Ensaio de síntese crítica acerca do Cretácico terminal e do Paleogénico de Portugal

A synthetic essay about portuguese Late Cretaceous (Upper Campanian-Maastrichtian) and Paleogene is presented. This does include most of the so far known data, a critical approach to the problems of such formations, and to previous works on them. Our viewpoints (party original) are exposed in a shorter text in French where most of the discussion was suppressed (see reference in Resumo).

Notas sobre depósitos de Taveiro estratigrafia, paleontologia, idade, paleoecologia

This paper reports some research work that has been done to support Geological Survey's field work for the 1:50.000 Carta Geológica de Portugal, (sheets 19-C Figueira da Foz and 19-D Coimbra-Lousã). Its main purpose was to establish the age of some continental formations. At Cerâmica do Mondego, Lda. near Taveiro, two series were observed. The lower one is mainly pelitic, montmorillonite being predominant. It also includes some sandy beds and channel deposits with high energy sediments (conglomerate with limestone pebbles). The upper series lies unconformably upon the former, and there is a neat discontinuity surface between the two. It mainly consists of sands, kaolinite being the most abundant of the clay minerals. This seems to indicate an intensive weathering, an acid, well drained environment and transportation by quite high energy running waters. No fossils were recorded. Preliminary paleontological results are presented, along with some data concerning other localities (Aveiro, etc). Fossils found in the lower series are: gastropoda (Bulimus gaudryi, TV. 15 bed), several vertebrates (TV. 18), fishes (TV. 19?) and plants (TV. 19-TV. 24). Vertebrata belong to the same fauna as that from Vizo, Aveiro, etc. The presence of mammals is most important as only a single tooth was previously know in Europe (Southern France) in Late Cretaceous formations. Elsewhere there are some mammalian remains in Peru besides the rich assemblages found in the USA and Mongolia. Plants are representative of the «Debeya flora» well known at several localities in Beira Litoral province, in «Buçaco sandstones», and in Lisbon's «Basaltic Complex». The most important stratigraphical conclusion is that the lower series is Upper Campanian and/or Maastrichtian in age, and not Tertiary as sometimes it has been considered. As at Aveiro, «Bebeya flora» occurs in-beds somewhat higher than those with the Aveiro-Vizo-Taveiro vertebrate fauna. Correlation with other «Debeya flora» localities are now more clear. Data concerning Taveiro lower series, in the whole, point out to a rather warm (and moist?) environment in an occasionally (seasonally?) flooded region.

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).

Sobre a ocorrência de copiapite na orla meso-cenozóica ocidental de Portugal

The occurrence of a copiapite in the Paleogenic (?) formations of Vale Furado (South of S. Pedro de Muel, Portugal) is described, X-ray, DTA and TGA data and a chemical analysis of this mineral are presented.

Nouvelles espèces d’ostracodes de l’Albien et du Cénomanien d’Estremadura (Portugal)

Examination of samples from eight outcrops from Albian and Cenomanian of Estremadura, induced to take a census of sixty-two species and subspecies of Ostracodes among which fifteen are new and described here. Their associations pennited - first, to characterize three faunistic sets: a lower and middle Albian set with a mediolittoral and infralittoral (shallow marine} sedimentation; an upper Albian s.l. (near formations of Rudists}; a lagoonal lower Cenomanian; - on the other hand, to state local comparisons with the middle Cretaceous of Southern France, of the South-pyrenean Zone (Sierra d' Aulet: district of Sopeira), of the district of Oviedo (Northwestern Spain), and of the Aragonese Iberian Range (Aragon and Maestrazgo), placing in a prominent position faunistic exchanges of Ostracodes between the above-mentioned regions and the Estremadura, during the lower Cenomanian.

Vertébrés du Miocène moyen de Amor (Leiria) - importance stratigraphique

Some outcrops in the western part of Leiria's diapir yielded continental fossils in five points near Amor village (mammals, other vertebrata, and gastropoda). This is most significant as it is the first locality where miocene age could undoubtedly been ascribed to formations northwards the Iberian Central Chain and Nazare's accident. Mammalian fauna comprises 18 taxa. A new cricetid species, Fahlbuschia freudenthali n. sp. is described. This fauna allows to date fossil-bearing units from Upper Orleanian, MN5 mammal zone, that may be correlated to Upper Langhian marine stage. As the fauna is quite varied, it is possible to recognize the main characters of environment and of climatic conditions. It may probably be assumed that at the time the climate was of mediterranean type, generally warmer than today.

Les ostracodes du Miocène inférieur de la region de Lisbonne (basin du Tage)

Forty-five species of ostracoda from the Aquitanian of the Lisbon area, belonging in thirty-two genera, are presented. These are the first species belonging to this group reported for the Miocene formations in Portugal. Ostracoda assemblages are typical of fresh water, brackish and marine environments (littoral and inner continental shelf). References are made to the stratigraphically more significant species. Data on the paleoenvironments are also presented. A list of the studied species includes a comparison with their distribution in the Aquitaine and Rhone Miocene basins.

Estratigrafia do Caloviano do Algarve oriental

The comparative study of the Callovian sections in eastern Algarve allowed us to demonstrate that the discontinuity surface at the base of Malm lies always over the Lower-Callovian, as opposite to what happens in western Algarve; the Bathonian-Callovian transition, continuous in western Algarve (Mareta beach) is marked, in eastern Algarve, by a generalised discontinuity of variable vertical extention. It is verified that, in eastern Algarve, the Callovian formations are always or at the nucleus of anticlinal structures, probably linked to halokinetic tectonic activity, or in large radins folds derived from compressive phases.

Evolução paleogeográfica e paleobiogeográfica do Caloviano-Kimeridgiano do Algarve

The littoral and the «barrocal» of the Algarve correspond in part to a meso-cenozoic sedimentary basin with a deeping south monocline structure, cut by North-South faults and by two East-West longitudinal flexures. The lithostratigraphic and chronostratigraphic study of the Jurassic formations, undertaken during the last years, allow a better knowledge of the paleogeographic and paleobiogeographic evolution of these formations and particularly of the Callovian-Kimmeridgian. Lower Callovian facies, being similar from Sagres in the West to beyond Tavira, show the uniformity of the sedimentary conditions. Since Middle Callovian, the beginning of the regressive cycle is responsible for a major unconformity between Dogger and Malm. During the Lower Oxfordian a new sedimentary cycle begins with a transgression afecting the region south of the Albufeira-São Brás de Alportel-Tavira line thus originating a gulf centered in the Loulé area which rapidly diminishes since the Lower Kimmeridgian. The faunistic affinities are always tipically tethyan although some classic boreal fauna exist, in contrast with the Northern Tagus basin (where affinities are sub-boreal during the Callovian).

Matching CO2 large point sources and potential geological storage sites in mainland Portugal

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia do Ambiente, Perfil Gestão e Sistemas Ambientais

Evolução geológica de Portugal continental durante o Cenozóico - sedimentação aluvial e marinha numa margem continental passiva (Ibéria ocidental)

6º Simposio sobre el Margen Ibérico Atlántico MIA09

Utilização de um sistema de informação geográfica na caracterização de áreas de dragagem

Dissertação apresentada como requisito parcial para obtenção do grau de Mestre em Ciência e Sistemas de Informação Geográfica

Nouvelles données sur le Miocène moyen marin ("Sallomacien") de Gironde (Bassin d'Aquitaine-France) Approche des paléoenvironnements New data about the maine Middle Miocene ("Sallomacian") of Gironde (Aquitaine Basin); paleoecological outline

The Mid Miocene marine formations of Salles area (former "Sallomacian" stage) have been studied again from numerous outcrops and cores. The deep structural framework influences notably of the characteristics and distribution of the deposits, which are neritic. The stratigraphy is stated precisely thanks to the planktonic fauna and floradetailed examination (probably Serravallian zones NN6 - N12). Several paleobiofacies are reconstituted from the rich invertebrate faunas, which give also paleoclimatic data.

The marine Neogene of Eastern Venezuela : a preliminary report

Proceedings of tile 1" R.C.A.N.S. Congress, Lisboa, October 1992

The detrital origin of the Moncorvo ordovician ironstones

The Moncorvo Ordovician ironstones in northeastern Portugal consist of iron ore sedimentary horizons frequently interbanded with psamites and quartzites. Ore reserves may probably exceed 1 000 million tonnes and this makes Moncorvo the largest iron ore deposit in the European Union. Compact poorly banded massive layers may exceed 90 meters in thickness which is quite an extraordinary feature for a Phanerozoic deposit. If the thickness of Precambrian deposits may reach a few hundred meters, the thickness of Phanerozoic deposits never exceed a maximum of 15 meters generally forming a number of comparatively thin layers confined to a particular member of a sedimentary sequence. A detailed microscopic analysis of the ores revealed that initially a compact magnetite/quartzite layer, detrital in character (the magnetite occasionally showing chromite cores), was deposited by entrapment in near shore lagoons where rivers debouched, rather than in the open sea. This stage was followed by oscilating and transgressive shore lines which gave rise to breaks in sedimentation in combined river delta and shallow water marine environment where detrital material and fine iron oxide and clay suspensions were deposited in fluctuating environments. These events gave rise to layers of both magnetite (martite) and specularite intergrown with quartz, silicates and phosphates. Textural and mineralogical studies show that the deposits consist of ferruginous clastic sediments and are not chemically deposited cherts. Field, geological and palaeontological evidence also supports a detrital origin, the facies being typical of zones rich in oxygen and close to the feeding continent. The uncommon huge development of Moncorvo was due to the fact that the deposits occur in restricted basins on a continental platform were clastic sediments were predominantly deposited. Not only morphologically but also chemically the deposits are more similar to Precambrian iron formations than to Phanerozoic ironstones.