M. L. Canales

Paleoecological quantitative analysis based on benthic foraminifera of the Aalenian–Bajocian boundary (upper Bradfordensis–lower Discites) in the Barranco de Agua Larga section (Betic Cordillera, Southern Spain)

PurposeTo report, for the first time, the benthic foraminiferal assemblages recorded across the upper Bradfordensis–lower Discites ammonite zones (Aalenian–Bajocian boundary, Middle Jurassic) in the Barranco de Agua Larga section (Betic Cordillera, Southern Spain),in order to infer the paleecological conditions that affected their development.MethodsA total of 17 samples were collected in this reference section, and the composition of the foraminiferal assemblages recorded throughout the studied stratigraphical was analyzed using quantitative data obtained through the estimation of relative abundances and the calculation of several diversity indexes.ResultsThe assemblages are abundant (a total of 3, 139 well-preserved specimens) and diverse(82 species). Their composition displays close similarities to those already described for the Jurassic carbonate platforms of the Boreal Realm (Type-A), Boreal Atlantic subdivision.ConclusionsThe studied assemblages were developed in distal marine environmental conditions, at a depth situated above the level of the calcite compensation, well oxygenated and with normal salinity, although for certain times (Aalenian–Bajocian boundary) unfavorable environmental conditions could have developed. The sharp decrease in the abundance and diversity that was recorded during the Aalenian–Bajocian transition has also been recognized in other coeval basins of the Iberian Plate paleomargin, thus representing a bioevent of regional rank.ResumenObjetivoDescribir, por primera vez, las asociaciones de foraminíferos bentónicos registradas en materiales del intervalo comprendido entre la parte superior de la Zona Bradfordensis y la Zona Discites (límite Aaleniense–Bajociense, Jurásico Medio) en la sección de Barranco de Agua Larga (Cordillera Bética, sur de España), con el fin de inferir las condiciones paleoecológicas que condicionaron su desarrollo.MetodologíaSe analizó la composición de las asociaciones de foraminíferos registrados en 17 muestras recogidas en esta sección de referencia a lo largo del intervalo estratigráfico estudiado utilizando datos cuantitativos obtenidos a través de la estimación de abundancias relativas y del cálculo de varios índices de diversidad.ResultadosLas asociaciones son abundantes (se han obtenido un total de 3139 ejemplares bien conservados) y diversas (82 especies). Su composición muestra similitudes con asociaciones ya descritas en las plataformas carbonatadas jurásicas del Dominio Boreal (tipo A), Subdivisión Boreal Atlántica.ConclusionesLas asociaciones estudiadas se desarrollaron en condiciones ambientales marinas distales, a una profundidad situada por encima del nivel de compensación de la calcita, bien oxigenada y con salinidad normal, aunque en ciertos momentos pudieran haberse desarrollado condiciones ambientales desfavorables. Así, en el tránsito Aaleniense-Bajociense se registra una notable disminución en la abundancia y en la diversidad de las asociaciones registradas. Este evento, previamente reconocido en otras cuencas mesozoicas de la Placa Ibérica, tendría carácter regional.

OSTRACODS FROM THE GLOBAL STRATOTYPE SECTION FOR THE BASE OF THE AALENIAN STAGE, JURASSIC AT FUENTELSAZ SECTION(CORDILLERA IBÉRICA, SPAIN)

The Toarcian/Aalenian Global Stratotype Section and Point (GSSP) have been recently placed in the Fuentelsaz section, northeastern Spain. This paper is part of a long-term project that attempts to describe for the first time the fossil ostracod assemblages present in the Toarcian-Aalenian boundary GSSP, and to assess their palaeobiogeographical significance. The study of the Late Toarcian-Early Aalenian Turmiel and Casinos formations at the Fuentelsaz section has produced a detailed stratigraphy and a large collection of stratigraphically constrained ostracod faunas. Twenty benthic ostracod species have been identified and for the first time described in Spain. Higher part of the Mactra Subzone, Late Toarcian, have yielded abundant ostracod faunas, including mostly species of the genera Praeschuleridea , Cytherelloidea and Kinkelinella ; fossiliferous marls of the Late Toarcian and part of the Early Aalenian and poorly fossiliferous marls at the beginning of the Opalinum Zone are dominated by Praeschuleridea and Cytherelloidea . The boundary between the Toarcian and Aalenian is not characterized by any radical change in the ostracod faunal composition. The Fuentelsaz sequence exhibits ostracod assemblages comparable to those recorded in western Europe, with many of their species having similar stratigraphical distributions.

Response of benthic foraminiferal assemblages to contrasting environments during the Aalenian–Bajocian in the Iberia: a case study from the Talveila section (Iberian Range) and Murtinheira section (Lusitanian Basin)

This paper analyses the composition of the foraminiferal assemblages recorded in two different depositional contexts located in Iberia for the lower Aalenian–lower Bajocian stratigraphical interval: the Talveila section, corresponding to proximal facies within the Iberian Basin (NE Spain), and the Murtinheira section representing distal facies within the Lusitanian Basin (Western Portugal). The obtained specimens (10,736 in total) correspond to 6 suborders, 10 superfamilies, 16 families and 30 genera in Talveila, and 6 suborders, 9 superfamilies, 14 families and 26 genera in Murtinheira. Several biostratigraphic units based on the foraminiferal record and accurately calibrated with the ammonite record were recognized in both sections. Moreover, bioevents based on the first or last appearances of a taxon, significant changes in the abundance of one or several taxa or noticeable changes in diversity of the assemblages were also identified. The palaeoecological analysis shows that the foraminiferal assemblages from both sections were developed in a well-oxygenated and normal salinity shelf environment. The application of diversity indexes indicates that the paleoenvironmental conditions did not remain constant throughout the studied stratigraphic interval; changes recognized in both sections are similar, coeval and correspond to three intervals representing paleoenvironmental conditions more or less favourable for the development of the foraminiferal assemblages. As so, despite the different paleogeographical locations, the development of the assemblages in both sections during the Early Aalenian–Early Bajocian seem to have been conditioned by environmental changes of regional scale, which affected at the same time both the Iberian and the Lusitanian basins.ResumenEn este trabajo se analiza la composición de las asociaciones de foraminíferos registradas en dos contextos deposicionales diferentes, localizados en Iberia, para el intervalo estratigráfico Aaleniense inferior- Bajociense inferior. La sección de Talveila corresponde a facies proximales de la Cuenca Ibérica (NE España), y la sección de Murtinheira representa facies distales de la Cuenca Lusitánica (O de Portugal). Los ejemplares obtenidos (10736 en total) corresponden a 6 subórdenes, 10 superfamilias, 16 familias y 30 géneros en Talveila y 6 subórdenes, 9 superfamilias, 14 familias y 26 géneros en Murtinheira. Se han reconocido en ambas secciones algunas unidades bioestratigráficas basadas en el registro foraminíferos, y calibradas con precisión con el registro de ammonoideos. Además, se han identificado bioeventos basados en la primera o la última aparición de un taxón, cambios significativos en la abundancia de uno o varios taxones o cambios significativos en la diversidad de las asociaciones. El análisis paleoecológico realizado pone de manifiesto que en ambas secciones las asociaciones de foraminíferos se desarrollaron en un ambiente de plataforma bien oxigenada y con salinidad normal. Los resultados obtenidos tras la aplicación de varios índices de diversidad indican que las condiciones paleoambientales no fueron constantes durante todo el intervalo estratigráfico analizado; los cambios reconocidos en ambas secciones son similares y se corresponden con tres intervalos que representan condiciones paleoambientales más o menos favorables para el desarrollo de las asociaciones de foraminíferos. Por lo tanto, a pesar de las diferentes ubicaciones paleogeográficas de las secciones estudiadas, el desarrollo de las asociaciones en ambas durante el Aaleniense inferior - Bajociense inferior parece haber estado condicionado por cambios ambientales de escala regional, que afectaron tanto a la Cuenca Ibérica como a la Cuenca Lusitánica.

Accessible Geoparks in Iberia: a Challenge to Promote Geotourism and Education for Sustainable Development

This work aims at providing an overview regarding accessibility conditions for people with functional diversity among the 15 UNESCO Global Geoparks (UGGs) located in the Iberian Peninsula—4 in Portugal and 11 in Spain—from the point of view of a disabled user wishing to visit a geopark. Website information and a questionnaire composed of closed and multiple choice questions directly administrated to the geopark managers were used aiming at inquiring about facilities provided to people requiring adapted access conditions, including mobility, vision, hearing and cognitive dimensions of access both under the aim of geotourism activities or in the frame of educational programmes. Results show that Iberian UGGs display several facilities for the development of geotourism and education that meet the needs of people with functional diversity. Accessibility facilities to receive people with physical impairments are common, but sensory and communication access facilities are scarce. Geoparks’ websites generally lack information concerning facilities for special groups, and the web design does not meet the needs of people that have difficulties with written word and speech. The constraints on implementation of programmes aimed at disabled visitors can be partially overcome if geoparks’ leaders seek to integrate partners that currently develop activities for persons with disabilities. Geodivulgar (an innovation project from the Complutense University) and Science without Barriers (an association; Ciencia sin Barreras in Spanish) are pioneer initiatives for the outreach of geology among people with functional diversity in Spain, which currently develops activities and resources that can be of great help to enlarge the geoparks’ offer about geotouristic tours and/or educational programmes for disabled visitors. The acquired experience at the Basque Coast UGG can be of great help for other partners of the UGG Network to fully fulfil their roles as agents of sustainable development through geotourism and education for all.