Joan J. Fornós

Hypogene Imprints in Coastal Karst Caves from Mallorca Island (Western Mediterranean): Morphological Features and Speleogenetic Approach

The southern and eastern coasts of Mallorca Island (western Mediterranean) host abundant karst caves, some of them containing solutional features and deposits presumably related to hypogene basal recharge. The caves were formed in calcarenites whose ages range from Upper Miocene (reef deposits) to Middle Pleistocene (eolianites), which form a fringing postorogenic belt deposited over Mesozoic folded and thrusted carbonate deposits. The hydrogeological setting corresponds to an unconfined coastal aquifer in very porous eogenetic rocks, but showing important lateral and vertical permeability variations related to different sedimentary facies. Six caves containing hypogene features are distributed in three main coastal areas: the Llucmajor Upper Miocene platform, the Campos Plio-Pleistocene basin, and the Portocristo Upper Miocene littoral fringe. The first two areas are spatially coincident with low-grade geothermal anomalies reported in southern Mallorca, which are associated to important SW–NE faults. The observed cave features include a suite of solutional rising forms embracing, among others, subvertical feeder-like conduits and small ascending wall channels of variegated morphologies and dimensions. Sediments and black crusts enriched in Fe and Mn oxides are frequent along with some uncommon minerals, documenting a deep recharge rising into the unconfined littoral groundwater. Regarding their speleogenesis, the studied sites must be considered as complex littoral caves in which the imprints of hypogene processes are evident, but intermingled with other morphogenetic vectors like coastal mixing processes and a substantial meteoric recharge. The lithofacies variability of the carbonate rocks introduces additional complexity, affecting the hydrological behavior of the coastal aquifers as well as the pattern and morphology of the resulting caves.

Beach Systems of Balearic Islands: Nature, Distribution and Processes

The Balearic Islands coast contains 867 beach systems covering 10% of the coast reflecting the different controls of waves, sediments, geological inheritance and human disturbance. The average length of theses beaches are 169 m, raging from 10 m to more than 5 km, which implies that physical boundaries play a major role in beach length and morphology and wave attenuation; a moderate and seasonal wave climate and sediments composed predominantly of medium to coarse marine biogenic carbonate sands. It also describes the regional distribution, together with the occurrence of wave energy, beach sediments, bar systems and dynamics, rip currents, human disturbance and the influence of geological inheritance and marine biota.

Littoral Endokarst from Mallorca Island (Western Mediterranean)

Carbonate rocks are omnipresent in the case of the Balearic archipelago. This fact, together with an appropriate climatology, implies that karstic processes are the main responsible for the landscape development as well as the littoral shaping. The special geomorphological and hydrologic conditions of this area, along with sea-level, ecology, or paleoclimate, provokes a littoral complex interaction that give rise to a characteristic coastline. The objective of the present paper deals with the brief description of all related aspects of the endokarstic processes that affect the littoral fringe and summarizing their effects in the morphologic development of the coastline.

Sea level changes into MIS 5: From observations to predictions

Sea level history throughout the Quaternary shows a complex spatial and temporal pattern, and provides a globally averaged record of continental ice volume variations (Alley et al. 2005; Lambeck and Chappell 2001). Observations of this variability provide key constraints on the timing and amplitude of the forcing mechanisms that trigger the growth and decay of ice masses. With over a third of the world’s population living near coastlines, understanding the history and future impacts of global sea level change ranks as a top priority in the Earth sciences. As uncertainties are inherent to the methodologies and settings of all sea level reconstructions, there is a continued need for additional, independent sources of sea level data that may provide unique insights and crosschecks to the existing framework of former eustatic changes in sea level. The coastal caves of Mallorca with their unique speleothem encrustations (Fig. 1) provide one such source of additional sea level data (Tuccimei et al. 2012), which can be used to precisely document the elevation and timing of various sea level stands in the western Mediterranean region with sub-meter resolution (Dorale et al. 2010). The western Mediterranean was chosen as the workshop site so that participants (especially those working with corals, ice, or models) could visit the coastal caves of Mallorca and acquaint themselves with the setting of this promising approaches (Fig. 1). The purpose of the workshop was to bring together an international group of researchers to discuss and promote opportunities for collaboration on the topics of sea level data acquisition, calibration, and modeling. The meeting attracted 43 participants from nine countries, including 15 students and early career scientists. The workshop focused on the interpretation of sea level changes during marine isotope stage 5 (MIS 5) and the onset of MIS 4. The event was organized into three distinct sections: two days of presentations (both oral and poster), two days of field trips, and a half-day round table discussion that concluded the meeting and explored directions for future research. The first section included 20 oral presentations, of which six were invited keynotes, and nine were posters. The speakers covered a wide spectrum of problems pertinent to sea level changes, including detailed studies of reef and marine terraces, submerged speleothems, marine notches, marine sediment sequences, phreatic overgrowth on speleothems, flank margin caves, cave minerals, timing of MIS 5, Quaternary fauna, and advanced sea level modeling studies. Sea level modeling was a major focus of discussion during the round table, which tackled the following topics: (1) ways of reconciling controversial MIS 5a data sets from sea level fields around the world, (2) the use of glacio-hydro-isostasy modeling to address the issue above, (3) challenges in addressing past sea level positions and how the community should bridge the gap between field observation and models, and (4) observational and modeling constraints on sea level rise/fall and ice extent/volume. Finally, the workshop highlighted the interactions among researchers at various stages of their careers, from well-established scientists to junior faculty members, with particular emphasis on the participation of post-doctoral, undergraduate, and graduate students.