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Die oberjurassische Korallenfazies von Algarve (Südportugal)

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... In the north it is limited by the carboniferous rocks of the South Portuguese Zone, which is a part of the Iberian Massive and corresponds to the Paleozoic basement of the younger formations (Terrinha et al., 2013), and which constitutes the mountains of Caldeirão, Espinhaço do Cão, for instance. 262 Source: Rosendahl (1985) The carboniferous sandstones and shales of "flysch"-type, deposited during the Carboniferous period, about 360 to 310 million years ago (International Commission on Stratigraphy, 2018), have suffered metamorphism and folding during the variscan orogeny, which took place from about 390 million to 250 million years ago and had affected a big part of western and central Europe (J. T. Oliveira et al., 2013). ...
... On the top of the cliff, limestones and marls of Lower Kimmeridgian age, about 156 million years ago (International Commission on Stratigraphy, 2018), contain a rich fauna of well-preserved fossil corals and other fossils (figure 5). More than 40 different species of Upper Jurassic corals were identified in this place (Rosendahl, 1985), so it was characterized by a specialist of Mesozoic fossil corals as belonging to the "top ten worldwide" (Hannes Löser, oral communication, 2011). Because of its paleontological richness and the spectacular landscape of the cliffs, the location was classified as a geosite (LNEG, 2010). ...
... In the hills at the south-west of Santa Catarina da Fonte do Bispo (central Algarve), a coral bed with long branched corals can be seen in a sequence of Lower Kimmeridgian limestones (figure 7), with an age of about 156 million years (International Commission on Stratigraphy, 2018). One species dominates the fauna, which means that the paleoenvironment was not optimal for the corals (Rosendahl, 1985). An almost straight line cuts the coral bed upper part. ...
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The Algarvian coast (Southern Portugal) is known for its beaches. However, many tourists don't want to spend their whole holidays only at the beach, so cultural tourism can fill a gap together with natural tourism. Important branches of natural tourism of Algarve are bird-watching and guided tours, which may include visits to geologically interesting sites (Geotourism). These activities are aimed to people with sporting and scientific interests. Algarve has a big potential for Geotourism due to the large number of geologically interesting places and areas. Geotouristic activities joined with the observation or visit of cultural, mainly vernacular subjects (for instance: terraces and cultural landscapes, agricultural and ethnological traditions, villages) result in a more complete touristic offer than each part isolated and can be done all over the year. The creation of a Geopark by UNESCO, for instance, includes both natural and cultural heritage. Like the cultural heritage, the geological heritage should be valorized by tracking paths for hiking with information tables, guided visits, folders and so on, to be disseminated by the tourist information offices, apps, new technologies, hotels and other touristic installations. When touristic activities lead to a better knowledge of the natural and cultural sites, their conservation may be easier, because the local residents are getting conscious about their value. Regular visits of the sites are used to control their condition. Thus, Geotourism and cultural tourism contribute to the preservation of the geological heritage and the landscape, which is also an environmental and cultural heritage.
... sp. represents the first citation of the genus in the Bajocian, and is filling the gap for this Lazarus genus between the Lower Jurassic occurrences of Tadjikistan (Melnikova and Roniewicz, 2021) and the Oxfordian occurrences in Europe (Roniewicz, 1976;Rosendahl, 1985;Turnšek, 1997). We note that the stratigraphic range of Atelophyllia (even when based on very few samples) remains limited to the Bajocian. ...
... The Vršatec coral reefs were inhabiting the optimal window typical of Bajocian reefs, widely affected by macroborings (mainly sponges and bivalves) and coated by microbial crusts. The classical set of Bajocian species is described, however, with the new species Proaplophyllia slovakensis that represents a significant occurrence in Bajocian for this Lazarus genus between Liassic occurrence of Tadjikistan (Melnikova and Roniewicz, 2021) and Oxfordian ones in Europe (Roniewicz, 1976;Rosendahl, 1985;Turnšek, 1997). It is also the first appearance date of the genus Enallhelia that was formerly known from the Bathonian: Tomes (1883) for E. clavata and/or Tomes (1885) for E. socialis and /or Michelin (1846) for Euhelia gemmata. ...
... . Geological sketch of Algarve (adapted from Rosendahl, 1985). ...
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The region of Algarve (Southern Portugal) is a touristically very well developed area. Its geological heritage, represented by geosites and other interesting places, is very rich. In spite of this wealth, and even though there may be a lot of interested visitors, there are very few geotouristic activities in Algarve. Some measures for the development of geotourism in this re-gion will be discussed.
... Would it be possible that these "bushes" were grazed by dinosaurs, which caused this line? In reality, the fossil "bushes" are colonies of fossil corals which formed branches with a length of up to 0,5 meters, and which grew in a marine environment with shallow water (Rosendahl, 1985). The growth of these branches is very dense, probably to protect themselves against a presumed strong water movement of the sea. ...
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Many tourists don't want to spend their holidays only at the beach and others arrive to their destination for cultural or natural reasons. Some are attracted by creative activities. An upcoming touristic branch which joins cultural and natural tourism is Geotourism. A "georiddle" may increase the visitor's interest in geological and cultural themes and challenge his creativity. The following methodology is adopted to reach these objectives: The guide gives basic information in a geologically interesting site and asks the participants about details of what can be seen. By brainstorming and discussion, they may solve the problem or not; in any case the participants are encouraged to foster their creativity by interactive processes. Then, the guide explains his opinion about the solution of the "georiddle", and the discussion can begin again. Enigmatic structures may be found in construction stones of built heritage, as well as in geological outcrops in the countryside. A "georiddle" can be posed in other fields, like vernacular cultural heritage. For instance, drystone constructions are interfaces between geological and cultural heritage. Here, the riddle's aim may be to discuss about the reason of their spatial arrangement and purpose. As a result, it is expected to awaken the visitor's curiosity and creativity and to increase and broaden his field of knowledge.
... On the other hand, the use of groundwater for irrigation combined with evaporation on the field, led to salinization of soils. The sealing of the ground caused by edifications and streets avoided the recharge of the [20]) aquifer with fresh water in large areas, increasing the concentration of salt in the groundwater in the littoral area. ...
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This paper aims to enhance the functions of terraces and drystone walls as structural elements and distinctive factors of the traditional rural zone known as the barrocal of the Algarve, south of Portugal. In fact, such elements define the character of the landscape that forms the background of a traditional touristic region along the coast. The core of this paper will be the knowledge of construction processes, spatial distribution, and hydrological, ecological, economic and social functions, once it is quite necessary for the Algarve region. Some projects and studies have been developed in the Mediterranean context, but there is not enough research on this subject in the south of Portugal. Secondly, the social meaning, or acknowledgement of the landscape characterized by drystone wall structures, will be the key for finding real possibilities of renewing the terraces. Therefore, the landscape will be assumed as a common good. In this subject, we take into account the potential role and sensibility of tourists and resident population. Beyond static patrimonial statutes, we can design some practical possibilities to enhance plastic features and new uses leading to an acknowledgement of the Algarvian drystone wall structure, referred as a part of Mediterranean coastal landscapes. Some examples that can add cultural and touristic value could be: recreation areas for urbanites, new cooperative forms of agriculture, hobby farming, workshops about harvesting traditional products, circuits and pedestrian paths, and interchange with similar Mediterranean regions defining broader circuits.
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A review on the findings of chaetetid sponges in Mexico is made. Up to date, two localities house the whole diversity of Mesozoic chaetetids in the country consisting of three species, all of them from the Cretaceous. The studied localities are Arroyo La Cruz, in the state of Oaxaca, and El Gorrión, in the state of San Luis Potosí. At Arroyo La Cruz, outcrops from the San Isidro Formation (of a Hauterivian-Barremian age) can be found, whereas Coniacian to Santonian deposits from the Tamasopo Formation can be located at El Gorrión. Acanthochaetetes huauclillensis Sánchez-Beristain and García Barrera is the only species that can be found in the state of Oaxaca. In contrast, two species of the genus Blastochaetetes, namely Blastochaetetes flabellum Michelin and Blastochaetetes reitneri nov. sp. Sánchez-Beristain and García-Barrera, make up the diversity of the El Gorrión locality. Blastochaetetes reitneri nov sp. Sánchez-Beristain and García-Barrera can be differentiated from other species in the genus by the presence of intertabular spaces measuring no less than 2 mm, and thick tabulae (as much as 0.13 mm). These are unique features among the genus. For its part, Blastochaetetes flabellum Michelin is easily recognisable by the pattern formed by parallel concentric bands on the surface of the specimens. On the other hand, Acanthochaetetes huauclillensis Sánchez-Beristain and García-Barrera can be distinguished from other members of the genus Acanthochaetetes by the scalariform pattern formed by the tabulae at adjacent calicles. Palaeoecologically, Mexican chaetetid sponges more or less show the same growth forms, from domical to laminar, both of which could be related to constant sedimentation rates in a low-energy environment (reef-or reef-like settings). However, microbialites are often associated to Acanthochaetetes huauclillensis, whereas no hint to these deposits can be found related to Blastochaetetes. Mexican chaetetids also have important palaeobiogeographic and stratigraphic implications. Evidences of Blastochaetetes for the country represent the most recent record for the genus. This could mean that it dispersed westward from Europe, where the oldest records can be found. On the other hand, the finding of Acanthochaetetes in Mexico during the Hauterivian to Barremian implies its dispersion to the Western Tethyan Realm prior to its diversity peak in Europe in the Albian. The fact that Mesozoic deposits are widespread in Mexico implies the possibility of finding multiple specimens in the future, which would deepen the knowledge on these organisms. Moreover, since one of the genera studied here -Acanchochaetetes-is an extant taxon, the possibility of finding well-preserved post-Cretaceous chaetetid specimens for further studies is high. RESUMEN: Se lleva a cabo una revisión de los hallazgos de las esponjas quetétidas en México. A la fecha, dos localidades albergan toda la diversidad de quetétidos mesozoicos del país conformada por tres especies, todas ellas del Cretácico. Las localidades estudiadas son Arroyo La Cruz, en el estado de Oaxaca, y El Gorrión, en el estado de San Luis Potosí. En Arroyo La Cruz se pueden encontrar afloramientos de la Formación San Isidro (de edad Hauteriviano - Barremiano), mientras que depósitos del Coniaciano a Santoniano de la Formación Tamasopo pueden ubicarse en El Gorrión. Acanthochaetetes huauclillensis Sánchez-Beristain y García Barrera es la única especie que se puede encontrar en el estado de Oaxaca. Por el contrario, dos especies del género Blastochaetetes, a saber, Blastochaetetes flabellum Michelin y Blastochaetetes reitneri nov. sp. Sánchez-Beristain y García-Barrera, conforman la diversidad de la localidad de El Gorrión. Blastochaetetes reitneri nov sp. Sánchez-Beristain y García-Barrera se puede diferenciar de otras especies del género por la presencia de espacios intertabulares que miden no menos de 2 mm y por el grosor de sus tábulas (llegando incluso a medir 0.13 mm). Estas son características únicas dentro del género. Por su parte, Blastochaetetes flabellum Michelin es fácilmente reconocible por el patrón formado por bandas concéntricas paralelas en la superficie de los ejemplares. Por otro lado, Acanthochaetetes huauclillensis Sánchez-Beristain y García-Barrera se puede distinguir de otros miembros del género Acanthochaetetes por el patrón escalariforme formado por las tabulas en las calículas adyacentes. Paleoecológicamente, los quetétidos mexicanos muestran más o menos las mismas formas de crecimiento -de dómica a laminar-, las cuales podrían estar relacionadas con tasas de sedimentación constante en un ambiente de baja energía (arrecife o ambientes similares a arrecifes). Sin embargo, es posible encontrar microbialitas a menudo asociadas con Acanthochaetetes huauclillensis, mientras que no se pueden encontrar indicios de este tipo de depósitos relacionados con Blastochaetetes. Los quetétidos mexicanos también tienen importantes implicaciones paleobiogeográficas y estratigráficas. Las evidencias de Blastochaetetes para el país representan el registro más reciente para el género. Esto podría significar que se dispersó hacia el oeste desde Europa, donde se pueden encontrar los registros más antiguos. Por otro lado, el hallazgo de Acantochaetetes en México en el intervalo Hauteriviano - Barremiano implica su dispersión al Reino del Tethys Occidental antes de su pico de diversidad en Europa durante el Albiano. El hecho de que los depósitos mesozoicos estén muy extendidos en México implica la posibilidad de encontrar múltiples ejemplares en el futuro, lo que profundizaría el conocimiento sobre estos organismos. Además, dado que uno de los géneros estudiados aquí -Acanchochaetetes-es un taxón existente, la posibilidad de encontrar especímenes de quetétidos post-Cretácicos bien conservados para estudios adicionales, es alta. PALABRAS CLAVE: Quetétidos, Esponjas fósiles, Cretácico, México, Blastochaetetes, Acanthochaetetes.
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Since becoming settled, Man had the need to shape the territory in his benefit, gaining ground for agricultural activity. Drystone walls were the way found to overcome sharp slopes. The way these walls are arranged in the territory is not random, as it may seem at first glance: they are disposed in the best way to facilitate the agricultural activity, taking into account the natural factors of the territory where they are located, such as orography, climate or geology. Taking as study cases two regions in Portugal under slightly different climate regimes, one located in the Algarvian Barrocal and the other located in the Center, we intend to compare and advance with explanations as to the way drystone walls are disposed and their relation to the territory. To achieve the objectives bibliographical and photographic studies, as well as interviews with the inhabitants of these areas, and cartographic and field surveys were carried out. Whereas the purpose, materials and construction characteristics were achieved by the previous, their disposition and relationship with the orography were carried out by the latest. Particularly, field surveys were made by digital stereo-photogrammetry applied to several overlapping nadiral photographic images from different perspectives acquired by an unmanned aerial vehicle along its flying pathways that allowed for very high-resolution geographic data. Where such surveys were not made, cartographic data were used instead. Through the dissemination of such vernacular heritage, it becomes valued and known. In this way, people will attribute cultural and patrimonial value, protecting it, especially the local population that tends not to attribute any value to this "minor" heritage, contributing to its disappearance. There are still not much works about this subject in the areas analyzed here, so this paper has an added value, in order to disseminate and create added value to these kind of heritage.
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In the Late Jurassic and Cretaceous the warm shallow water seas were marked, within benthic marine organisms, by rudist bivalves, a peculiar group of mollusks that originated in the Late Jurassic and became extinct at the end of the Cretaceous. In this paper their global distribution in neritic carbonates is considered since their first appearance in the middle Oxfordian up to the first main extinction event at the end of the early Aptian. The information and data regarding global rudist occurrences throughout neo-Tethys and paleo-Pacific oceans are critically reprised from literature and organized in an Oxfordian-early Aptian Rudist database (OXAP_RDB) that encompasses 235 rudist-bearing localities all across the world, with 845 total rudist occurrences, 34 valid genera and 148 species. Actual rudist geographic distribution is investigated in order to contribute to the identification of the paleobiogeographic pattern of these benthic organisms in the paleoclimatic and paleogeographic setting of neo-Tethys and paleo-Pacific oceans, allowing to reconstruct dispersal patterns and to define four broad paleobiogeographic Provinces in the Barremian–early Aptian.
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Une nécessaire révision des coraux plocoïdes jurassiques en morphologie, morphométrie, systématique et en nomenclature a été réalisée grâce à des spécimens-types, du matériel de collection, ou issu de la littérature. Des structures dont une nouvelle muraille, l'étallonothèque et des types d'auricules ont été identifiés. Un stade initial ontogénique tétraméral a été observé pour la première fois chez Heliocoenia et Pseudocoenia. Ceci est en désaccord avec la définition traditionnelle sur le développement fondamentalement hexaméral chez les Scleractinia. L'étude systématique aboutit à une réorganisation des familles, des genres et de leurs synonymies. Des espèces sont décrites avec des limites encore parfois ambigües nécessitant une approche morphométrique plus approfondie pour être reproductible. Les positions systématiques prises sont traduites dans le sens de la préservation de la stabilité de l'usage des noms, des actes nomenclaturaux sont proposés dans ce sens. Deux méthodes morphométriques ont été appliquées aux contours 2D des sections de polypiérites. L'analyse de Fourrier Elliptique a été utilisée sur des coupes transversales théoriques et réelles. Les résultats montrent les différentes symétries et certains genres distingués par cette méthode. L'analyse des dimensions fractales de modèles théoriques, des coupes étudiées, ou issues de la littérature ont été analysées. Les formes étudiées se placent selon un gradient de complexité croissante du contour correspondant à la maximisation de l'interface squelette-porosité. Le long de ce gradient, les différents taxons se répartissent, leur distinction restant souvent délicate par suite d'un léger recouvrement
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The Hainholz quarry in the Osterwald hills of NW-Germany is the most impressive outcrop in the Lower Saxony Basin exposing Late Jurassic (Korallenoolith, Oxfordian) coral buildups. The Korallenoolith deposits in the quarry commence with a oolitic sequence about 20 m thick which is limited by a distinctive hardground at its top. This sequence is overlain by the so called “Obere Korallenbank”-Member about 13 m in thickness which is mainly build up by coral reef complexes. Throughout a lateral extend of about 400 m exposed in the quarry, the Obere Korallenbank Member shows numerous pillar-shaped reefal build ups which are flanked by a reefal debris limestone. The coral fauna of the in situ reefal bioconstructions comprises not less than 37 taxa most of which have been described from the Lower Saxony Basin for the first time. Probably, the pillar-shaped reefs formed a small positive relief of only a few dm against the debris deposits during deposition. The interreef debris limestones in the lower and middle part of the Obere Korallenbank Member show three intercalated biostromal coral layers. In the upper part of the member, the interreef facies is represented by a mikritic peloidal limestone rich in sponge remains and, unusual in such a depositional environment, ammonites (Dichotomosphinctes bifurcatoides, D. sp.). Additionaly, at the top of of the peloidal limestone a layer enriched in nerineids and other gastropods limits the reefal constructions of the Obere Korallenbank Member against the overlying “humeralis-Oolith” sequence. On the basis of the facies development of this depositional sequence the reef formation in relation to sealevel changes is discussed.
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