Navegando por Autor "RODRIGUES, Suyanne Flavia Santos"

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Acesso aberto (Open Access)
Os fragmentos de cerâmica arqueológica como fonte potencial de fertilidade dos solos TPA
(Universidade Federal do Pará, 2014-09-26) RODRIGUES, Suyanne Flavia Santos; KERN, Dirse Clara; http://lattes.cnpq.br/8351785832221386; COSTA, Marcondes Lima da; http://lattes.cnpq.br/1639498384851302
Soils of the Amazon Dark Earth (ADE) type are known for their high fertility, which contrasts with the typically poor soils found throughout most of the Amazon. The fertility of these soils appears to persist even after their intensive use for agriculture. The ADE are usually rich in sherds, important evidence linking them to the occupation of the region by prehistoric populations. Many studies have focused on the stylistic characteristics of the vessels represented by these sherds, although less attention has been paid to the chemical and mineralogical features of this material, which are important for the identification of the raw material use to produce the artifacts, provenience, technology, and in particular the origin of their relatively high P content. These high levels of P are derived from aluminum phosphates, which are generally amorphous to variscite-strengite, and have been linked to the use of the pots for the preparation of food. While the possible role of the sherds in the maintenance of the fertility of ADE has been widely discussed, no experimental data have been presented to confirm this connection. This study presents systematic evidence that the sherds contribute to the fertility of the soils. For this, sherds were obtained from three archeological sites with distinct characteristics located in different parts of the Amazon: Monte Dourado 1 (Almeirim, Pará), Jabuti (Bragança, Pará), and Da Mata (São José de Ribamar, Maranhão). Initially, 325 sherds were first described mesoscopically and then their chemical and mineralogical composition was determined by XRD, optical microscopy, TGA/DTA, FT-IR, SEM-EDS, ICP-MS and ICP-OES. Different parameters of fertility were then measured, followed by gaseous adsorption tests, and finally, P desorption assays. These data were used to identify the raw materials used in the fabrication of the vessels, details of the productive process, modifications occurring during the use of the utensils and after being discarded, with the aim of evaluating the potential contribution of these sherds to the fertility of the ADE soils. The hypothesis of contamination by nutrients from foods during the use of the vessels for the preparation of meals was confirmed by a laboratory experiment simulating cooking conditions using ceramic pots similar to the archeological artifacts, and measuring the incorporation of Ca and P during the cooking process. The results indicate that the ancient ceramicist peoples used raw materials available in the area surrounding their habitation sites. The composition of the sherds, all of which are made from a matrix of metakaolinite and quartz, and occasionally muscovite, indicating raw materials rich in kaolinite and quartz, which are fundamental to the production of ceramic artifacts. The presence of metakaolinite indicates that the pots were fired at approximately 550°C. However, the addition of different types of antiplastic contributed to chemical and mineralogical variation among sites in the overall composition of the sherds. At Da Mata, only cariapé was used, while at Monte Dourado 1, the cariapé was mixed with crushed rocks with a complex mineralogical content, and at Jabuti, shells were used in addition to cariapé. Amorphous phosphates are common to all the sites, albeit at distinct levels, with crystalline aluminum phosphates of the crandallite-goyazite type being found only at Jabuti, and Fe-Mg-Ca phosphates, segelerite, being exclusive to Monte Dourado 1. The amorphous phosphates and crandallite-goyazite were considered to be indicators of the use of the original pots (from which the sherds were derived) for the preparation of food, whereas the segelerite was interpreted as a neoformation following exposure of the fragments to the hydromorphic conditions that persist to the present day. The lowest phosphorus concentrations-1.04% of P2O5 on average- were recorded at Da Mata, and were similar to the majority of sherds studied up until now, whereas the highest concentrations (a mean of 7.75%) were recorded at Jabuti, the highest values yet reported. At Monte Dourado 1, the mean concentration was 2.23%. It seems likely that the high levels of P, Ca, and Sr are related to a diet rich in shellfish, as reflected in the diversity of shells fragments found in the sherds. The high levels of calcium recorded at Monte Dourado 1 reflect the presence of labradorite in the temper. The potential fertility of the sherds is clearly greater than that of the ADE soil when analyzed without the ceramics. It thus seems reasonable to assume that the sherds are the source of the macro- and micronutrients found in the soil. This was confirmed through desorption assays, which showed that P was desorbed at a slow rate, a characteristic which may be especially important for the persistence of fertility. This process is best described by the Freundlich model, which indicates the occurrence of interactions among the adsorbed ions. The experiment that simulated cooking conditions indicated that the Ca and P may be adsorbed into both the sides and lids of the ceramic pots, albeit with higher concentrations being accumulated in the sides. While calcium was adsorbed, no phase of this element was identified, either amorphous or crystalline, probably because the duration of the experiment was too short. By contrast, the chemical adsorption of the P did occur, and after 600 h of cooking, variscite, an aluminum phosphate, formed in the sides of the pots. Aluminum phosphates may thus form in the ceramic vessels during the cooking of food. These results indicate that the presence of aluminum phosphates in the matrix of the ceramic vessels represents a reliable indicator of their use as cooking vessels, and that the sherds of these utensils in the soil constitute a potentially important source of fertility.
Acesso aberto (Open Access)
Jarina: o marfim das biojóias da Amazônia
(2006-12) COSTA, Marcondes Lima da; RODRIGUES, Suyanne Flavia Santos; HOHN, Helmut
The jarina palm tree (Phytelephas macrocarpa) is endemic of the Amazon region growing in older flood plains constituted by quartz, 2:1 clay-minerals and feldspars. The soils are fertile and slightly acid to neutral. The jarina seeds can be included among the rare organic gems. Because of its color and luster the seeds are compared to animal ivory in spite of its lower hardness and lower density. They are largely employed in the manufacture of bio-jewels and artifacts. The products are commercially well accepted because the seeds support coloration change and other improvements. However, the jewels do not last very long because the seeds tend to be destroyed by the action of microorganisms within 5 to 10 years. By means of an adequate policy the productive chain of jarina seeds may turn to be of great importance for the development of the Amazon region by creating new job opportunities and by aggregating value to the products. However, special care has to be taken to avoid inadequate exploration of the seeds in order to assure the preservation of the species.
Acesso aberto (Open Access)
Mineralogical and geochemical influences on sediment color of Amazon wetlands analyzed by visible spectrophotometry
(Instituto Nacional de Pesquisas da Amazônia, 2013-09) GUIMARÃES, José Tasso Felix; COHEN, Marcelo Cancela Lisboa; FRANÇA, Marlon Carlos; SILVA, Any Kelly Terra da; RODRIGUES, Suyanne Flavia Santos
Based on sedimentological and geochemical data, this work relates spectrophotometric measurements with sediment composition and its application in palaeoecological studies of Amazon wetlands. The CIELAB values are directly related to mineralogical and chemical composition, mostly involving quartz, iron oxyhydroxides and sulfides (e.g. pyrite), and total organic carbon. Total organic carbon contents between 0.4-1%, 1-2%, 3-5% and 15-40% were related to L* (lightness) data of 27, 26-15, 7-10 and 7 or less, respectively. The CIELAB values of a deposit in Marabá, Pará, were proportional to variations in quartz and total organic carbon contents, but changes in zones of similar color, mainly in the +a* (red) and +b* (yellow) values of deposits in Calçoene, Amapá and Soure, Pará, indicate a close relationship between total organic carbon content and iron oxyhydroxides and sulfides. Furthermore, the Q7/4 diagram (ratio between the % re?ectance value at 700 nm to that at 400 nm, coupled with L*) indicated iron-rich sediments in the bioturbated mud facies of the Amapá deposit, bioturbated mud and bioturbated sand facies of Soure deposit, and cross-laminated sand and massive sand facies of the Marabá core. Also, organic-rich sediments were found in the bioturbated mud facies of the Amapá deposit, lenticular heterolithic and bioturbated mud facies of the Soure deposit, and laminated mud and peat facies of the Marabá deposit. At the Marabá site, the data suggest an autochthonous influence with peat formation. The coastal wetland sites at Marajó and Amapá represent the development of a typical tidal flat setting with sulfide and iron oxyhydroxides formation during alternated ?ooding and drying.