Joan J. Fornós

ABSTRACT Karren landforms developing on limestone rocks are understood to be produced primarily by chemical dissolutional processes. Available data suggest that rainfall intensity, drop size, water temperature and viscosity play significant roles in the growth of the most simple of these features, which are termed rillenkarren. Nevertheless, chemical data and scanning electron microscopy provided by our study have shown that mechanical removal of small limestone particles is one of the principal processes involved in the growth of rillenkarren. This mode of detachment is caused by the impact of raindrops but their effect seems greatly increased when algal cells of Chroococcus minutus (Kütz.) Näg. have previously corroded the surface of the limestone, weakening its crystalline structure. These fragile micromorphologies of biokarstic origin are fundamental in the development of rillenkarren, complementing the wellknown physico-chemical controls that are involved.

Global sea level and Earth’s climate are closely linked. Using speleothem encrustations from coastal caves on the island of Mallorca, we determined that western Mediterranean relative sea level was ~1 meter above modern sea level ~81,000 years ago during marine isotope stage (MIS) 5a. Although our findings seemingly conflict with the eustatic sea-level curve of far-field sites, they corroborate an alternative view that MIS 5a was at least as ice-free as the present, and they challenge the prevailing view of MIS 5 sea-level history and certain facets of ice-age theory.

... Dataciones Th/U de espeleotemas freáticos recolectados a cotas inferiores al actual nivel marino en cuevas costeras de Mallorca (España): Aportaciones a la construcción de una curva eustática detallada de los últimos 300 ka para el Mediterráneo occi. ...

ABSTRACT Karren landforms developing on limestone rocks are understood to be produced primarily by chemical dissolutional processes. Available data suggest that rainfall intensity, drop size, water temperature and viscosity play significant roles in the growth of the most simple of these features, which are termed rillenkarren. Nevertheless, chemical data and scanning electron microscopy provided by our study have shown that mechanical removal of small limestone particles is one of the principal processes involved in the growth of rillenkarren. This mode of detachment is caused by the impact of raindrops but their effect seems greatly increased when algal cells of Chroococcus minutus (Kütz.) Näg. have previously corroded the surface of the limestone, weakening its crystalline structure. These fragile micromorphologies of biokarstic origin are fundamental in the development of rillenkarren, complementing the wellknown physico-chemical controls that are involved.

Global sea level and Earth’s climate are closely linked. Using speleothem encrustations from coastal caves on the island of Mallorca, we determined that western Mediterranean relative sea level was ~1 meter above modern sea level ~81,000 years ago during marine isotope stage (MIS) 5a. Although our findings seemingly conflict with the eustatic sea-level curve of far-field sites, they corroborate an alternative view that MIS 5a was at least as ice-free as the present, and they challenge the prevailing view of MIS 5 sea-level history and certain facets of ice-age theory.

... Dataciones Th/U de espeleotemas freáticos recolectados a cotas inferiores al actual nivel marino en cuevas costeras de Mallorca (España): Aportaciones a la construcción de una curva eustática detallada de los últimos 300 ka para el Mediterráneo occi. ...