Bernadí Gelabert

A structural outline of the Serra de Tramuntana of Mallorca (Balearic Islands)

Abstract The structural and stratigraphic aspects of the Balearic Islands are described by outlining the geology of the Serra de Tramuntana. This range is part of the southeastern margin of the Valencia trough and has the typical features of thrust tectonic areas. A stratigraphic column, a structural map and three cross-sections show the main features of this range. Thrusts dip to the southeast and are arranged in an imbricate system with a transport direction to the NW. The thrusts recorded involve Upper Paleozoic to Middle Miocene rocks. Imbricates-bearing thin slices and duplexes developed where thin sequences with pronounced competency contrasts exist. Folds are also present: they usually trend NE-SW, except in local areas where they are interpreted as being associated with oblique ramps. Fold axes plunge sub-horizontally and folds face the northwest. Thrust displacements of up to 10 km are deduced from the existence of klippes and windows, and shortening of around 50% is deduced from a comparison of deformed and restored cross-sections. The onset of the main contractional event is pre-Miocene (probably Late Oligocene) in age, but major thrust emplacement occurred during the Middle Miocene. The widespread occurrence of compression structures in the Balearic Islands developed from late Oligocene to Middle Miocene put strong constraints on the models explaining the origin of both the Valencia trough and the Algerian basin. The first must be considered, at least in part, as the Balearic foreland basin and the second could be superimposed on the internal zone of the western Mediterranean orogenic belt.

Geomorphological characteristics and slope processes associated with different basins: Mallorca (Western Mediterranean)

Abstract We compare the different geomorphological processes which occurred in Pliocene–Quaternary times on two very similar slopes in Mallorca, one located at the Tramuntana Range and the other in the Llevant Ranges. Both slopes have the same geological structure, the same stratigraphic and lithological levels, and the same altitude and orientation. The different slope processes are due to the relationship between the accommodation space and the sedimentation rate in the adjacent basins: In the Valencia Trough (located N of the Tramuntana Range), the sedimentation rate has not been sufficient to fill the accommodation space, whereas in the Alcudia Basin (adjacent to the Llevant Ranges), the sedimentation rate has been sufficient to fill the accommodation space. This difference has resulted in major landslides on the Tramuntana slope, whereas the Llevant slope is characterized mainly by alluvial fans and debris screes.

Significance of Inherited Normal Faults during Inversion Tectonics: an example from the Tramuntana Range, Mallorca

The Late Oligocene-Middle Miocene Mallorca fold-and-thrust belt is characterised by a large amount of shortening above a detachment horizon. A regional section of 50 km in length across the island shows shortening of 80 km. Nevertheless, earlier normal faults play a significant role in compressive deformation. Two examples illustrating their role are presented: the first example is a fault-propagation-fold nucleated on a normal fault located in the fold core. We present a simple numerical model of this structure that illustrates how the observed complex structural and stratigraphic geometries might develop. The second example is a normal fault that interrupts the detachment level, giving rise to a step that results in a back-thrust system.

Beaches of Ibiza and Formentera (Balearic Islands): a classification based on their environmental features, tourism use and management

ABSTRACT Roig-Munar, F.X., Mir-Gual, M., Rodríguez-Perea, A., Pons, G.X., Martín-Prieto, J.A., Gelabert, B. and Blázquez, M., 2013. Beaches of Ibiza and Formentera (Balearic Islands): a classification based on their environmental features, tourism use and management, In order to define their character a total of 100 beaches of Ibiza (76) and Formentera (24) are analyzed on the basis of 35 variables of beach use, state and management. We take as a reference a primary classification where three types of beaches have been considered; urban beaches (A), semi-natural beaches with urban features (B), and natural beaches (C). Departing from this scenario, and taking into account the identified variables, statistical analysis (Cluster and PCA analysis) have been done in the sense of identifying the current state of each beach and the differences among them. Currently many of the beaches of Ibiza are urban beaches (A). Furthermore the results suggest a potential trend that some of natural beaches (B-C) can become to A type in the next future. Understanding this classification, and also the recent history of the management applied in the study units, allow predicting trend scenarios. In this sense, management changes should be proposed in order to improve their current situation, and drive them toward a better conservation status.

Coastal Management in the Balearic Islands

Coastal dunes represent important natural systems for balancing the beach while providing different functions such as protection against erosion and important ecological niches.