Paleoenvironmental and archeological significance of alluvial placers of the Brazilian Amazon

The gold and tin-bearing alluvial placers of the Brazilian Amazon high terrains constitute a remarkable record of the environmental changes which occurred in the region during the Quaternary. The deposits are typically immature, and have been formed by mass movements under semi-arid climate. They are clearly older than the last rain forest spreading, and may be attributed to cyclic episodes which have been correlated to the Pleistocene glaciations. These interpretations are highlighted by the discovery of abundant polished stone artifacts which have been preserved within Pleistocene deposits. The archeological record allows the demarcation of an important cultural tradition, widely disseminated in the Brazilian Amazon, and gives a starting point to review our present knowledge of the Amazonian Prehistory - still centered in studies on the Várzea" region, of Holocene age. This means that the human establishment in the Amazon is much older than formerly believed

Sistemas silvipastoris na Amazônia Oriental.

A problemática das pastagens. Os sistemas silvipastoris (SSP). O papel da árvore. Interação árvore - pastagem. Componente animal. Sistemas silvipastoris praticados na Amazônia Oriental. Avaliação de sistemas silvipastoris. Adoção de sistemas silvipastoris.bitstream/item/63268/1/Oriental-Doc56.pd

Organic carbon accumulation in coastal zones since the last glacial maximum? A clue for varying atmospheric CO2 levels?

It is a generally accepted concept that the carbon storage within the principal earth surface reservoirs varies in a multitude of time scales. The shallow water continental margins belong to the most fertile areas in terms of organic carbon (OC) production and are also very effective carbon traps

The material sources and processes during the infilling of estuaries in Algarve (South Portugal)

The actual estuary that occupies the Boina-Arade paleovalley accommodated the Holocene sedimentary sequence whose thickness does not exceed 35 m in the deepest zones, as registered from geotechnical borehole data. We present here the results of partial analyses of two continuous cores which cross the Holocene sequence until the Pre-Quaternary substratum. In the P5 core (Boina river), the sedimentary column, which spans 20 m accumulated during ca 8500 years

Shore Platforms in the Algarve (South Portugal) Rocky Coast, an Inheritance of the Last Interglacial Stage?

Shore platforms, notches, and marine caves are common yet distinctive morphological features along the southern coast of Portugal. The central Algarve rocky coast has provided a favorable setting in which to understand the processes contributing to shore platform development. This is because the morphology and characteristics of the features vary along the coast, as do several factors implicated in their development such as wave climate (including wave direction and frequency), seabed morphology and depth, bedrock lithology, karstification and geological structure

Does the glacial/interglacial sea-level changes modulate the atmospheric CO2 variations?

It is postulated the rate of the terrestrial organic carbon (OC) retention around the moving ocean/continent interface is strongly affected by the sea-level

Algarve: a study case for global vs regional climatic changes in mid latitude estuaries during the Holocene

Located at the extreme southwestern end of the Iberian Peninsula, in the South of Portugal, the Algarve province is bordered to the north by the Alentejo province, to the east by the Guadiana River, and to the west and south by the Atlantic Ocean. Its coastal region can be divided into two different sectors: the eastern sector, which is mainly made of barrier island and lagoon system named the Ria Formosa, and the western sector mainly represented by clastic and carbonated cliffs. In each sector, we sampled long and short sedimentary cores (ca. 30m and 3m, respectively) in two different estuaries. Therefore, the different sedimentary records obtained from the four estuaries should permit to identify global vs. west-eastern regional climatic changes through the observation of several proxies. Two of these proxies are sediment color and magnetic susceptibility, which have been acquired every five centimeters along core depth, using the Colortron II spectrophotometer and SM-20 magneto-susceptometer, respectively. Sediment surfaces of short cores were also digitized using the Mustek 1200 A3 PRO Scanner. Furthermore, short cores have been sampled every five centimeters along depth in order to analyze the sediment for its major and minor elements content, its organic carbon content, and its granulometry and mineralogy. Some shell fragments have also been sampled and sent for radiocarbon radiometry or AMS dating, allowing therefore constructing some absolute chronologies for the several cores. Some relative chronologies based on digital color profiles are also being used in order to correlate sedimentary sequences between cores. All the cores are mainly composed of clay, with the existence of soil horizons at the top of the cores and frequent sand layers towards their base. Several element profiles along depths are compared, namely those regarding Sr, Ca, F, Ba, Al and Ti, as well as their ratios. First results indicate that geochemical and color data allow to identify similar sequences from west to east probably related to major climate episodes. Although, pronounced differences in mineralogy and accumulation rates from on site to another are probably due to differences, respectively, in the geochemistry of the drainage basin substratum and in the flow rate of the rivers, and therefore to local precipitation. We acknowledge FEDER and OE that financed this study through the Portuguese Foundation for Science and Technology (FCT) (POCTI/CTA/39733/2001)

Influência da integridade dos frutos de taperebá (Spondias mombin L.) in natura na qualidade da polpa congelada.

Encontrado na região Amazônica o taperebá é um fruto amplamente consumido, em função do sabor agradável, boa composição nutricional e presença de carotenoides. A comercialização como polpa congelada é a forma de beneficiamento mais usual no Brasil. A polpa do fruto é revestida por uma casca fina, facilmente rompida por choque mecânico, o tornando muito perecível. A coleta dos frutos na Amazônica é feita de forma manual, quando maduros se desprendem das árvores (altura de 20 a 30 metros), sendo então coletados no solo ou em telas de proteção. Tal prática resulta na perda de integridade da maioria dos frutos, o que torna mais rápida a deterioração dos mesmos. Entretanto, não há registros científicos relacionando a qualidade da polpa com a integridade dos frutos. Desta forma, o objetivo do trabalho foi avaliar esta influência, realizando a caracterização físico-química, estudos de compostos bioativos e análise microbiológica. Resultados mostraram que a polpa obtida através de frutos mais íntegros apresentou maiores teores de compostos fenólicos, vitamina C, sólidos solúveis e açúcares totais, podendo indicar que os frutos batidos possivelmente sofreram ligeiro processo fermentativo. Análises microbiológicas apresentaram contagens de bactérias e bolores e leveduras superiores, além da detecção de coliformes, inclusive fecais. Tais resultados reforçam a necessidade de técnicas mais apropriadas de coleta e da prática de pasteurização para polpa, visando a qualidade do produto final