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Papers by Andrea Tranquilli
Updates in Volcanology - A Comprehensive Approach to Volcanological Problems, 2012
The CVF volcanoes occur in a circular area of about 3000 km 2 , at the western termination of the... more The CVF volcanoes occur in a circular area of about 3000 km 2 , at the western termination of the SSW-NNE elongated Guadiana valley (Fig. 1), which is one of the largest tectonic basins in central-southern Spain. Most of the CVF centres are nested in the Palaeozoic rocks of the Calatrava and Almagro massifs, composed of quartzite, slate and lesser granite, deformed in E-W and N-S vertical, flexural folds (De Vicente et al., 2007). The massifs are cut by faults striking NW-SE and E-W, which determine a low profile, "horst and graben"-type morphology. The CVF has been subject to a generalised uplift that produced erosion of the www.intechopen.com
Journal of Volcanology and Geothermal Research, 2011
Pelletal and spinning lapilli as well as concentric-shelled lapilli-bombs are present in ultra-al... more Pelletal and spinning lapilli as well as concentric-shelled lapilli-bombs are present in ultra-alkaline rocks worldwide. There are well-established models for generation of those pyroclasts in diatreme conduit leading to the formation of subvolcanic pyroclastic rocks, i.e. tuffisites, by diatremic fluidisation. In contrast, Carracedo Sanchez et al. (2009) introduced a completely different model for all the above pyroclasts, and composite (concentric-shelled) bombs in particular, in the strombolian deposits of Cabezo Segura II (CS-II), Calatrava, Spain. In their model the pyroclasts are formed in a strombolian eruptive column. On the basis of our observations and physical-chemical constraints, we contend that this model is not feasible. The Authors' (AA) model requires agglutination/accretion by sintering in the eruption column, keeping the particles in a partially molten state. We find that composite bombs from CS-II show evidence for very rapid quenching of the melt preventing sintering, which in any case is impossible in a convective region where the temperature will be reduced below the solidus of the melt. Analysis of terminal velocity indicates that it would be possible to transport pelletal lapilli in a strombolian thrust region, but dense (between 2.25 and 2.85 g/cm 3) lapilli and bombs cannot reach a convective region (stage 3 of the AA's model), which in any case is unlikely to exist at CS-II. By contrast, pelletal-, spinning-and concentric-shelled lapilli and composite bombs can be erupted, but their formation does not depend on the surficial extrusion mechanism. The presence of carbonatite at CS-II indicates juvenile CO 2 to be fundamental and indicative of diatremic fluidisation. Concentric-shelled bombs composed of agglutinated pelletal-and spinning-lapilli are interpreted as a development in the upper diatreme.
This guide book is intended for those who want general information about Lanzarote and 1730-1736 ... more This guide book is intended for those who want general information about Lanzarote and 1730-1736 Timanfaya eruption. Lanzarote was declared Reserve of the Biosphere in 1993 by the UNESCO. Lanzarote has a fragile territory with unique landscape treated by densely inhabited areas of growing globalising tourist industry. To be a Reserve of the Biosphere means to make evident the conflict between preservation and development, between local and imported models of development, short and long term and between public goods and private interest. Lanzarote has to faces up to the own contradictions. A strong contribute comes from the ideas of César Manrique (1919-1992). He was a painter, sculptor, architect, ecologist, natural monument preserver, construction advisor, planner of urban developments, outliner of landscapes and gardens. For César Manrique, volcanic nature of Lanzarote was the fundamental reference of his work and his existence and to the end of his days he managed to maintain a p...
ABSTRACT We compare the mineralogy of carbonates on Mars and terrestrial carbonatites using XRD a... more ABSTRACT We compare the mineralogy of carbonates on Mars and terrestrial carbonatites using XRD and reflectance spectroscopy to unravel the origin of carbonates on Mars.
ABSTRACT The most common cause of carbonates formation on Earth is the chemical deposition from C... more ABSTRACT The most common cause of carbonates formation on Earth is the chemical deposition from Ca-rich waters in sedimentary basins, mostly in shallow water. The lack of widespread exposure of carbonates on the Mars' surface in areas where geomorphological and sedimentological mapping confirms the presence of water for a long period of the Martian history, led us to look for a potential different origin of the carbonates identified on CRISM data [1, 2,3]. We suggest the presence of carbonatites on Mars and we have also investigated the capabilities of analytical tecniques for mineralogical analysis to recognise these peculiar type of rocks. Carbonatites are igneous rocks containing more than 50 percent of carbonate minerals and associated silicate minerals as olivine, pyroxene and phyllosilicates. Carbonatites are associated with alkali silicate rocks that are usually of nephelinitic or melilititic affinity. The Martian carbonates are often present in layered rocks and in association with hydrated Fe-Mg silicates (clays family) and kaolinite-group minerals at places [1]. This mineralogical association is very similar to an water-altered carbonatite. We have compared the compositional and mineralogical affinity of some carbonatite samples from different alkaline-carbonatite complexes from Uganda, Spain and Italy, with the mineralogy described for the carbonate- and phyllosolicate rich rocks on Mars, using the XRD and IR analyses. The mineral assemblage has been defined through petrographic analyses as well. It is important to stress that only with XRD analysis some minerals diagnos-tic of carbonatitic assemblage (i.e. melilite) were identified. The relationships between carbonatites and their associated silicate rocks are complex and are still not fully understood on Earth as well, however, it deserves further investigations to better explain the carbonates and silicate volcanic rocks on Mars and its crustal dynamics. References: [1] Michalski and Niles, 2010, Nature Geoscience, 751-755. [2] Helmann et al., 2008, Science, 322, 1828-1832. [3] Morris et al., 2010, Science, 329, 421-424.
Updates in Volcanology - A Comprehensive Approach to Volcanological Problems, 2012
Journal of Volcanology and Geothermal Research, 2011
Pelletal and spinning lapilli as well as concentric-shelled lapilli-bombs are present in ultra-al... more Pelletal and spinning lapilli as well as concentric-shelled lapilli-bombs are present in ultra-alkaline rocks worldwide. There are well-established models for generation of those pyroclasts in diatreme conduit leading to the formation of subvolcanic pyroclastic rocks, i.e. tuffisites, by diatremic fluidisation. In contrast, Carracedo Sanchez et al. (2009) introduced a completely different model for all the above pyroclasts, and composite (concentric-shelled) bombs in particular, in the strombolian deposits of Cabezo Segura II (CS-II), Calatrava, Spain. In their model the pyroclasts are formed in a strombolian eruptive column. On the basis of our observations and physical-chemical constraints, we contend that this model is not feasible. The Authors' (AA) model requires agglutination/accretion by sintering in the eruption column, keeping the particles in a partially molten state. We find that composite bombs from CS-II show evidence for very rapid quenching of the melt preventing sintering, which in any case is impossible in a convective region where the temperature will be reduced below the solidus of the melt. Analysis of terminal velocity indicates that it would be possible to transport pelletal lapilli in a strombolian thrust region, but dense (between 2.25 and 2.85 g/cm 3 ) lapilli and bombs cannot reach a convective region (stage 3 of the AA's model), which in any case is unlikely to exist at CS-II. By contrast, pelletal-, spinning-and concentric-shelled lapilli and composite bombs can be erupted, but their formation does not depend on the surficial extrusion mechanism. The presence of carbonatite at CS-II indicates juvenile CO 2 to be fundamental and indicative of diatremic fluidisation. Concentric-shelled bombs composed of agglutinated pelletal-and spinning-lapilli are interpreted as a development in the upper diatreme.
This guide book is intended for those who want general information about Lanzarote and 1730-1736 ... more This guide book is intended for those who want general information about Lanzarote and 1730-1736 Timanfaya eruption. Lanzarote was declared Reserve of the Biosphere in 1993 by the UNESCO. Lanzarote has a fragile territory with unique landscape treated by densely inhabited areas of growing globalising tourist industry. To be a Reserve of the Biosphere means to make evident the conflict between preservation and development, between local and imported models of development, short and long term and between public goods and private interest. Lanzarote has to faces up to the own contradictions. A strong contribute comes from the ideas of César Manrique (1919-1992). He was a painter, sculptor, architect, ecologist, natural monument preserver, construction advisor, planner of urban developments, outliner of landscapes and gardens. For César Manrique, volcanic nature of Lanzarote was the fundamental reference of his work and his existence and to the end of his days he managed to maintain a p...
Updates in Volcanology - A Comprehensive Approach to Volcanological Problems, 2012
The CVF volcanoes occur in a circular area of about 3000 km 2 , at the western termination of the... more The CVF volcanoes occur in a circular area of about 3000 km 2 , at the western termination of the SSW-NNE elongated Guadiana valley (Fig. 1), which is one of the largest tectonic basins in central-southern Spain. Most of the CVF centres are nested in the Palaeozoic rocks of the Calatrava and Almagro massifs, composed of quartzite, slate and lesser granite, deformed in E-W and N-S vertical, flexural folds (De Vicente et al., 2007). The massifs are cut by faults striking NW-SE and E-W, which determine a low profile, "horst and graben"-type morphology. The CVF has been subject to a generalised uplift that produced erosion of the www.intechopen.com
Journal of Volcanology and Geothermal Research, 2011
Pelletal and spinning lapilli as well as concentric-shelled lapilli-bombs are present in ultra-al... more Pelletal and spinning lapilli as well as concentric-shelled lapilli-bombs are present in ultra-alkaline rocks worldwide. There are well-established models for generation of those pyroclasts in diatreme conduit leading to the formation of subvolcanic pyroclastic rocks, i.e. tuffisites, by diatremic fluidisation. In contrast, Carracedo Sanchez et al. (2009) introduced a completely different model for all the above pyroclasts, and composite (concentric-shelled) bombs in particular, in the strombolian deposits of Cabezo Segura II (CS-II), Calatrava, Spain. In their model the pyroclasts are formed in a strombolian eruptive column. On the basis of our observations and physical-chemical constraints, we contend that this model is not feasible. The Authors' (AA) model requires agglutination/accretion by sintering in the eruption column, keeping the particles in a partially molten state. We find that composite bombs from CS-II show evidence for very rapid quenching of the melt preventing sintering, which in any case is impossible in a convective region where the temperature will be reduced below the solidus of the melt. Analysis of terminal velocity indicates that it would be possible to transport pelletal lapilli in a strombolian thrust region, but dense (between 2.25 and 2.85 g/cm 3) lapilli and bombs cannot reach a convective region (stage 3 of the AA's model), which in any case is unlikely to exist at CS-II. By contrast, pelletal-, spinning-and concentric-shelled lapilli and composite bombs can be erupted, but their formation does not depend on the surficial extrusion mechanism. The presence of carbonatite at CS-II indicates juvenile CO 2 to be fundamental and indicative of diatremic fluidisation. Concentric-shelled bombs composed of agglutinated pelletal-and spinning-lapilli are interpreted as a development in the upper diatreme.
This guide book is intended for those who want general information about Lanzarote and 1730-1736 ... more This guide book is intended for those who want general information about Lanzarote and 1730-1736 Timanfaya eruption. Lanzarote was declared Reserve of the Biosphere in 1993 by the UNESCO. Lanzarote has a fragile territory with unique landscape treated by densely inhabited areas of growing globalising tourist industry. To be a Reserve of the Biosphere means to make evident the conflict between preservation and development, between local and imported models of development, short and long term and between public goods and private interest. Lanzarote has to faces up to the own contradictions. A strong contribute comes from the ideas of César Manrique (1919-1992). He was a painter, sculptor, architect, ecologist, natural monument preserver, construction advisor, planner of urban developments, outliner of landscapes and gardens. For César Manrique, volcanic nature of Lanzarote was the fundamental reference of his work and his existence and to the end of his days he managed to maintain a p...
ABSTRACT We compare the mineralogy of carbonates on Mars and terrestrial carbonatites using XRD a... more ABSTRACT We compare the mineralogy of carbonates on Mars and terrestrial carbonatites using XRD and reflectance spectroscopy to unravel the origin of carbonates on Mars.
ABSTRACT The most common cause of carbonates formation on Earth is the chemical deposition from C... more ABSTRACT The most common cause of carbonates formation on Earth is the chemical deposition from Ca-rich waters in sedimentary basins, mostly in shallow water. The lack of widespread exposure of carbonates on the Mars' surface in areas where geomorphological and sedimentological mapping confirms the presence of water for a long period of the Martian history, led us to look for a potential different origin of the carbonates identified on CRISM data [1, 2,3]. We suggest the presence of carbonatites on Mars and we have also investigated the capabilities of analytical tecniques for mineralogical analysis to recognise these peculiar type of rocks. Carbonatites are igneous rocks containing more than 50 percent of carbonate minerals and associated silicate minerals as olivine, pyroxene and phyllosilicates. Carbonatites are associated with alkali silicate rocks that are usually of nephelinitic or melilititic affinity. The Martian carbonates are often present in layered rocks and in association with hydrated Fe-Mg silicates (clays family) and kaolinite-group minerals at places [1]. This mineralogical association is very similar to an water-altered carbonatite. We have compared the compositional and mineralogical affinity of some carbonatite samples from different alkaline-carbonatite complexes from Uganda, Spain and Italy, with the mineralogy described for the carbonate- and phyllosolicate rich rocks on Mars, using the XRD and IR analyses. The mineral assemblage has been defined through petrographic analyses as well. It is important to stress that only with XRD analysis some minerals diagnos-tic of carbonatitic assemblage (i.e. melilite) were identified. The relationships between carbonatites and their associated silicate rocks are complex and are still not fully understood on Earth as well, however, it deserves further investigations to better explain the carbonates and silicate volcanic rocks on Mars and its crustal dynamics. References: [1] Michalski and Niles, 2010, Nature Geoscience, 751-755. [2] Helmann et al., 2008, Science, 322, 1828-1832. [3] Morris et al., 2010, Science, 329, 421-424.
Updates in Volcanology - A Comprehensive Approach to Volcanological Problems, 2012
Journal of Volcanology and Geothermal Research, 2011
Pelletal and spinning lapilli as well as concentric-shelled lapilli-bombs are present in ultra-al... more Pelletal and spinning lapilli as well as concentric-shelled lapilli-bombs are present in ultra-alkaline rocks worldwide. There are well-established models for generation of those pyroclasts in diatreme conduit leading to the formation of subvolcanic pyroclastic rocks, i.e. tuffisites, by diatremic fluidisation. In contrast, Carracedo Sanchez et al. (2009) introduced a completely different model for all the above pyroclasts, and composite (concentric-shelled) bombs in particular, in the strombolian deposits of Cabezo Segura II (CS-II), Calatrava, Spain. In their model the pyroclasts are formed in a strombolian eruptive column. On the basis of our observations and physical-chemical constraints, we contend that this model is not feasible. The Authors' (AA) model requires agglutination/accretion by sintering in the eruption column, keeping the particles in a partially molten state. We find that composite bombs from CS-II show evidence for very rapid quenching of the melt preventing sintering, which in any case is impossible in a convective region where the temperature will be reduced below the solidus of the melt. Analysis of terminal velocity indicates that it would be possible to transport pelletal lapilli in a strombolian thrust region, but dense (between 2.25 and 2.85 g/cm 3 ) lapilli and bombs cannot reach a convective region (stage 3 of the AA's model), which in any case is unlikely to exist at CS-II. By contrast, pelletal-, spinning-and concentric-shelled lapilli and composite bombs can be erupted, but their formation does not depend on the surficial extrusion mechanism. The presence of carbonatite at CS-II indicates juvenile CO 2 to be fundamental and indicative of diatremic fluidisation. Concentric-shelled bombs composed of agglutinated pelletal-and spinning-lapilli are interpreted as a development in the upper diatreme.
This guide book is intended for those who want general information about Lanzarote and 1730-1736 ... more This guide book is intended for those who want general information about Lanzarote and 1730-1736 Timanfaya eruption. Lanzarote was declared Reserve of the Biosphere in 1993 by the UNESCO. Lanzarote has a fragile territory with unique landscape treated by densely inhabited areas of growing globalising tourist industry. To be a Reserve of the Biosphere means to make evident the conflict between preservation and development, between local and imported models of development, short and long term and between public goods and private interest. Lanzarote has to faces up to the own contradictions. A strong contribute comes from the ideas of César Manrique (1919-1992). He was a painter, sculptor, architect, ecologist, natural monument preserver, construction advisor, planner of urban developments, outliner of landscapes and gardens. For César Manrique, volcanic nature of Lanzarote was the fundamental reference of his work and his existence and to the end of his days he managed to maintain a p...