What are the Maccalube of Aragon

The Maccalube of Aragon are the most? relevant in Sicily of the so-called sedimentary volcanism, cos? defined by morphological analogy with the volcanic one strictu sensu, which consists in the coming to light of natural gases which, carrying water and clay, form on the surface characteristic mud volcanoes (or small volcanoes), of variable height.
The Maccalube of Aragon are the most? relevant in Sicily of the so-called sedimentary volcanism, cos? defined by morphological analogy with the volcanic one strictu sensu, which consists in the coming to light of natural gases which, carrying water and clay, form on the surface characteristic mud volcanoes (or small volcanoes), of variable height.
The engine of the ascent of fluids? to be found in two main forces: the buoyancy of the buried sediments and the interstitial pressure of the fluids within the sediments themselves. The vulcanello-maccalube fluids contained in the interstitial pores can generate internal overpressures which, in some cases, are higher than the pressure exerted by the load of the overlying rocks. When we? occurs, the buried and unconsolidated material has sufficient thrust to reach the surface with energy, giving rise to real mud cones. In some cases, the energy involved? such as to give rise to violent and sudden eruptions similar to ?mud fountains?, which can be detected by monitoring instruments (see the article ?The Maccalube mud volcano recorded by the National Seismic Network? on http://ingvterremoti.wordpress.com). The interstitial waters present in the Maccalube di Aragona system have marine origin, and are formed following the compaction of sediments in a tectonic environment dominated by compressive thrusts. The gas more abundant ? methane (CH4) with concentrations of up to 97% by volume. Nitrogen (N2), oxygen (O2) and carbon dioxide (CO2) are present in varying concentrations as secondary components. Other gaseous hydrocarbons pi? heavy gases (ethane and propane) are present in concentrations in the hundreds or thousands of parts per million (ppm). Furthermore, the presence of helium (He) in concentrations in the order of hundreds of ppm with an isotope ratio of about 0.7 Ra, indicates a non-negligible contribution (about 10%) of outgassing from the earth's mantle, suggesting the existence of a zone of crustal weakness of a regional nature that goes up to high depth.

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