The “Serras de Aire e Candeeiros” Natural Park, in the Centre of Portugal, are mostly formed by limestone formations of the Middle Jurassic. Among the plant species located in this Protected Area, there are seven endemic species included in Annex II and/or IV of CEE/92/43 Directive by their rarity: Arabis sadina, Coincya cintrana, Iberis procumbens subsp. microcarpa, Juncus valvatus, Narcissus calcicola, Saxifraga cintrana and Silene longicilia. Other noteworthy plant species occurring in these limestone formations, although not included in any of the CEE/92/43 Directive annexes, are numerous orchid species and also Anthyllis vulneraria subsp. lusitanica, Crambe hispanica, Cytinus ruber, Dianthus cintranus subsp. barbatus, Jonopsidium abulense, Inula montana, Koeleria vallesiana, Orobanche latisquama, Scabiosa turolensis, Serratula baetica subsp. lusitanica, Serratula estremadurensis, and Teucrium chamaedrys, most of them of rare occurrence in Portugal. The vegetation of these hills, in its ridge line, consists of a mosaic of more or less degraded communities of the holm forest Lonicero implexae- Quercetum rotundifoliae. In the valleys and foothills of Serra dos Candeeiros, reaching as far as Minde, the Portuguese oak forest Arisaro-Quercetum broteroi dominates. In the last years, we verify the expansion of the arborescent matorral with the consequent decrease of grasslands as a result of the sucessional dynamics. In this paper a brief review on biogeography and bioclimatology of the Portuguese Divisory Sector is presented. The vegetation of the places visited during the Geobotanical excursion” is also described, including new plant communities recognized in this Sector. Three new associations are proposed: Oenantho crocatae- Quercetum pyrenaicae (Populenion albae, Populion albae, Populetalia albae, Salici purpureae-Populetea albae), Trifolio pratensis-Phalaridetum coerulescentis and Arabido lusitanicae-Hordeetum bulbosae (Gaudinio verticolae-Hordeion bulbosae, Holoschoenetalia, Molinio-Arrhenatheretea).

Speleothems are secondary cave deposits formed in karst environments through the precipitation of calcium carbonate (CaCO3) and are considered excellent recorders of past climates and Earth’s magnetic field (EMF) variations. Magnetic minerals inherited from the surface soils (of a lithogenic or pedogenic origin) are transported into the cave and are further incorporated on the surface of the stalagmite by the dripping waters. During their deposition on the calcite layers, these magnetic minerals are orientated according to the direction of the EMF, resulting in the acquisition of a detrital remanent magnetization. In addition, the nature, concentration, and grain size of these magnetic minerals are controlled by climate and environmental factors acting on the soils, such as vegetation, precipitation, moisture, and temperature. Therefore, rock magnetic properties of stalagmites can be used as reliable paleoclimatic and paleoenvironmental proxies. Here I studied the paleomagnetism, the rock magnetism, and the stable isotope composition of a stalagmite (labeled GC-III) from the Cerâmica Cave, located in Ansião, Sicó Massif, central mainland Portugal, together with the analysis of as cave and soil sediments, and host rock (carbonates) samples. The paleomagnetic approach is based on the alternating field demagnetization and subsequent measurement of the natural remanent magnetization to isolate the characteristic magnetic component. The magnetic mineralogy is investigated by the analysis of Isothermal Remanent Magnetization (IRM) and Anhysteretic Remanent Magnetization (ARM) curves, hysteresis curves, and First-Order Reversal Curves (FORC) diagrams. Carbon and oxygen isotope composition was measured to discuss the potential link of the magnetic properties with environmental and climate variations. Results show that the stalagmite recorded reliable and robust paleomagnetic directions, close to the direction of the present-day Geomagnetic field in Portugal. However, low uranium content and high content of detrital thorium hampered the precise determination of the age of the magnetization. Based on the comparison of the virtual geomagnetic pole (VGP) calculated for the GC-III stalagmites with the GGFSS70 VGP’s model, an age of 30-34 kyr BP is proposed for the GC-III stalagmite. The magnetic mineralogy of the GC-III stalagmite, the soil, the cave sediments, and the host rock are represented by the association of maghemite/magnetite, hematite, and goethite, in different proportions and grain sizes. In the case of the low-coercive component (maghemite/magnetite), the values of kARM/IRM and the median destructive field (MDF) of ARM of the different stalagmite samples show similar values, close to the pedogenic and/or extracellular magnetite, suggesting a homogenous population of magnetic grains in term of coercivity and grain size. The kARM/IRM and MDF of ARM of the host carbonate plot in eolian magnetite, whereas cave sediment and surface soils have lower and more scattered kARM/IRM and MDF of ARM values but are still close to the pedogenic and/or extracellular magnetite area. Dispersion parameters estimated based on the unmixing of IRM curves are similar between stalagmite, cave, and soil sediments, whereas host rock samples have higher dispersion parameters. This suggests that the magnetite populations contained in the stalagmite are inherited from the surface soils rather than from the host rock. The gradual increase in hematite contribution in the total IRM intensity from the surface soil to the stalagmite observed in the unmixed IRM curves suggests that hematite may have precipitated in the stalagmite posteriorly to the calcite growth or that the deposition of higher amounts of hematite relative to magnetite result from a process of filtering and sorting by a selective transport. A moderate negative correlation between carbon and oxygen isotopes with magnetic susceptibility and IRM intensity suggests that the concentration of magnetic particles deposited in the stalagmite is controlled by rainfall and vegetation cover. These results provide promising insights for future paleomagnetic and paleoclimate studies of the Cerâmica cave.

ABSTRACT Satellite remote sensing systems are widely used in environmental studies for providing regional scale analyses with high temporal resolution. On the other hand, when local small scale spatial studies based on very high resolution data at specific moments are involved, unmanned aerial vehicles have been alternatively adopted. The present case study aimed to carry out the morphometric analysis and quantify the soil loss in two sinkholes located in Oxisol on carbonate rocks of the Paranoá Group, in an agricultural area of Niquelândia, Goiás state, Brazil, using unmanned aerial vehicle, in two periods. From the analyzed satellite images, it was estimated that the emergence period of the sinkholes was between December 2018 and April 2019. Based on the aerial survey carried out, 35.53 m2 of eroded area and 236.89 metric tons of soil loss were observed for the sinkhole 1, as well 299.96 m2 of area and 663.47 metric tons of loss in the first period and 961.66 m2 of area and 4,241.68 metric tons of loss after six months for the sinkhole 2.

With the objective to analyze the hydrological processes and the water balance, a simplified water balance method and the modified Penman formula were applied to the Ribeirão da Onça river catchment in Colombo city, Paraná State. For the analysis, the data obtained during the monitoring period from 1997 to 2000 were utilized. The results showed that the values of the real evapotranspiration estimated by the method of the simplified water balance were negative for the certain periods and for other period sometimes more than those of the potential evapotranspiration estimated by the modified Penman formula. It implied the existence of significant groundwater recharge from other catchments to the study area, and indicates that the simplified water balance method was not suitable for the hydrological study of this karst catchment. The value of the groundwater recharge received by this catchment was estimated as 554 mm/year for the analysis period.

It is estimated that the Brazilian karst areas sum about 200.000 km2. The caves, one of the main components of karst, are important windows into the biological studies on hypogean environments. In Rio Grande do Norte are known 563 caves, and 476 of them are in the municipalities of Baraúna, Felipe Guerra, Governador Dix-Sept Rosado, Apodi and Mossoró, the Western region of the State. However, like in the rest of the country, the cave fauna of the State is still poorly understood. This study used data from invertebrates harvested in 47 caves and aimed to analyze the effect of environmental change between the dry and rainy seasons in the communities of cave invertebrates, characterize these communities and evaluate the relationships between morphological and biotic variables of the caves and surroundings, and to define priority areas for conservation of cave environments of the study area from biotic parameters. Strong effects were found in the community structure of cave invertebrates due environmental changes between seasons, with values of total richness, abundance, diversity and ecological complexity significantly higher in the rainy season. It was possible to assess how the morphology of the cave and the external environment variables affect the biotic system, so that the variety of resources, forest cover in the vicinity, the area of the cave and its entrance were the variables that best explained the structure communities of cave invertebrates in the region. High values of total richness of invertebrates (36,62 ± 14,04 spp / cave) and troglomorphic species (61 species, mean 1,77 ± 2,34 spp / cave) were found and, given the biological relevance in the context of the area national and the imminent anthropogenic pressures existing, we defined four priority areas for actions aiming cave biodiversity conservation in the region.

O estudo concentra-se na região do Mato Grande, no estado do Rio Grande do Norte, território que abrange uma área de 5.986,20 km² e é constituído por 16 municípios. Esta região é objeto de estudo de futuras instalações de aterros sanitários, propostas pelo Plano Estadual de Gestão Integrada de Resíduos Sólidos (PEGIRS), que será contemplada com uma infraestrutura desta natureza. Ao se tratar dessa infraestrutura, um problema de elevada relevância em sua implantação refere-se à escolha de uma área para locação, existindo diversas metodologias que auxiliam essa tomada de decisão. Uma das metodologias aplicadas para avaliação de áreas que receberão a infraestrutura de aterros sanitários ou melhorar o julgamento de aterros já existentes é do Índice de Qualidade de Aterro de Resíduos (IQR). No entanto, uma análise aprofundada a respeito da aplicabilidade dessa metodologia, na localização ou avaliação de aterros sanitários em terrenos cársticos, indica a necessidade do uso de variáveis que contemplem as características próprias do meio cárstico. Sendo assim, este estudo pretende propor novas variáveis para o Índice de Qualidade de Aterros Sanitários (IQR) que considere as características e peculiaridades desse ambiente e, dessa forma, possa contribuir na identificação de técnicas e métodos destinados a um eficiente controle ambiental, assim como proporcionar segurança à própria instalação de uma infraestrutura dessa natureza.

Work carried out in 1988 at the cave of Igrejinha dos Soidos under the direction of L.G. Straus allowed the identification of an occupation that can be today attributed to the end of the Bronze Age (c. 1400 BC?), placing this site among the few non-funerary contexts of this time period known in the Algarve. In addition to characteristic pottery (flat bases, burnished surfaces), including cheese strainers, there is also a diversified faunal assemblage attesting a pastoral economy (sheep / goat and cattle).

INTRODUCTION Percolating water through organically enriched soil, raises the water pCO2 promoting an increase in carbonates dissolution. Following subaerial exposure, the water-atmosphere interaction, leads to an oversaturation of water CaCO3 and precipitation (PENTECOST, 2005; CHAFTEZ & FOLK, 1984). This precipitation can be inorganic, biologic or both (PEDLEY, 2009). The tufa facies presented in this work, follow GUERREIRO et alii (2010) and PEDLEY (1990) and the accumulation models follow PEDLEY (2009). In Central and Western Algarve over de Mesozoic limestone substrate, there are many tufa outcrops, with main outcrops occurring along the streams of Alte, Mercês, Cadouço, Rio Seco and Asseca. Algarve is the southernmost Portuguese region in the Iberian range, developed in three main geomorphological settings (FEIO, 1952). In the north, the mountainous area is mainly composed by Carboniferous schist and greywacke, and a Late Cretaceous intrusive massif in the west. In the south, develops the meridional Meso-Cenozoic Algarve basin, composed by the Triassic and Jurassic lithologies known as Barrocal with Cretaceous and Cenozoic sediments and the Littoral with Cenozoic topographically lower and eroded by the shore realm. HYDROLOGICAL SYSTEM The Algibre flexure is the main geomorphological feature in the area, where the karst is well developed as aquifer’s recharge area (ALMEIDA, 1985). The highest hills (350 to 380 m) are bare and soddy karst plain areas, where surface runoff is very low (e.g. Cabeça Gorda and Rocha). Lower colluvial areas have also low runoff conditions, because most are also low gradients (< 3°) and some have dolines and sinks (e.g. Campina dos Galegos or Rossinas). Discharge areas are located on the North and the South, but in different settings. Discharge to Mercês basin (North) is controlled by impermeable Triassic lithologies along high gradient slopes. All springs are intermittent and discharge is linked to the Mediterranean climate wet season. In the South, the discharge occurs along low gradient streams like Cadouço or São Lourenço. Different discharge settings result in different deposition systems as suggested in PEDLEY (2009). Fig. 1 PERCHED SPRINGLINE TUFA Springs in the Mercês basin are commonly perched and in low runoff karst, enhancing the development of perched springline model, where Pedley (1990) suggested proximal and distal deposits. Mature proximal deposits have wedge morphology with fan-shape, shaping low gradient terrace with a slow braided flow, sometimes with some ponds. In this area only the Olho de Paris can be classified as mature, with a 300 m long and wide, one small pond next to spring and many channels that spread from the old anthropic bank. High gradient at downstream edge enhance the sedimentation on cascades, producing moss curtains (subvertical moss laminar bioherm) intercalated by other bioherms and phytoclastic tufa on small pools and short low gradient channels where the upper macrophytes detritus (stems, fruits and leaves) accumulate leading to the development of tufa microdams and decimeter pools. Due to the high permeability in these systems, sometimes dissolution structures are present (ORDOÑEZ & GARCÍA DEL CURA, 1983). Decimeter scale holes in Penedos A. are covered by syngenetic speleothems and flowstones, however, there could have been a former hollow in the waterfall deposits now partially destroyed. Distal deposits in the above mentioned model are mainly composed by phytoclastic tufa and locally bioherm tufa developed on channels. However, in this model low gradient alluvial deposits exist downstream. Not only Olho de Paris but also Penedos Altos outcrops are followed by important stream sediments fed by the turbidite formations in the surrounding mountainous areas, with the high energy flow destroying the most recently deposited tufa. There are few situations where gravel and cobble is strongly cemented on modern stream, as in the case of the downstream of Olho de Paris or some strata from ancient accumulations. There are other incrusting springs in the area, but the low discharge related to the geomorphological or hydrogeological settings prevent the outcrops maintenance. FLUVIAL TUFA In the southern low-gradient streams, fluvial models develop. The main modern features in the area are the waterfalls up to 5 m and channels, where the main facies are macrophytes, moss and other lamellar bioherm tufa and oncoids. This is an intermediate model for braided fluvial model and barrage model, where valleys are incised but incipient discharge associated to the Mediterranean climate and small aquifer produce a cascade model. In the studied case lakes are absent and few small pools exist due to the low sedimentation. The São Lourenço stream outcrop is developed in a valley floor struggle, where ancient pebble conglomerates with massive carbonate cement are horizontally followed by curtain moss and algae laminar tufas and some low energy pool deposits. Despite the modern deposition, both valleys are currently incised in older tufa deposits which are present on river banks and terraces. The ancient structures show the same facies associations as the modern ones, with some tufa clasts and unconformities interlayered in some sequences of sedimentation. CONCLUSION Algibre flexure is the main geomorphological structure in the area, which include the recharge area feeding the springs on the northern and southern slopes. Geomorphological conditions result in distinct tufa structures, especially when considering slopes gradient. In the northern high gradient slopes, perched springline models are predominant. In low gradient streams like Cadouço and São Lourenço, deposits along the streams can occur. However, in this situation we don’t know lacustrine deposits like other Mediterranean outcrops despite the presence of modern and ancient waterfalls or just stream deposits. Spring regime with long discharges allows the development of bigger and more suitable structures to model the systems, especially when discharge extends to the warmer months like May or June. ACKNOWLEDGEMENTS Work financed by Fundação para a Ciência e Tecnologia Ph.D. grant SFRH/BD/62323/2009. REFERENCES ALMEIDA, C. (1985) – Hidrogeologia do Algarve Central. Ph.D. thesis in Geol. Faculdade de Ciências da U. de Lisboa. CHAFTEZ, H., FOLK, R. (1984) – Travertines: depositional morphology and the bacterially constructed constituents. J. Sed. Petr., 54 (1), 289-316. FEIO, M. (1952) – A Evolução do Relevo do Baixo Alentejo e Algarve. Ph.D Thesis in Geogr. F. de Letras da U. de Lisboa. GUERREIRO, P.; CUNHA, L.; RIBEIRO, C.; CANDEIAS, A. (2010) – Os tufos calcários das áreas de Estoi, Loulé e ribeira das Mercês (Algarve, Portugal): caracterização e significado paleoambiental. In: e-Terra, 21 (7). [http://e-terra.geopor.pt]. 4 pp. ORDOÑEZ, S.; GARCÍA DEL CURA, M. (1983) – Recent and terciary fluvial carbonates in Central Spain. Spec. Publs. Int. Ass. Sed., 6, 485-497. PEDLEY, H.M. (1990) – Classification and environmental models of cool freshwater tufas. Sed. Geol., 68, 143-154. PEDLEY, H.M. (2009) – Tufas and travertines of the Mediterranean region: a testing ground for freshwater carbonate concepts and developments. Sedimentology, 56, 221-246. 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