Rita Scheel-Ybert

A TENTATIVE DETERMINATION OF UPWELLING INFLUENCE ON THE PALEO- SURFICIAL MARINE WATER RESERVOIR EFFECT IN SOUTHEASTERN BRAZIL

Previous work has suggested that seasonal and interannual upwelling of deep, cold, radiocarbon-depleted waters from the South Atlantic has caused variations in the reservoir effect (R) through time along the southern coast of Bra- zil. This work aims to examine the possible upwelling influence on the paleoreservoir age of Brazilian surficial coastal waters based on paired terrestrial/marine samples obtained from archaeological remains. On the Brazilian coast, there are hundreds of shell middens built up by an ancient culture that lived between 6500 to 1500 yr ago, but there are few shell middens located on open-coast sites with a known upwelling influence. Three archaeological sites located in a large headland in Arraial do Cabo and Ilha de Cabo Frio on the southeastern coast of Brazil, with open-ocean conditions and a well-known strong and large upwelling of the Malvinas/Falkland current, were chosen for this study. The 14C age differences between carbonized seed and marine samples varied from 281 ± 44 to 1083 ± 51 14C yr. There are also significant age differences between car- bonized seed samples (977 14C yr) and marine samples (200 and 228 14C yr) from the same archaeological layer that cannot be explained by a reservoir effect or an old-wood effect for charcoal. Therefore, the present data from the southeastern Bra- zilian coast are inconclusive for identifying an upwelling effect on R. To do so, it would be necessary to more precisely define the present-pre-bomb R in upwelling regions, and to analyze paired marine/terrestrial samples that are contemporaneous beyond doubt.

THE EFFECT OF CARBONIZATION ON WOOD STRUCTURE OF DALBERGIA VIOLACEA, STRYPHNODENDRON POLYPHYLLUM, TAPIRIRA GUIANENSIS, VOCHYSIA TUCANORUM, AND POUTERIA TORTA FROM THE BRAZILIAN CERRADO

Summary Brazil is the world’s largest producer of charcoal and a great part of this material still comes from native forests – especially from the cerrado biome, which is highly impacted by anthropogenic degradation. The need to control charcoal production increases the demand of charcoal identifi cation, but there is little information about the anatomical modifications due to carbonization. In this paper, fresh and charred wood samples from five Brazilian species were analyzed (Dalbergia violacea , Stryphnodendron polyphyllum, Tapirira guianensis, Vochysia tucanorum, and Pouteria torta). anatomical characters were described and measurements of the main anatomical features of wood and charcoal were statistically compared. Minor modifications were observed: reduction of tangential vessel diameter was the most evident change after carbonization; shrinkage of rays (in width) occurred only in some individuals. The present study supports the identification of charred woods, hopefully contributing to the control of charcoal production, and to palaeoenvironmental and archaeobotanical studies.

The Long-Term Tupiguarani Occupation in Southeastern Brazil

We discuss some aspects of the chronology of the Tupiguarani occupation in the southeastern Brazilian coast based on the analyses of 3 charcoal samples from the Morro Grande archaeological site (Rio de Janeiro state). 14C beta spectroscopy and accelerator mass spectrometry (AMS) techniques were used to determine ages of 2920 ± 70 BP, 2600 ± 160 BP, and 510 ± 160 BP. The occurrence of these ancient dates in southeastern Brazil has important implications for understanding the origin and dispersion of Tupian populations from Amazonia, supporting recent hypotheses that their expansion must have begun well before 2000 BP. On the other hand, the most recent date is a strong indication of a possible reoccupation of the site by the same cultural group around the time. These results show that the Tupiguarani occupation began at least about 3000 yr ago and lasted until its collapse with the European invasion in the 16th century.

CHARCOAL COLLECTIONS OF THE WORLD

Charcoal reference collections are very important for identifying unknown charcoal specimens in different contexts (palaeoecological, archaeological, environmental and others) and form an integral part of anthracological studies, which can provide crucial information for researchers of different expertise, as wood anatomy, archaeology, palaeobotany, forestry, forensics, etc. A first inventory on charcoal collections maintained by scientific institutions or private individuals around the world revealed 53 charcoal collections in five continents. There is a high concentration of collections and specimens in Europe, reflecting a better established and longer tradition of charcoal identification in temperate and mediterranean regions. However, research seems to be firmly advancing in other parts of the world, especially in the tropics, where important collections are being established. The great increase observed in the number of existing charcoal collections and their geographical spread in the last years attest to their importance, as well as to the vigour of anthracology in its various approaches. The wood anatomical community is called upon to help fill gaps in this first inventory of charcoal collections.

Charcoal anatomy of Brazilian species. I. Anacardiaceae

Anthracological studies are firmly advancing in the tropics during the last decades. The theoretical and methodological bases of the discipline are well established. Yet, there is a strong demand for comparative reference material, seeking for an improvement in the precision of taxonomic determination, both in palaeoecological and palaeoethnobotanical studies and to help preventing illegal charcoal production. This work presents descriptions of charcoal anatomy of eleven Anacardiaceae species from six genera native to Brazil (Anacardium occidentale, Anacardium parvifolium, Astronium graveolens, Astronium lecointei, Lithrea molleoides, Schinus terebenthifolius, Spondias mombin, Spondias purpurea, Spondias tuberosa, Tapirira guianensis, and Tapirira obtusa). They are characterized by diffuse-porous wood, vessels solitary and in multiples, tyloses and spiral thickenings sometimes present; simple perforation plates, alternate intervessel pits, rounded vessel-ray pits with much reduced borders to apparently simple; parenchyma paratracheal scanty to vasicentric; heterocellular rays, some with radial canals and crystals; septate fibres with simple pits. These results are quite similar to previous wood anatomical descriptions of the same species or genera. Yet, charcoal identification is more effective when unknown samples are compared to charred extant equivalents, instead of to wood slides.

Recuperação de macrovestígios em sítios arqueológicos na Amazônia: nova proposta metodológica para estudos arqueobotânicos

The recovery of plant macroremains for archaeobotanical analyses requires the adaptation of the methods to different environments found in archaeological sites around the world. In the Amazon, clayey soils frequently complicate the recovery of organic and inorganic remains due to the propensity of clay particles to aggregate. This note presents the methodology employed in the treatment of sediment samples from archaeological sites in the central Amazon, highlighting the use of deflocculants associated to flotation. Minimizing the sample biases during the recovery of plant macroremains will allow for better and more accurate results from archaeobotanical analyses.