Ana Cristina Azerêdo

Ana Cristina Azerêdo
University of Lisbon | UL · Department of Geology, Faculty of Sciences

PhD

About

132
Publications
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Introduction
Ana Cristina Azerêdo currently works at the Department of Geology, Faculty of Sciences, University of Lisbon. Ana does research in Carbonate Sedimentology, including Petroleum Reservoirs, Stratigraphy and Palaeoecology . Their most recent publication is Carbonate reservoir outcrop analogues with a glance at pore-scale (Middle Jurassic, Lusitanian Basin, Portugal).

Publications

Publications (132)
Article
Full-text available
Upper Toarcian ostracod assemblages from Boca da Mata, Alvaiázere, Central Portugal, are described to complement earlier work on the ostracods of the Toarcian GSSP at Peniche, western Portugal. A total of 44 species are recorded and the following new taxa described: Cytheropterina ainsworthi sp. nov., Eucytherura alvaiazerensis sp. nov., Otocythe...
Article
New stable carbon isotope and biomarker data for oils and source rock extracts from the Lusitanian Basin, Portugal, were studied in order to investigate the petroleum systems which are present there. The new analytical data was combined with data presented in previous publications, and oil‐oil and oil‐ source rock correlations were carried out. Thr...
Article
Full-text available
An integrated stratigraphic analysis of the Coimbra Formation was performed in the S. Pedro de Moel outcrops of the Lusitanian Basin (Portugal). This unit is dated from the lower–upper (Oxynotum Chronozone) Sinemurian and is subdivided into eight informal subunits. Except for its base, consisting of dolostones and microbialites, much of the success...
Article
Outcrop observations offer valuable insights into depositional architecture as a primary control on facies and reservoir properties variability, in contrast to subsurface cases, where observation points are limited to well locations. Two dominantly high-energy shallow-water carbonate case studies were analysed, including outcrops of a Bathonian-Cal...
Article
The Toarcian–Aalenian(?) Cabo Carvoeiro Formation in the Lusitanian Basin (LB), Portugal, is characterized by a succession of mixed carbonate–siliciclastic sediments deposited under the influence of an active horst-graben system caused by the progressive tectonic uplift of the Berlengas basement block. Towards the top of the succession, this format...
Article
The Santos Basin in offshore Brazil belongs to the major carbonate reservoir province known informally as the Pre-Salt. A detailed analysis of cores, plugs, sidewall samples and thin-sections from two wells in a sector of this basin was undertaken, on an interval corresponding to the upper part of the Lower Cretaceous Barra Velha Formation. Several...
Article
Full-text available
The stratigraphical occurrence of ostracod assemblages of the uppermost Pliensbachian (emaciatum Biozone) and Lower–Middle Toarcian (polymorphum, levisoni and bifrons biozones) at Peniche, western Portugal, is reported, an interval that encompasses the Toarcian Global Boundary Stratotype Section and Point (GSSP) and the Toarcian Oceanic Anoxic Even...
Article
The Lower Jurassic Água de Madeiros (AM Fm) and Vale das Fontes (VF Fm) Formations, and the Upper Jurassic Cabaços Formation (Cab Fm) are considered the most important units with petroleum source-rock potential in the Lusitanian Basin, and the likely sources for its widespread hydrocarbon occurrences. Nonetheless, the bottom-water redox conditions...
Article
The present work reports the first study on fault-controlled breccias cemented by low-Ti iron-oxides cropping out in Valverde (Maciço Calcário Estremenho, Lusitanian Basin, Portugal). The mineralized bodies: (i) occur in jogs of a WNW-ESE fault zone that comprises four segments, forming an irregular en échelon array of arched geometry; and (ii) are...
Article
The Middle Jurassic carbonate successions from the Lusitanian Basin (Portugal) show a range of facies deposited across a ramp depositional system, well exposed over large areas. These facies are valuable for understanding reservoirs and related seal and trap configurations, namely in carbonate ramps. This paper documents primarily shallow-water uni...
Chapter
During the Late Triassic-Middle Jurassic interval Iberia acted as a passive margin, where extensional or transtensional faulting, linked to the propagation of the Central Atlantic and the opening of the Ligurian Tethys, generated a NW and NE trending fault system that conditioned facies and thickness distribution. These faults also favored the impl...
Article
Full-text available
This work presents unpublished information on the petrography and diagenesis of the Cambambe Basin. The deposition of the Cambambe Basin started at 84 Ma ago. This basin consists of a Cretaceous volcanic-sedimentary sequence cropping out in the municipalities of Chapada dos Guimarães and Nova Brasilândia. The volcanic-sedimentary sequence starts wi...
Article
This work presents unpublished information on the petrography and diagenesis of the Cambambe Basin. The deposition of the Cambambe Basin started at 84 Ma ago. This basin consists of a Cretaceous volcanic-sedimentary sequence cropping out in the municipalities of Chapada dos Guimarães and Nova Brasilândia. The volcanic-sedimentary sequence starts wi...
Poster
Full-text available
A Bacia de Campos está situada na região sudeste do Brasil e é limitada por dois altos A estratigrafia de sequência de alta resolução, baseada na análise conjunta de métodos sísmicos, testemunhos, amostras laterais e lâminas, vem sendo utilizada como uma importante ferramenta para melhor compreender a arquitetura deposicional, geometria e fácies do...
Article
Shallow-water Cretaceous, carbonate platform archives have only rarely been explored through their elemental signature. Yet, facies-sensitive geochemical records can shed light onto the specific dynamics of shallow/proximal settings, where changes in depositional conditions are pronounced. Changes stemming from early and later diagenetic processes...
Article
This study tests the hypothesis that the early diagenesis of aragonite shells should differ fundamentally between marine and freshwater environments. This is predicted to be the case because aragonite is highly susceptible to dissolution in the TAZ (Taphonomically Active Zone) in low energy marine settings due to acidity caused largely by the oxida...
Conference Paper
Full-text available
The Polvoeira Mb of Água de Madeiros Fm (Upper Sinemurian to lowermost Pliensbachian) is one of the units in Lusitanian Basin with potential for hydrocarbon generation; it comprises alternations of marl/limestone with several black-shale levels [1]. Twelve samples representing different black shales were selected for whole-rock geochemistry. Two su...
Conference Paper
Full-text available
Pb isotope compositions for three sample sets of pyrite in NNW-trending fracture arrays that crisscross Lower Jurassic hemipelagic series at S. Pedro de Moel region [1] indicate similar fluid sources and multiple migration events. Indeed, the 207Pb/204Pb and 208Pb/204Pb ratios, as well as µ-values, are relatively homogeneous, ranging from 15.641 t...
Article
Seeking to identify the oils groups accumulated in the Jurassic of the Lusitanian Basin and the source rock of each group, stable carbon isotope and gas chromatography coupled with mass spectrometry analyses were performed in oils and oil shows from the main discoveries, and on representative organic extracts from the potential source rocks, select...
Article
A study of new material of Cylindroporella ? lusitanica Ramalho, 1970, from the Upper Jurassic (Oxfordian) strata of Portugal identified features not observed previously. This includes the pattern of its laterals, including the gametophores. The algal body plan is unique and justifies the taxonomic reassessment of this species and the introduction...
Conference Paper
Characterizing highly heterogeneous carbonate reservoirs requires the integration and detailed analysis of petrophysics, facies, diagenesis, geometry, depositional environments and lateral and vertical variability. This is often challenging to conceptual models at oil-field scale, as this thorough analysis is hard to fully reproduce at reservoir-sc...
Article
Full-text available
Late Callovian (athleta Chronozone) age sediments of Pedrógão, west coast Portugal, yielded a low diversity ostracod assemblage with relatively little in common with coeval NW European assemblages except at the weak level of comparative (cf.) species identification. Five new marine species are described (Neurocythere multiforma sp. nov., Palaeocyth...
Poster
Full-text available
Abstract Dolomitization is the most significant syndepositional and diagenetic process within the early Lower Jurassic shallow-marine carbonate succession cropping out in the eastern part of the Lusitanian Basin (Portugal). In this proximal domain, the Coimbra Formation (lower Sinemurian) overlies a Hettangian muddy-evaporitic complex and is compos...
Article
The unusual occurrence of calcretes and prominent organic matter in the Middle Jurassic (Lower Bathonian, Serra de Aire Formation) of the Lusitanian Basin of western Portugal (Western Iberian Margin) revealed a complex palimpsest exposure record, here interpreted as reflecting hydrological changes caused by phases of emergence and immersion. It ser...
Article
Sinemurian ostracodes from the Lusitanian Basin (western Portugal, Iberian Peninsula) were studied using twelve samples from the marl-limestone succession of the Coimbra Formation at S. Pedro de Moel, north of Lisbon. The detailed taxonomical study identified 11 genera and 14 species, among which 3 are new species: Phraterfabanella boomeri Cabral a...
Article
In order to identify the source rock of the oil found in the Benfeito-1 well (Montejunto region) geochemical analyses were carried out on rocks from this well, belonging to the Santo António - Candeeiros (Moleanos Member equivalent, Callovian), Cabaços (lower? - middle Oxfordian) and Montejunto (middle - upper Oxfordian) formations, on rocks of the...
Article
Full-text available
The west-central part of the Lusitanian Basin has excellent conditions for the observation and study of Jurassic stratigraphic successions, with a high Geological Heritage interest whose valorization and preservation is important. In this work, following a generic geological characterization (particularly from a sedimentary standpoint), the heritag...
Conference Paper
Full-text available
A lithological and lithostratigraphical characterization of the Coimbra Formation (Sinemurian) cropping out at S. Pedro de Moel region is presented. This is the sector of the Lusitanian Basin where the vertical expression of this unit is better exposed. The detailed sedimentological analysis of the whole stratigraphic carbonate succession, recorded...
Chapter
Full-text available
The S. João das Lampas section, in the Sintra region (Lusitanian Basin, Portugal), exhibits a highly fossiliferous marl–limestone Cenomanian succession and belongs to the Caneças Formation. In this work, we present data from ongoing studies on ostracods and microfacies to address palaeoecological issues within the regional framework. The fossil ass...
Article
Full-text available
The Middle–Upper Jurassic transition is a geodynamic benchmark in the evolutionary history of several peri-Atlantic basins. Contrary to the vast Tethyan and peri-Tethyan areas, in the Lusitanian Basin (Portugal), this interval corresponds to a major basin-wide disconformity preceded by a complex forced regression that induced sharp facies variation...
Chapter
Full-text available
Here we present the main results of a study of the high-resolution stratigraphy of the Lower Jurassic organic-rich marine series in the Lusitanian Basin, Portugal. In this basin, the Lower Jurassic consists mainly of an alternating marl–limestone succession (upper Sinemurian–Toarcian), with some intervals enriched in organic matter (upper Sinemuria...
Article
Full-text available
The Lower and Middle Jurassic carbonate series from the Lusitanian Basin were deposited across different evolutionary stages, evidencing marked facies and environmental contrasts over a ramp depositional system deepening towards W/NW. In spite of the diversity exhibited at specific sectors or stratigraphical intervals, at a basin scale sedimentary...
Article
Full-text available
This work presents the main results of the Project ”High resolution stratigraphy of the Lower Jurassic organic-rich marine series in the Lusitanian Basin (Portugal)”, supported by the Portuguese Foundation for Science and Technology. This project was focused on a multidisciplinary stratigraphic analysis based on the study of a range of biotic and a...
Article
Full-text available
Resumo: Estudaram-se, no que respeita os ostracodos, doze amostras margosas recolhidas na série calcária da região de S. Pedro de Moel, aflorante nas arribas das contínuas Praia Velha e Praia da Concha (Formação de Coimbra, Sinemuriano inferior a superior). A fauna identificada é escassa e mal conservada na base, tornando-se progressivamente mais a...
Article
At the Galinha Quarry section, Fátima region, the base of the Serra de Aire Formation (Lower Bathonian) exhibits nice examples of pedogenic limestones (massive, laminar, nodular and brecciated calcretes, always with black-clasts) interbedded with, or grading laterally or vertically into, a range of other deposits, including organicrich sediments th...
Article
Full-text available
The extinction of the Metacopina Suborder (ostracods) in the Early Jurassic is a global event, whose age has been strongly discussed. Over most of the western Europe countries, this ostracod group is usually very well represented throughout the Early Jurassic and then dramatically disappears, being replaced by other ostracod groups with more "moder...
Article
In this study, 31 samples from three key sections where it is possible to observe the Middle-Upper Jurassic transition in the northern part of the Lusitanian Basin were analyzed (Total Organic Carbon and Palynofacies): Cabo Mondego (Figueira da Foz), Pedrógão (Praia de Pedrogão, Vieira de Leiria) and Vale de Ventos (Maciço Calcário Estremenho). The...
Article
Full-text available
The aim of this study was to understand the ostracod distribution in the Upper Sinemurian-lowermost Pliensbachian of S. Pedro de Moel region (top of the Coimbra and Água de Madeiros formations) and Peniche (Polvoeira Member of the Água de Madeiros Formation). At S. Pedro de Moel 39 samples were studied; 4099 ostracods were found and distributed int...
Article
The elaboration of predictive sedimentological models is one of the main tools used in petroleum exploration. The objective of this work is to present a brief sedimentological, stratigraphical, palynofaciological and geochemical characterization of one of the main organic-rich interval and potential source-rock of the Lusitanian Basin: the Marl-lim...
Article
Carbonate reservoirs are commonly heterogeneous and their reservoir quality results from complex interactions between depositional facies and diagenetic processes. The Diagenetic Diagram is a powerful tool that helps in the characterization of the diagenetic processes that have affected the reservoir. From this knowledge, it is possible to signific...
Article
Full-text available
Data on lipids, carbohydrates and proteins of the most expressive black shale (s.l.) intervals of the Early-Late Pliensbachian (Early Jurassic, similar to 187 Ma) organic-rich hemipelagic series of the Lusitanian Basin (Portugal) were determined using a method that has been successfully applied over the last two decades in the characterization of b...
Article
A high-resolution carbon and oxygen isotopic bulk carbonate record from organic-rich hemipelagic series of Early-Late Pliensbachian age (similar to 187 Ma) is presented for the Lusitanian Basin (Portugal) and compared to the record of other sedimentary basins. This dataset provides an excellent basis for discussing newly raised questions concerning...
Conference Paper
Full-text available
Ongoing stratigraphical study at the Serra do Bouro region (Caldas da Rainha) allows mentioning, for the first time in this area, occurrence of the Cabaços Formation (Oxfordian) at outcrop. In spite of the small dimension of the section and the local tectonism, field characterization and sampling of several levels (some discontinuous) was possible:...
Article
The re-evaluation of the charophyte content of 'Purbeckian' sediments from several sections around Lisbon (Olelas and Bronco) and Sintra-Cascais (Murches, Atrozela and Malveira-Guincho) revealed new palaeofloral associations front the Late Tithonian of the South Lusitanian Basin (Portugal). These sections contain Globator rectispirale, G. aff. nurr...
Article
Well-preserved dome-shaped carbonate stromatolites occur in the lowermost part of the Sinemurian of the Lusitanian Basin (Portugal), at S. Pedro de Moel region (W of the basin). Deposition in the region took place on a westward-dipping carbonate ramp. The stromatolitic mounds are not found anywhere else in the Sinemurian of the basin and therefore...
Article
Full-text available
The re-evaluation of the charophyte content of 'Purbeckian' sediments from several sections around Lisbon (Olelas and Brouco) and Sintra-Cascais (Murches, Atrozela and Malveira-Guincho) revealed new palaeofloral associations from the Late Tithonian of the South Lusitanian Basin (Portugal). These sections contain Globator rectispirale, G. aff. nurre...
Article
Full-text available
A recent stratigraphical study in the Serra do Bouro region (Caldas da Rainha, central Lusitanian Basin, Portugal) has allowed recognition of the Cabaços Formation (Oxfordian) at outcrop, for the first time in this area. Previously, within the spatial range of the 1:50.000 geological sheet of the Caldas da Rainha region, the Cabaços Formation was k...