Soils of the Jurassic formations in the central Algarve; their occurrence, distribution, genesis and site qualities

In the central Algarve different soils have developed dependent on petrography of the parent material, slope position and recent erosion. The general patterns of occurence and distribution of different soils are described. The age of an eutric Nitosol is estimated and the relation between the soil and the parent material is investigated. Some different soils are described as examples with their chemical and physical properties. The water budget of soils is described in general with considerations concerning ground water recharge and run-off as well as in dependence of climate and of different site conditions.

Microfacies studies of carbonate rocks from Jurassic outcrops in the north of Faro, Southern Portugal

The Middle and Upper Jurassique limestones investigated were sub-divided into nine microfacies (MF) types. The firsts four represent Bathonian sediments with shallow water characteristics typical for carbonate platforms. They are comparable with Wilson's facies zones 6 to 8. Reef and reef debris, near-shore clastic-dominated limestones are not present. These MF-types are reiterated several times without cyclicity. The vertical development of the differentiated facies units indicates a close interfingering. The microfacies data are typical of inter to shallow subtidal environments; both authigenous quartz and low faunal and floral diversity of several layers point to temporary restricted conditions. The occurrence of Dictyoconus cayeuxi LUCAS and Callovian ammonites from the above lying strata argue for a Bathonian age. The MF-types 5-9 (Oxfordian-Kimmeridgian) show completely different sedimentation conditions. Fully marine nearshore recifal limestones alternate with pelagic sediments formed at deeper shelf areas. The pelagic micritic limestones of Oxfordian age are characterized by allodapic intercalations whereas the Oxfordian/Kimmeridgian limestones with tuberolithic fabrics often show intensive silifications. Only initial patch reef growth-stages were reached during the development of the Oxfordian and Kimmeridgian shallow water limestones.

Eggs and eggshells of Crocodylomorpha from the Upper Jurassic of Portugal

Crocodylomorph eggs are relatively poorly known in the fossil record when compared with skeletal remains, which are found all over the world, or when compared with dinosaur eggs. Herein are described crocodiloid eggshells from the Upper Jurassic Lourinhã Formation of Portugal, recovered from five sites: Cambelas (clutch), Casal da Rola, Peralta (eggshell fragments), and Paimogo North and South (three partial crushed eggs and eggshell fragments). The clutch of Cambelas, composed of 13 eggs, is the only sample not found in association with dinosaur eggshells. Morphological characters of the eggshells described herein, such as shell units and microstructure, are consistent with the crocodiloid morphotype. As such, this material is assigned to the oofamily Krokolithidae, making them the oldest known crocodylomorph eggs so far and the best record for eggs of non-crocodylian crocodylomorphs. Two new ootaxa are erected, Suchoolithus portucalensis oogen. et oosp. nov, for the clutch of Cambelas, and Krokolithes dinophilus, oosp. nov., for the remaining eggshells. The basic structure of crocodilian eggshells has remained stable since at least the Late Jurassic. Additionally, the findings suggest previously unknown biological associations with contemporary archosaurs, shedding light on the poorly understood egg morphology, reproduction strategies and paleobiology of crocodylomorphs during the Late Jurassic.

A reconnaissance study of Upper Jurassic sediments of the Lusitanian Basin

The Upper Jurassic evolution of the Lusitanian Basin is shown to be linked to the rifting phase which preceded the separation of Iberia and the Grand Banks. Structural controls on sedimentation include both NNE-SSW trending faults in the Hercynian basement, and contemporaneous movement of salt diapirs. At the beginning of Upper Oxfordian times, the entire basin had been levelled to within a few metres of sea level, so that the freshwater algal marsh and marginal marine facies of the Cabaços and Vale Verde Beds rest on Triassic to Callovian strata. In the latter part of the Upper Oxfordian. carbonate sedimentation continued, with fluctuating salinity lagoons in the north (Pholodomya protei Beds) separated from shallow open marine carbonates in the south (Montejunto Beds) by the Caldas da Rainha diapir-barrier island complex. The commencement of rifting is recorded in the Kimmeridgian by the sudden influx of terrigenous clastics (developed in both fluviatile and deltaic/submarine fan environments) and accelerated depositional rates in excess of 10cm/10 k.yrs in association with contemporaneous faulting along the SE margin of the Arruda sub-basin. The Caldas-Santa Cruz chain of diapiric structures continued to influence the distribution of carbonate and clastic sediments. In the Portlandian, a simpler facies pattern occurs, with fluviatile clastics interfingering to the south with shallow low energy carbonates.

New evidence of shared dinosaur across upper jurassic proto-North Atlantic: stegosaurus from Portugal

Naturwissenschaften 94,367–374

Upper Jurassic Hybodontidae (Selachii) from Lourinhã, Portugal

Hybodontidae teeth and spines from the Lourinha Formation, Sobral unit are described. These teeth and spines have been ascribed to the genus Hybodus and regarded as Hybodus cf. reticulatus.

Estudo Estratigráfico e Paleontológico do Jurássico do Algarve Ocidental

Algarve Province, Southern Portugal, corresponds in part to a meso-cenozoic basin running along the coast from Cabo S. Vicente to beyond Spanish border. Structurally it is a big monocline plunging southwards much deformed mainly by two East-West longitudinal flexures. Lithostratigraphical and chronostratigraphical studies dealt specially with Jurassic formations. This and the geological mapping of the post-Hercynian sedimentary formations allow us to define the following units: Triassic-Lower Liassic Arenitos de Silves (Silves sandstones sensu P. Choffat, pro parte) - At their base the Silves sandstones (0-150m) are represented mainly by cross-bedded red sandstones. This unit is Upper Triassic (Keuper) in age, on the evidence of some Brachiopoda. Complexo margo-carbonatado de Silves (Silves marl-limestone complex=Silves sandstones sensu P. Choffat, pro parte) (80-200m) overlies the preceding, it may be reported to the Upper Triassic-Hettangian. It consists of a thick pelite-marl-dolomite-limestone series with many intercalations of greenstones. Since no fossils were found it is not possible to conclude whether it is still Hettangian or if it does correspond, in the whole or in part, already to the Sinemurian. Liassic Dolomitos e calcários dolomíticos de Espiche (Espiche dolomite-rocks and dolomitic-limestones) - The usually massive and finely crystalline or saccharoidal dolomites and dolomitic-limestones are the toughest strata of the Algarve margin giving rise to several hills. Its thickness attains in certain points 60 metres at least. Based on geometry and on lithological similarities with the carbonated complex of the northern basin of Tagus river (Peniche, São Pedro de Muel, Quiaios), this formation can be accepted as Sinemurian in age. As it happens with the carbonated complex, here also the first dolomite beds are non-isochronal throughout the region; upper time-limit of the dolomitic facies is either Lower Carixian, Lower Toarcian or even Lower Dogger. The dolomitization is secondary but not much later than sedimentation. However, between Cabo S. Vicente-Vila do Bispo there is evidence of an even later secondary dolomitization related to the regional fault complex. Calcário dolomítico com nódulos de silex da praia de Belixe (Belixe beach dolomitic-limestone with silex nodules) (50-55m) - Ascribed to Lower or Middle Carixian on the basis of Platypleuroceras sp., Metaderoceras sp. nov. and M. gr. Venarense. Calcário cristalino compacto com Protogrammoceras, Fuciniceras e ? Argutarpites de Belixe (Belixe compact crystalline limestone with Protogrammoceras, Fuciniceras and ? Argutarpites) (30m) - Ascribed to Lower Domerian. Middle and Upper Domerian are indicated but by a single specimen of ? Argutarpites. Calcários margosos e margas com Dactylioceras semicelatum e Harpoceratídeos de Armação Nova (Armação Nova marly limestones and marls with D. semicelatum and Harpoceratidae) (25m) -Ascribed to Lower Toarcian. Middle and Upper Toarcian formations are not known in the Algarve. Dogger Calcários oolíticos, c. corálicos, c. pisolíticos, c. calciclásticos, c. dolomíticos e dolomitos de Almadena (Almadena oolitic-limestones, coral-reef-limestones, pisolite-limestones, limeclastic-limestones, dolomitic-limestones and dolomite-rocks) (more than 50 metres), with lagoonal facies. Ascribed to Aalenian-Bathonian-? Callovian. Margas acinzentadas e calcários detríticos com Zoophycos da praia de Mareta (Mareta beach greyish marls and detritical limestones with Zoophycos) (40m) - Pelagic transreef facies with Upper Bajocian and Bathonian ammonites. Calcários margosos e margas da praia de Mareta (Mareta beach pelagic marly-limestones and marls) (110m) - Ascribed to the Callovian on its ammonites. Malm Near Cabo S. Vicente and Sagres the first Upper Jurassic level consists of a yellowish-brown nodular, compact, locally phosphated and ferruginous, sometimes conglomeratic, marly limestone (0,35-1,50m) containing a rich macrofauna, which includes: 1) Callovian forms unknown at Lower Oxfordian; 2) Upper Callovian forms that still survived in Lower and Middle Oxfordian; 3) Lower Oxfordian forms (Mariae and Cordatum Zones); 4) Lower and Middle Oxfordian forms (Mariae to Plicatilis Zone); 5) Middle Oxfordian forms (plicatilis Zone), and some ones appearing in Middle Oxfordian. This condensed deposit is therefore dated from Middle Oxfordian (Plicatilis Zone). The other Upper Jurassic lithostratigraphical units were also mapped but their detailed study is not presented in this work. Correlations between lithostratigraphical and chronostratigraphical scales from P. Choffat, J. Pratsch, C. Palain and from the author are stated. Further correlations are attempted between zonc scales of Carixian-Lower Toarcian and Upper Bajocian-Middle Oxfordian of France, Spain (Asturias, Iberian and Betic Chains), Argel (Orania) and Portugal (northern Tagus basin and Algarve). The study of pyritous fossil assemblages common in Upper Bathonian-Lower Callovian marly levels of the praia da Mareta seems to suggest that these sediments were deposited in a bay or in an almost closed coastal re-entrance virtually without deep water circulation. Although such conditions may occur at any depth one may suppose that these ones actually correspond to an infralittoral neritic environment. The thaphocoenosis collected there are almost entirely composed of nektonic (ammonites, Belemnites) and planktonic (Bositra) faunas. The sedentary (crinoids, brachiopods) or free (sea-urchins, gastropods) epibenthonic forms are very scarce; endobenthonic forms are not known. The palaeontological study of all Nautiloids and Ammonoids of the Liassic and Dogger is presented (except Kosmoceratidae and Perisphinctaceae). Among the thirty one taxa dealt with, one is new (Metaderoceras sp. nov.) and the great majority of the others has been identified for the first time in Algarve. Some others have never been reported before in Portuguese formations. The evolution, during Jurassic times, of the sedimentary basins of the Portuguese plate margin is described. The absence of Cephalopods in the very extensive marly and dolomitic limestones, partly marine, suggests that, during Lower Liassic, palaeogeography underwent no great changes. Dolomitic-limestone with silex nodules from Cabo S. Vicente contain the first ammonites recorded at the base of the Middle Liassic. This facies, although very common in Tethys, is unknown north of the Tagus. The faunal assemblage has a mediterranean to submediterranean character. Comparisons between faunal assemblage" from Algarve with the ones known north of the Tagus show that communications between Boreal Europe and Tethys, virtually non-existent during Lower and Middle Carixian, became very easy during Lower Domerian. In earlier Pliensbachian times two distinct seas were adjacent to the Iberian plate. One, an epicontinental sea with a tethyan fauna, extended southwards from the Meseta margin. Another, was a boreal sea; during its transgressive episodes boreal faunas attained into the basin north of the Tagus. During Middle Carixian and Lower Domerian, owing to simultaneous transgressions, these two seas joined together allowing faunal exchanges along the epicontinental areas which limited the emerging hercynian chains belts. During Liassic, the Algarve belonged undoubtedly to the tethyan submediterranean province. The area north of the Tagus, on the contrary, was a complex realm where subboreal and tethyan affinities alternatively prevailed. In the Algarve the first Middle Jurassic deposits do frequently show lateral thickness reductions as well as unconformities contemporaneous with other generalized disturbances on the sedimentation processes in other parts of Europe. By this time, near Sagres, a barrier reef developed separating lagoonal or ante-reef facies from the transreef pelagic zone. The presence of tethyan fauna, the abundance of Phylloceratidae and the absence of boreal forms allow us to consider the Algarve basin as a submediterranean province. The presence of Callovian pelagic fossiliferous formations in the Loulé area shows that during Middle Jurassic the marl-limestone transreef sedimentation was not confined to the western Algarve. They would extend eastwards where they only can be seen in the core of some anticlines. This is due to the progressive sinking of the meso-cenozoic formations as we proceed towards the South of the Sagres-Algoz-Querença flexure. In the whole of the Peninsule, and as for the Middle Callovian, an important regression can be clearly recognized on the evidence of an erosion surface which strikes obliquely the Middle and Upper Callovian strata. The geographic boundaries of the different faunal provinces are not changed by the presence of many Kosmoceratidae in the phosphate nodules since they are but a minority in comparison with the tethyan forms. An abstract model can be constructed showing that in Western Europe the Kosmoceratidae may have migrated South and westwards through a channel of the sea that linked Paris basin to Poitou and Aquitaine. By migrating between the Iberian meseta and the Armorican massif this fauna reached northern Tagus basin at the beginning of Upper Callovian (Athleta Zone); this south and southwest bound migration would have proceeded, allowing such forms to reach Algarve basin only in latest Callovian times (Lamberti Zone). This migration means that during Middle Jurassic a widely spread North Atlantic sea would exist, flooding the western part of Portugal up to the Poitou.

Les Hipparion du Portugal

This paper is concerned with Hipparion from Ribatejo, Portugal, and with the stratigraphy of the Neogene series of this region. The first two chapters are an introduction and an historical review. Paleontological study includes both a revision of the specimens accounted by ROMAN (1907) and the description of new material. Two forms were recognized, an early H. cf. primigenium, lower Vallesian in age, NM 9 mammal unit (from Archino, Vila Nova da Rainha, Aveiras de Cima), and a more advanced H. primigenium cf. melendezi. Upper Vallesian, NM 10 (possibly lowermost Turolian, NM 11) (at Azambujeira and Marmeleira). A synthesis of Middle and Upper Miocene from Ribatejo is also presented. Levels with H. p. cf. melendezi are somewhat older than «Upper Pontian», as it was previously acknowledged, they attain at the best the lowermost Turolian (approximately corresponding to «Upper Pontian»). Even higher levels may be Turolian in age, though they are not yet accurately dated. Almost all the localities are shown (tableau 11) according to its stratigraphical position; age, correspondance to mammal units from NM 5 to NM 10 (and may be also from NM 11 to NM 12), and correlation with marine formations near Lisbon are also taken in account. The stratigraphical position of localities such as Póvoa de Santarém, Quinta do Marmelal, Pero Filho, Azambujeira (lower levels), and Fonte do Pinheiro was revised; the stratigraphical position of Marmeleira was ascertained. The localities so far known correspond to NM 5 (?), NM 6, NM 8, NM 9, NM 10 and possibly to NM II and NM 12. A new interpretation (M. T. ANTUNES) of localities with oysters from Ribatejo allows a better correlation with vertebrate localities. Relationships with Serravallian transgression seem well established. Only two localities, Vila Nova da Rainha and Foz do Alviela, may possibly be correlated to V-b division of Lisbon (Langhian) with «Hispanotherium fauna». All the other localities are younger than Serravallian oyster beds. Undirect correlation shows that NM 6 localities are somewhat younger than the apogee ef Serravallian transgression (corresponding approximately to Blow's N 11 to N 13 zones based on planctonic foraminifera).

Les Hipparion du Portugal

This paper is concerned with Hipparion from Ribatejo, Portugal, and with the stratigraphy of the Neogene series of this region. The first two chapters are an introduction and an historical review. Paleontological study includes both a revision of the specimens accounted by ROMAN (1907) and the description of new material. Two forms were recognized, an early H. cf. primigenium, lower Vallesian in age, NM 9 mammal unit (from Archino, Vila Nova da Rainha, Aveiras de Cima), and a more advanced H. primigenium cf. melendezi. Upper Vallesian, NM 10 (possibly lowermost Turolian, NM 11) (at Azambujeira and Marmeleira). A synthesis of Middle and Upper Miocene from Ribatejo is also presented. Levels with H. p. cf. melendezi are somewhat older than «Upper Pontian», as it was previously acknowledged, they attain at the best the lowermost Turolian (approximately corresponding to «Upper Pontian»). Even higher levels may be Turolian in age, though they are not yet accurately dated. Almost all the localities are shown (tableau 11) according to its stratigraphical position; age, correspondance to mammal units from NM 5 to NM 10 (and may be also from NM 11 to NM 12), and correlation with marine formations near Lisbon are also taken in account. The stratigraphical position of localities such as Póvoa de Santarém, Quinta do Marmelal, Pero Filho, Azambujeira (lower levels), and Fonte do Pinheiro was revised; the stratigraphical position of Marmeleira was ascertained. The localities so far known correspond to NM 5 (?), NM 6, NM 8, NM 9, NM 10 and possibly to NM II and NM 12. A new interpretation (M. T. ANTUNES) of localities with oysters from Ribatejo allows a better correlation with vertebrate localities. Relationships with Serravallian transgression seem well established. Only two localities, Vila Nova da Rainha and Foz do Alviela, may possibly be correlated to V-b division of Lisbon (Langhian) with «Hispanotherium fauna». All the other localities are younger than Serravallian oyster beds. Undirect correlation shows that NM 6 localities are somewhat younger than the apogee ef Serravallian transgression (corresponding approximately to Blow's N 11 to N 13 zones based on planctonic foraminifera).

Goldra: premier gisement karstique en Algarve, faune et industries

A bone breccia from Goldra, near Loulé, is studied. It corresponds to the infilling of a karst depression, consisting of: rather worn and probably transported dolomite pebbles at the bottom; accumulations of frequently burnt bone scraps, much broken and with acute edges (no transport), certainly debris of human food, suggesting habitat level (s); in association with the former, stone (flint, quartz, quartzite, graywacke) rather uncharacteristic artifacts that seem compatible with middle and upper Paleolithic, or with Epipaleolithic; and small mammal teeth and bones. Fauna includes an extinct species, Microtus brecciensis recognized for the first time in Portugal. It is not older than Riss-Wiirm interglacial, and may be of this age or later, maybe that of one of wurm's first interstades. Fauna points out to a varied landscape with open country and woods; and to a rather warm and dry temperate, or dry subtropical mediterranean climate. Climate differences should not be significant in comparison with the extant situation. The presence of the mammal species found so far is consistent with modern distribution.

Iberosuchus et pristichampsus, crocodilians de l’éocène données complémentaires, discussion, distribution stratigraphique

Two eocene ziphodont crocodillans (Ilberosuchus and Pristichampsus) are dealt with. Their distinction seems possible, even with isolated teeth. The association of both in some localities may account for some previous identification difficulties. Geographical and stratigraphical distribution indicated: for Pristichampsus from Germany to Spain, Cuisan to to Upper Lutetian; for Iberosuchus from France to Portugal, lower Lutetian to Bartonian and maybe Ludian.

Paleolítico médio e superior em Portugal: datas 14C, estado actual dos conhecimentos,síntese e duscussão

New radiocarbon measurements were obtained from middle and upper Paleolithic sites currently under research by the CEPUNL, in well defined stratigraphical situations. With other dates, they yield an approximative chronological global view. Measurement distribution in function of time does not seem to be an hazardous one. In the actual status of our knowledge, this distribution seems to fit in some assemblages: (a) 14000 to 15000 BP, Solutrean; (b) about 20 000 BP, Solutrean; (c) circa 25 000 BP, already Solutrean, and slightly older than 26 000 BP, still Mousterian; (d) between 29 000 and 31 000 BP, Mousterian. The persistance of Mousterian much later than its acknowledged upper limit at about 34 000 BP (and hence the survival of its neanderthalian authors) is demonstrated. For the first time it has been possible to ascertain the upper time limit of the marine 5-8 metres raised beach (Tyrrhenian III) at Serra da Arrábida, and also the age of archaeological sites without stone artifacts, or with uncharacteristic ones. The obtained measurements allow US to correlate localities and sedimentary units with last glaciation events. There seems to have been a distinct correlation between cave and shelter human occupation and events marked by the worsening of climate.

Paleolítico médio e superior em Portugal: datas 14C, estado actual dos conhecimentos, síntese e discussão

New radiocarbon measurements were obtained from middle and upper Paleolithic sites currendy under research by the CEPUNL, in well defined stratigraphical situations. With other dates, they yield an approximative chronological global view. Measurement dístribution in function of time does not seem to be an hazardous one. ln the actual status of our knowledge, this distribution seems to fit in some assemblages: (a) 14000 to 15000 BP, Solurrean ; (b) about 20 000 BP, Solurrean ; (e) area 25 000 BP, already Solurrean, and slightly older than 26 000 BP, still Mousterian ; (d) between 29 000 and 31 000 BP, Mousterian. The persistance of Mousterian much later than its acknowledged upper limit at about 34 000 BP (and hence the survival of its neanderthalian authors) is demonstrated. For the first time it has been possible to ascertain the upper time limit of the marine 5-8 metres raised beach (Tyrrhenian III) at Serra da Arrábida, and also the age of archaeological sires wirhout srone arrifacts, or with uncharacteristic ones. The obtained measurements allow us to correlate localities and sedimentary units with last glaciation events. There seems to have been a distinct correlation between cave and shelter human occupation and events marked by the worsening of climate.

Le gisement de Asseiceira, Portugal (Miocène supérieur) Données complémentaires sur Freiria de Rio Maior

A new upper Miocene locality at Asseiceira (Rio Maior), near the top of the "Calcários de Almoster e Santarém" unit (Almoster and Santarém limestones) is studied. Animal and plant fossils are described. Comparisons are drawn to other localities related to the same unit: Freiria and Azambujeira (middle and upper levels, both with large mammals). Small mammals from Asseiceira and Freiria point out to a rather old age amidst the upper Vallesian, MN 10 mammal-unit. This gives a fairly accurate datation for the "Calcários de Almoster e Santarém" and for the short time span of the corresponding sedimentation. Climate was warm and quite dry, with contrasting seasons and arid events. During upper Vallesian times, climate in Iberian Peninsula was varied but drier than in France, and specially so in the inner basins. However in Portugal and in Catalonia climate would he less different in comparison with that of the Rhône basin. Environmental evolution has been important: at Freiria and Azambujeira (middle level) there were mainly shallow lacustrine environments that received ressurgence waters from the nearby "Maciço calcário". Humid areas were closely surrounded by dense forests and these by broader and drier savanna or steppe areas. Still later, carbonate sedimentation ended. For some time there was still a river system with oxbows; humid areas probably were decreasing in favour of surrounding, rather dry environments. This study stressed the nced for revision of the geology of the region of Rio Maior and for a new geological mapping of that area. Environmental evolution has been important: at Freiria and Azambujeira (middle level) there were mainly shallow lacustrine environments that received ressurgence waters from the nearby "Maciço calcário".

Une succession de référence pour le Toarcien Moyen et Supérieur: les "Margas calcárias de São Gião" dans les environs de Cantanhede (sous-bassin nord lusitanien, Portugal)*

The geological sections studied at the São Gião sector (Cantanhede region) have allowed the establishment of a clear succession of ammonite associations during the Middle and Upper Toarcian (“Margas calcárias de São Gião” and “Calcários margosos de Póvoa da Lomba” Formations). The fossil collections were gathered over the last 40 years and, in spite of the apparent facies monotony, come from a thick and fossiliferous marly-limestone unit. The ammonite succession allows the establishment and/or verification of a certain number of biostratigraphical elements, of which are worthy of mention: – the tethyan character of the fauna from the Gradata to the Meneghinii Zones; this differentiation starts with the occurrence of Collina, Crassiceras and Furloceras of the Gradata Zone; – the succession of Osperleioceras, with the connection between the “caussenardes”(O. reynesi, O. authelini) forms and those from Algeria (O. nadorense, O. matteii), which is placed at the beginning of the Aalensis Zone; – the succession of Hammatoceratinae: H. roubanense (Gradata Z.), H. bonarellii (Bonarellii Z.), H. speciosum (Speciosum Sub-zone), followed by Crestaites meneghinii (Reynesi Sub-zone and Meneghinii Z.); Pseudaptetoceras appear next (Aalensis Zone). The dynamic evolution of the sector is characterized by the persistence of marly sedimentation during the Meneghinii Zone, in probable relation to the paleostructural play of the Arunca-Montemor meridian axis.