Search results for "PELE"

La movilidad humana, tema ineludible para la Iglesia Católica. Una estructura en constante tensión entre el imperativo de la acogida y la extrema com…

2017

Introducción -- La mayoría de las religiones que se practican en el mundo y casi la totalidad de las más populares contienen en sus mitos fundadores la memoria de una migración humana. La Biblia habla del peregrinar de Abraham (siglo XIX° AC) desde Mesopotamia a Palestina, del éxodo del pueblo judío de Egipto (siglo XIII° AC) y de la deportación de los Judíos a Babilonia (siglo VI° AC). Por su parte, Confucio forja sus pensamientos durante trece años, vagando entre los diversos reinos de la antigua China (siglos VI°-V° AC). En paralelo, el príncipe Siddhartha Gautama, o la versión histórica de Buda, sale de su palacio para descubrir el dolor y la frustración que imperan en el mundo (siglos …

Geoconservation in Sicily (Italy): the Example of the Isola delle Femmine (Palermo)

2022

Abstract The Regional Administration of Sicily recently erected Isola delle Femmine—a small island of the Tyrrhenian Sea, close to Palermo—as a geosite. A detailed geological survey has been carried out in order to define the most important geological features of the island together with the development of a new geological map based on topographic data and a digital model at 1:2.000 scale specially processed. Finally, a geological pathway through the island has been traced and illustrated. The geological substrate of Isola delle Femmine consists of a Mesozoic carbonate succession belonging to the Panormide Carbonate Platform. Two lithostratigraphic units have been differentiated. The lowest…

2019

Abstract. Here, we present the first quantitative speleothem record of lignin oxidation products (LOPs), which has been determined in a Holocene stalagmite from the Herbstlabyrinth Cave in central Germany. In addition, we present LOP results from 16 months of drip water monitoring. Lignin is only produced by vascular plants and therefore has the potential to be an unambiguous vegetation proxy and to complement other vegetation and climate proxies in speleothems. We compare our results with stable isotope and trace element data from the same sample. In the stalagmite, LOP concentrations show a similar behavior to P, Ba and U concentrations, which have previously been interpreted as vegetatio…

2020

Abstract. A compilation of the published literature on dust content in terrestrial and marine sediment cores was synchronized with pollen data and speleothem growth phases on the Greenland Ice Core Chronology 2005 (GICC05) time axis. Aridity patterns for eight key areas of the global climate system have been reconstructed for the last 60 000 years. These records have different time resolutions and different dating methods, i.e. different types of stratigraphy. Nevertheless, all regions analysed in this study show humid conditions during early Marine Isotope Stage 3 (MIS3) and the early Holocene or deglaciation, but not always at the same time. Such discrepancies have been interpreted as reg…

Climate and structure of the 8.2 ka event reconstructed from three speleothems from Germany

2020

Abstract The most pronounced climate anomaly of the Holocene was the 8.2 ka cooling event. We present new 230Th/U-ages as well as high-resolution stable isotope and trace element data from three stalagmites from two different cave systems in Germany, which provide important information about the structure and climate variability of the 8.2 ka event in central Europe. In all three speleothems, the 8.2 ka event is clearly recorded as a pronounced negative excursion of the δ18O values and can be divided into a ‘whole event’ and a ‘central event’. All stalagmites show a similar structure of the event with a short negative excursion prior to the ‘central event’, which marks the beginning of the …

New knowledge on the Monte Conca gypsum karst system (Central-western Sicily, Italy)

2011

The Monte Conca karst system is located in Central-Western Sicily, where Messinian evaporites are widespread. Here, the evaporites lie on lower Messinian-middle Serravallian clayey-marly-sandy deposits and are overlain locally by Pliocene marly limestones. These successions are affected by E-W, and to a lesser degree N-S and NW-SE, high-angle faults that have also produced lateral contacts between the gypsum units and the clayey-marly deposits. The cave passages reachaltogether about 2.4 km in lengthand 130 m in depth, and the system consists of a sink cave, a resurgence and a relict resurgence. At large scale it is characterized by superimposed levels of sub-horizontal galleries connected …

Acqua Fitusa cave: An example of inactive water-table sulphuric acid cave in Central Sicily

2012

Description of the sulphuric acid cave in Sicily (see pdf attached)

Modelling fractionation of stable isotopes in stalagmites

2009

Abstract High resolution δ13C and δ18O profiles recorded in precisely dated speleothems are widely used proxies for the climate of the past. Both δ13C and δ18O depend on several climate related effects including meteorological processes, processes occurring in the soil zone above the cave and isotope fractionation processes occurring in the solution layer on the stalagmite surface. Here we model the latter using a stalagmite isotope and growth model and determine the relationship between the stable isotope values in speleothem calcite and cave parameters, such as temperature, drip interval, water p CO 2 and a mixing coefficient describing mixing processes between the solution layer and the …

Monitoring Bunker Cave (NW Germany): A prerequisite to interpret geochemical proxy data of speleothems from this site

2011

Summary Monitoring cave environments is important to understand processes in karst systems. If stalagmites from a specific cave are used as archives of past climate variability, a quantitative understanding of the soil–karst–speleothem system is crucial. The monitoring program performed in Bunker Cave (NW Germany), which includes monthly collection of climatological data as well as air and water samples from the cave and the overlying soil since 2006, is a prerequisite for the interpretation of speleothem data from the cave in terms of climate variability. The results show that Bunker Cave is a homogeneously ventilated cave with rather low pCO2 values of 580–1200 ppmv, which lacks strong se…

Carbon isotope exchange between gaseous CO2 and thin solution films: Artificial cave experiments and a complete diffusion-reaction model

2017

Abstract Speleothem stable carbon isotope (δ 13 C) records provide important paleoclimate and paleo-environmental information. However, the interpretation of these records in terms of past climate or environmental change remains challenging because of various processes affecting the δ 13 C signals. A process that has only been sparsely discussed so far is carbon isotope exchange between the gaseous CO 2 of the cave atmosphere and the dissolved inorganic carbon (DIC) contained in the thin solution film on the speleothem, which may be particularly important for strongly ventilated caves. Here we present a novel, complete reaction diffusion model describing carbon isotope exchange between gase…