9893–7838 cal BP), Coxcatlan (7838–6375 cal BP), and Abejas (6375–4545 cal BP) phase zones of the cave yielded ages similar to those of the previously proposed chronology for the region, bones from the Ajuereado phase zones at the base of the cave yielded surprisingly old ages that range from 33,448 to 28,279 cal BP, a time prior to the Last Glacial Maximum. Because these early ages are many thousands of years older than current models estimate for the peopling of the Americas, they require reassessments of the artifacts and ecofacts excavated from these early zones.


1997 ◽  
Vol 11 (2) ◽  
pp. 367-374 ◽  
Author(s):  
Yuria Cardel ◽  
Victor Rico-Gray ◽  
José G. García-Franco ◽  
Leonard B. Thien

1999 ◽  
Vol 77 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Héctor Godínez-Alvarez ◽  
Alfonso Valiente-Banuet ◽  
Leopoldo Valiente Banuet

The giant columnar cactus Neobuxbaumia tetetzo (Coulter) Backeberg is the dominant species of a vegetation type locally called "tetechera" that occupies ca. 400 km2 in the Tehuacán Valley. As a way to analyse the role of biotic interactions on the population dynamics of this species, we conducted an elasticity analysis, using matrix models elaborated from field data, to determine the finite rate of increase and the critical stages of the life cycle that were related to the biotic interactions occurring during these stages. Although the estimated finite rate of increase did not differ from unity there were significant differences between the actual and predicted size distributions. Elasticity analysis showed that survivorship was the most important life-history parameter to the finite rate of increase. Because survivorship depends on the presence of nurse plants, our results emphasise the importance of positive interactions on the population dynamics of long-lived columnar cacti.Key words: biotic interactions, Cactaceae, deserts, matrix models, population dynamics.


2007 ◽  
Vol 68 (1) ◽  
pp. 1-8 ◽  
Author(s):  
A. Valiente-Banuet ◽  
R. Santos Gally ◽  
M.C. Arizmendi ◽  
A. Casas

Antiquity ◽  
2001 ◽  
Vol 75 (289) ◽  
pp. 505-506 ◽  
Author(s):  
James A. Neely

Nearly three decades ago, Woodbury & Neely (1972) published the first analysis of the extensive and complex system of Prehispanic Canals found in the northern portion of the Tehuacan Valley of Puebla, Mexico. These springfed canals, functioning to supply waters for irrigation and domestic uses, were uniquely preserved in near entirety by natural processes. The canals have been ‘fossilized’ in place through a process of mineral deposition. They are clearly visible on the landscape for many kilometres and have aggraded in height, now standing 2 to 3 m high in several places. Time, funding and the archaeological methodology of the mid 1960s limited Woodbury & Neely’s fieldwork, and therefore the study did not fully investigate the system. Although a basic description and discussion of the technology and functioning of the system was accomplished, a detailed analysis of these aspects remained to be done. A schematic mapping of the system was accomplished, but an accurate mapping of the canals and associated habitation and administrative sites was lacking. The chronological placement of these canals was attempted by means of the cross-dating of ceramics on archaeological sites found bordering the channels, but an accurate chronological sequence of the system’s development was not attainable. A general climatic reconstruction of the valley was generated, but since the emphasis placed by the Tehuacan Archaeological and Botanical Project was on the earlier periods of habitation that focused on the development of maize domestication, the climatic contexts into which the canals were later constructed was not known.


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