Navegando por Assunto "Terra Preta Arqueológica"

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Acesso aberto (Open Access)
Contrastes químicos, mineralógicos e de fertilidade entre solos tipo terra preta arqueológica: sítio da Mata, no limite Oriental da Amazônia, e sítio Porto de Santarém, no Baixo Amazonas
(Universidade Federal do Pará, 2012-06-18) SILVA, Uibirá Sena; KERN, Dirse Clara; http://lattes.cnpq.br/8351785832221386; COSTA, Marcondes Lima da; http://lattes.cnpq.br/1639498384851302; https://orcid.org/0000-0002-0134-0432
Dark Earth sites are usually found in Amazonian Region. They stand out for their great content of ceramic fragments, urns, and lithic artifacts. Their soils present higher fertility if compared with the neighboring soils. Amazonian Dark Earths origins are related to pre-historic human activity of people who lived in ancient settlements in Amazonian Region for long periods of time. Recent researches reveal that the ceramic fragments from those sites present fertility as high as the soils, and even higher; and for that reason, when the ceramics fragments are exposed to weathering conditions, they could constitute in a potential source of nutrients for the soils that surround them. This study investigated the properties of soils and ceramic fragments from two ABE sites in distinct regions within the Amazon: Sítio da Mata, in São Luís City, Estate of Maranhão, region of forest-savanna transition; and Sítio Porto de Santarém, at the Tapajós River’s outfall, a former rain forest area that is currently intensively urbanized. This research aimed to characterize and compare the material from both sites, and correlate them to de different geomorphologic contexts in which they’re inserted. In the Sítio da Mata was sampled material from the ABE soil profile and from adjacent soil profile, and in Sítio Porto de Santarém, was sampled material only in the ABE soil profile. The samples comprised both soil and ceramic fragments matrices. The material was subjected to particle size analysis (soil samples only), X-Ray Diffraction (XRD) analysis, total chemical analysis by ICP-MS/OES, and fertility parameters analysis. Phosphorus fractionation was also performed in aim to determine the phosphorus species (P-Ca, P-Fe-Al, and organic P) present in soils and ceramic fragments samples. This study investigated the properties of soils and ceramic fragments from two ABE sites in distinct regions within the Amazon: Sítio da Mata, in São Luís City, Estate of Maranhão, region of forest-savanna transition; and Sítio Porto de Santarém, at the Tapajós River’s outfall, a former rain forest area that is currently intensively urbanized. This research aimed to characterize and compare the material from both sites, and correlate them to de different geomorphologic contexts in which they’re inserted. In the Sítio da Mata was sampled material from the ABE soil profile and from adjacent soil profile, and in Sítio Porto de Santarém, was sampled material only in the ABE soil profile. The samples comprised both soil and ceramic fragments matrices. The material was submitted to particle size analysis (soil samples only), X-Ray Diffraction (XRD) analysis, total chemical analysis by ICP-MS/OES, and fertility parameters analysis. Phosphorus fractionation was also performed in aim to determine the phosphorus species (P-Ca, P-Fe-Al, and organic P) present in soils and ceramic fragments samples. ABE from both sites showed high contents of the sand fraction, and soil texture varied from silty-loam to loam sand in Sítio da Mata and sandyloam in the entire ABE profile in Sítio Porto de Santarém. Mineralogical composition in both soils showed no significant differences: they consist most of quartz and kaolinite as primary mineral phases, and anatase and muscovite as accessory mineral phases. Chemical analysis reveal that the soils are composed most for SiO2 and Al2O3, confirming the mineralogical results, and Fe2O3 and TiO2 in minor quantities. P2O5, CaO, K2O and MgO are present in amounts below 0,5%, however, they show higher values in the soils from Sítio Porto de Santarém if compared to Sítio da Mata. Among the trace elements analyzed, only V, Cu, Zn, Sr and Ba stand out, and also show higher values in Sítio Porto de Santarém’s soils. Amounts and distribution patterns for Rare Earth Elements (REE), when normalized by condrits, are similar in both sites, showing enrichment of Light REE, strong positive anomaly for Ce, and negative anomaly for Eu. Differences only in the available P, Ca2+ and Mg2+ contents, although in relatively low values, suggest different anthropic influence over the pre-ABE soils. ABE soils from Sítio Porto de Santarém show higher fertility given for the higher contents of available P, ranging from 72,9 to 305,7 mg Kg-1, and Ca2+, ranging from 3,52 to 5,16 mg Kg-1, compared to 5,4 to 12,7 mg Kg-1 of P content and 0,96 to 2,31 mg Kg-1 of Ca2+ content in Sítio da Mata’s soils. Cation Exchange Capacity (CEC), sum of bases, base saturation and soil organic matter (SOM) were also higher in ABE from Sítio Porto de Santarém. Ceramic fragments from both sites are composed by quartz and metakaolinite, and also illite and anatase. Albite and microcline were detected only in ceramic fragments from Sítio Porto de Santarém. Therefore, they are composed mainly by SiO2 and Al2O3, and in smaller amounts, by Fe2O3 and TiO2. At Santarém, however, ceramic fragments contain also high amounts of P2O5, ranging from 3,49% to 5,37%, and the values for CaO, K2O, Na2O, Cu, Zn, Sr and Ba exceed those from Sítio da Mata. The contents and distribution pattern for REE are similar in ceramic fragments from both sites, with enrichment of LREE, positive anomaly for Ce and negative anomalies for Eu and Ho. Therefore, the ceramic fragments from both sites are mineralogicaly distinct, although they’re immersed in a similar soil matrix. The presence of phosphorus is compatible with others ceramic fragments found in different ABE sites. The fertility of ceramic fragments from Sítio Porto de Santarém showed better rates, with slightly higher pH if compared to ceramic fragments from Sítio da Mata, higher amounts of available Ca2+, K+ and mainly available P, besides higher CEC, sum of bases and base saturation, corroborating the higher fertility of the soils from Sítio Porto de Santarém. Phosphorus fractionation shows that in soil matrix from the studied sites, phosphorus is mainly related to organic compounds, while in ceramic fragments matrix, it is mainly related to nonapatite inorganic compounds. Apatite phosphorus is present in small amounts in both soil and ceramic fragments matrices. Therefore, it is likely that phosphorus present in organic material discarded by ancient people, as various kind of bones, among others, when submitted to tropical pedogenesis, were gradually dissolved, releasing phosphorus, which was partially fixed as Fe-Al phosphates, common mineral phases in tropical soils, as well as organic matter, abundant in ABE, respectively representing the nonapatite inorganic phosphorus and the organic phosphorus fractions.
Acesso aberto (Open Access)
Fertilidade, caracterização química, mineralogia e morfologia de cerâmicas e solos de terra preta arqueológica do Sambaqui Jacarequara (Barcarena-Pa)
(Universidade Federal do Pará, 2015-07-08) REIS, André Heron Carvalho dos; SILVEIRA, Maura Imazio da; http://lattes.cnpq.br/1937795556101203; COSTA, Marcondes Lima da; http://lattes.cnpq.br/1639498384851302
Archaeological Black earth (ABE) are soil stains easily found in archaeological sites. Their dark color and fertility contrasts with adjacent soils, which are usually poor in nutrients. Their formation is related to disposal of organic matter coming from old indian villages, besides the presence of “lítico” artifacts, coal and various ceramic fragments of different styles and traditions. However, researches aimed to evaluate the morfology of the ceramic set, its chemical and mineralogical characteristics and also the assessment of the sambaquis’ fertility still rare. These researches may contribute to a great advance in the knowlegde of ABE and its fertility. In addition, they may elucidate some aspects about the living style of the groups involved. This paper aims to advance in this problematic when analising the ceramic fragments (decorated or not decorated) and the archeo- stratigrafic soil layers (defined by cultural and natural features) from the Sambaqui Jacarequara ABE, in Barcarena, Pará. The samples were submitted to chemical and mineralogical analisis by ICP-MS, ICP-OES, DRX, MEV/EDS, optical microscopy, the assessmente of soil fertility and morfological analises (stylistic and technical aspects) of the sambaqui ceramic set. Regarding to the soils, the obtained data demosntrate and high fertility (V >87 e SB >10), light and strongly basic pH (6,02-8,25), a high concentration of P is avaiable (46,5-818,1 mg/dm3), and the amount of the bases composed predominantly by por Ca e Mg, reflecting the chemical composition of the carbonatic material added. These values are highighted in the layers 2, 3B and 3A with major availability P and Ca, while these values are reduced considerably in the base (Layer 6). The soils are predominantly composed by SiO2, Al2O3, CaO, Fe2O3, K2O e MgO (85, 37 %), which refletcs the mineralogy composed by quartz, calcite, argonite, kaolinite. The concentration of P2O5 is considered low (0, 46 %) when compared with the other ABE in the Amazon, possibly presented in amorphous phase. When confrotating with the crustal avarage is visible the slightly high values of SiO2, CaO, TiO2, P2O5 e MnO. In turn, the ceramics shows basic pH (7, 04-8, 00), high values of sum and base saturation (SB >29, 42; V >94, 7) demosntrating their high fertility level. The P avaiable indicates lower values in the ceramics than in the soil (12-389, 9 mg/dm3 ) displaying the FCs contribution to the soil fertility. Their chemical composition is composed by SiO2, Al2O3, CaO, Fe2O3, K2O, TiO2 P2O5 (75, 33 %). 1 0 Mineralogicaly, the ceramics do not differ from the soil, indicating a local origin to the raw material sources. These ones are composed by quartz phases, musccovite, calcite, argonite, anatase, besides the amorphous phase of metakaolinite, which suggests a burning superior to 550ºC. Crystalline stages related to phosphorus were not found. When confronting chemical data with the ceramics morphology, it is possible to notice that fragments with higher volumetric capacity, fined-grained and lower concentrations of grounded shells in the Clay have a higher concentration of P (> 0,70 %), indicating a possible relation between the materials used during the ceramics fabrication, their use and chemical signature. Morphologically, the results qualified the ceramics in the Regional traditional Mina. However, some variations in the decorative patterns were found between the stratigrafic levels: profile’s basis, one occupation composed by ceramics of introverted forms, fined grained, red engobes e major diversity in the antiplastic use, while from layer 3 there is some ceramics characterized by shells with higher fined-grained, plates with plastic decorations (incised, hand-carved) and fragments much more with the absence od engobe. Therefore, it is concluded that the FCs are fundamental to the maintainance of the fertility of the ABE and also the dissimilarities among chemistry, mineralogy, texture and technology of the ceramics of each layer. It also defines three phases of occupation to the sambaqui: the first phase indicates they would have occupied a promontory of the beach next to the river with the use of aquatics resources in temporary villages; the second one demonstrates a permanent use of the area and intense fishing activity with disposal of organic matter in the soils resulting in the ABE; while the last one demonstrates a post sambaqui occupation with fewer dependence of aquatic resources.