Sapientia
UAlg Scientific Repository
About Sapientia
The SAPIENTIA repository gathers an exhaustive set of Algarve University's (UAlg) teachers and researchers scientific publications with an express goal of maximising its visibility, ensure easy and universal access and amelliorate the overall public impact of the university scientific endeavors, as well as the ongoing preservation of its memory.
Recent Submissions
A necrópole da gruta da Verdelha dos Ruivos (Vila Franca de Xira) e a génese do Complexo Campaniforme na região da foz do Tejo (Portugal)
Publication . Cardoso, João Luis; Leitão, M.; Ferreira, O. da Veiga; Zbyszewski, G.; North, C. T.; Norton, J.
The Verdelha dos Ruivos cave, located around 20 km NNE of Lisbon, is the only necropolis of the Bell Beaker Complex identified in Portugal to date in which it was possible to isolate in a stratigraphic sequence, single burials and reconstruct the original position of the corpses.
The cave was occasionally identified in 1973, during the inspection of a Cretaceous limestone quarry, whose exploration front sectioned the cavity, leaving only the distal part of it.
The excavation was carried out by a team from the Geological Service of Portugal led by O. da Veiga Ferreira, which included a medicine doctor, which constituted an obvious added value for characterizing the composition of the population and knowledge of the methods of inhumation used.
The small crypt that remained of the primitive natural cavity, whose brown filling contrasted with the color of the limestone, was completely emptied by an hardened carbonate breccia, with abundant limestone blocks, containing archaeological remains. The hardness of this very consolidated filling made it difficult to carry out the excavation, which began in October 1973 and ended only in May 1974.
Three main levels were identified, consisting of successive individual tombs in dorsal decubitus, on the left or right side, with the body retracted, in the uterine position. It was possible to identify the position of 11 graves, some related with limestone slabs, which constituted the base or covering of the graves.
The archaeological remains included all the items considered characteristic of Bell Beaker Complex: sperm whale tooth buttons, gold spirals, a Palmela point, a fragment of a wristguard and ceramics, of which the decorated ones belong exclusively to the Bell Beker Complex, which leads to the conclusion that the funerary use of the cave is exclusively from a community related to this cultural “circle”.
The absolute dating carried out allowed us to place the beginning of this necropolis between 2700 and 2600 years BC, extending into the second half of the 3rd millennium BC. These results are consistent with the antiquity of the emergence of the Bell Beaker Complex in the Tagus estuary region, as was demonstrated by the results obtained at the prehistoric settlement of Leceia, located approximately 30 km to the SW, a reality that will be also valued and discussed.
Evolution of west‐east contrast in the subarctic pacific gyre during the plio‐pleistocene based on palynological evidence at ODP sites 882 and 887
Publication . Zorzi, Coralie; Vernal, A. de
Fragmentary and contradictory evidence prevents a clear understanding of the possible role of the North Pacific Ocean surface on the ice-sheet evolution. New palynological data encompassing the Pliocene and Pleistocene at Ocean Drilling Program Site 882 in the northwest Pacific document sea-surface conditions from dinoflagellate cysts in addition to atmospheric trajectories from pollen grains and spores. The comparison of the Site 882 record with that of Site 887 from the northeast Pacific also permits documenting West to East contrasts across the subarctic North Pacific. The dinocyst assemblages at the two sites indicate strong temperature contrasts until 4.2 Ma, with much warmer conditions in the East. From 4.2 to 3.6 Ma, dinocyst assemblages of both sites are characterized by alternated dominance of the extinct taxa Habibacysta tectata and Impagidinium detroitense suggesting homogenous and cool conditions across the subarctic Pacific gyre. A major transition is recorded in the palynological assemblages at Site 882 around 2.7 Ma. It is marked by the highest occurrence of Habibacysta tectata and high percentages of Filisphaera microornata additionally to thermophilic taxa. Dinocyst record indicates high seasonality and warmer surface conditions due to reinforced stratification, which support the hypothesis of high evaporation at the origin of atmospheric moisture supply to high latitudes. During the last 1.2 Ma, the increase of Operculodinium centrocarpum relative to Nematosphaeropsis labyrinthus is tentatively interpreted as a reinforced influence of the subtropical waters. Hence, we suggest that the warm surface ocean fostered the inception and growth of northwestern North American ice-sheets during the Pliocene and Pleistocene.
Dinocyst assemblages in the subarctic Pacific record changes in temperature and productivity through the Plio-Pleistocene The major transitions reflect halocline onset at 2.7 Ma and a major cooling at 1.7 Ma Subarctic ocean temperature and Westerlies migration may have affected northward moisture supply and ice-sheet growth over North America.
Carbonate microfacies reveal how Asturian shell middens formed in the mesolithic
Publication . Lucas Antunes Simões, Carlos Duarte; Iriarte; Eneko; Gutiérrez-Zugasti; Igor; Arias, Pablo
The littoral platform of eastern Asturias (northern Spain) is a coastal karst modeled by the sea. During the Early Holocene, this landscape was exploited by successfully coastal-adapted hunter-gatherers. Intense coastal foraging resulted in accumulation of large amounts of shellfish in numerous karstic rockshelters. A century ago, the Count of Vega del Sella established the post-Paleolithic age of the Asturian shell middens, carbonate-cemented deposits hanging from the walls of karstic cavities. He argued that these were remnants from past shell accumulations filling up completely the rockshelters, as result of direct waste disposal, while the occupations occurred outside. Our geoarchaeological approach tested this long-lasting site-formation model with micromorphology and carbonate microfacies analysis of two sites: El Alloru and El Mazo. Novel outcomes are: 1) the carbonate cements correspond to calcareous tufa resulting from spring activity; 2) the deposits show a stratigraphic framework related to successive phases of debris accumulations and stasis; 3) tufa formation and accumulation of anthropogenic debris are syn-depositional; 4) biogenic and diagenetic cements reveal phreatic conditions. All these contradict a priori expectations from Vega del Sella's widely accepted model of anthropogenic mound constructions preserved in the currently cemented deposits. Microcontextual evidence suggest that shells were likely processed and produced also inside the rockshelters, which might have been used as occupation spaces as well instead of just for waste disposal, while the analyses exterior deposits at El Alloru also present occupational signs. This study also supports further evidence for higher water-table levels in the early Holocene at regional level, despite most caves show no signs of spring activity today.
Anthropogenic microparticles accumulation in small-bodied seagrass meadows: the case of tropical estuarine species in Brazil
Publication . Souza, Ana M. C.; Ferreira, Guilherme V. B.; Barrena de los Santos, Carmen; Frédou, Flávia L.; Magalhães, Karine M.
Seagrass meadows have recently been highlighted as potential hotspots for microplastic and anthropogenic microparticles (APs). This study assessed AP accumulation in shallow sediments vegetated by small-bodied seagrass species (Halodule wrightii, Halophila decipiens, and H. baillonii) and in the adjacent unvegetated area in a tropical estuary on the East Coast of South America, Brazil, over the seasonal cycle. Anthropogenic microparticles were detected in 80 % of the samples, with a mean abundance of 142 +/- 140 particles kg(-1) dw (N = 80). Particles were predominantly blue (51 %), fiber (73 %), and smaller than 1 mm (80 %). We observed that seagrass sediments retained APs, although no significant variation was observed between seagrass and the unvegetated area, nor between the dry and rainy seasons. A positive correlation was found between sediment grain size and AP abundance. This study represents the first record of AP contamination in seagrasses from the Tropical Southwestern Atlantic bioregion.
Experimental determination of effective concentration ratio for two different designs of concentrating solar cookers
Publication . Sagade, Atul A.; Apaolaza-Pagoaga, Xabier; Ruivo, Celestino; Carrillo-Andrés, Antonio
The concentration ratio is most influential characteristic of the solar concentrators, impacting on its opto-thermal performance. Hence, concentration ratio's, realistic and quantificable measurement is essential. Therefore, this paper reveals the usefulness of the determination of an effective concentration ratio (Ceff) for a satellite antenna dish and Parvati concentrating solar cookers. Open and closed reflector open sun cooling tests were performed to determine the cooker opto-thermal ratio (COR). A thin black cloth used over each reflector neutralizes the effect of the reflection of solar radiation in the closed reflector tests. Subsequently, the COR values for these two types of tests enables the determination of the Ceff. Some corrective actions are suggested to eliminate the errors occurring during open reflector open sun cooling tests. Results show that the values of the Ceff for the satellite dish and Parvati cookers are 7.34 and 3.61, respectively. The determination of Ceff values enables commenting on its effective and realistic value, the role of the concentrator's reflecting surface in the concentration effect, and the degradation of the reflector surface. Thus, the Ceff is a practical indicator for assessing the impact of optical characteristics of the reflecting surface of the CSCs.