Las Cabras volcano, Michoacán-Guanajuato Volcanic Field, México: Topographic, climatic, and shallow magmatic controls on scoria cone eruptions
Scoria cones are abundant in most volcanic fields on Earth, such as the Michoacán-Guanajuato Volcanic Field, in the central-western sector of the Trans-Mexican Volcanic Belt. However, there are few in-depth studies on their eruptive style and controlling factors, despite of their diversity in shape...
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Universidad Nacional Autónoma de México
2021-07-01
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| Online Access: | https://rmcg.unam.mx/index.php/rmcg/article/view/1645 |
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| author | Marie-Noëlle Guilbaud Athziri Hernández-Jiménez Claus Siebe Sergio Salinas |
| author_facet | Marie-Noëlle Guilbaud Athziri Hernández-Jiménez Claus Siebe Sergio Salinas |
| author_sort | Marie-Noëlle Guilbaud |
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Scoria cones are abundant in most volcanic fields on Earth, such as the Michoacán-Guanajuato Volcanic Field, in the central-western sector of the Trans-Mexican Volcanic Belt. However, there are few in-depth studies on their eruptive style and controlling factors, despite of their diversity in shape and composition which implies a wide range of hazards. Here, we present results of morphologic, stratigraphic, sedimentary, petrographic, and geochemical studies of the prominent Las Cabras scoria cone located west of the Zacapu lacustrine basin in the center of the Michoacán-Guanajuato Volcanic Field. This basaltic andesitic to andesitic volcano formed between 27 and 26 kyrs BP on the steep slopes (>10º) of the lava shield of El Tule volcano. Over time, its dominant eruptive style changed from Strombolian to effusive. Initial explosive activity built a 170-m-high scoria cone and deposited thick tephra fallout on the surrounding sloping terrain. Structures in the deposits indicate that early friable fine-grained tephra underwent significant erosion due to syn-eruptive heavy rain coupled with the sloping nature of the underlying ground. This erosion generated lahars that very likely reached the Zacapu lake based on the pre-eruptive topography. As the explosivity dropped, lava was emitted from the base of the cone first to the S and SE, forming a thick, viscous lobe that filled a pre-existing E-W valley. The flow direction then deviated to the N and NE, to form thinner, less-viscous lobes fed from the vent by an open-channel. The lavas are covered by hummocks made of agglutinates and bombs that indicate that the eruption terminated by catastrophic collapse of the SE sector of the cone, possibly triggered by the intrusion of magma within the cone, which destabilized its downslope segment. The sudden flank failure was potentially associated with a late effusive event and the hummocks may have been carried away by the lava surge. Whole-rock chemical variations and crystal disequilibrium textures point toward a complex magma feeding system, involving mixing and mingling between different magma batches. This study shows that the formation of scoria cones on a terrain with a marked slope (>10°) has profound impacts on the eruption dynamics and related hazards due to its effect on cone stability and ash erosion. It also evidences the erosive effect of syn-eruptive rain on fine-grained tephra, especially when deposited on a slope. Finally, it reveals the complex magmatic processes that may occur in the shallow plumbing system of monogenetic andesitic volcanoes, which could be particularly important in inland areas of continental arcs.
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| format | Article |
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| institution | Kabale University |
| issn | 1026-8774 2007-2902 |
| language | English |
| publishDate | 2021-07-01 |
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| series | Revista Mexicana de Ciencias Geológicas |
| spelling | doaj-art-66e577b3ecb44b34a7eb8cdc8fadf7cc2025-08-20T03:25:33ZengUniversidad Nacional Autónoma de MéxicoRevista Mexicana de Ciencias Geológicas1026-87742007-29022021-07-0138210.22201/cgeo.20072902e.2021.2.1645Las Cabras volcano, Michoacán-Guanajuato Volcanic Field, México: Topographic, climatic, and shallow magmatic controls on scoria cone eruptionsMarie-Noëlle Guilbaud0Athziri Hernández-Jiménez1Claus Siebe2Sergio Salinas3Departamento de Vulcanología, Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, C.P. 04510 Coyoacán, Mexico City, Mexico.Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, C.P. 04510 Coyoacán, Mexico City, Mexico.Departamento de Vulcanología, Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, C.P. 04510 Coyoacán, Mexico City, Mexico.Facultad de Ingeniería, División de Ingeniería en Ciencias de la Tierra, Universidad Nacional Autónoma de México, Ciudad Universitaria, C.P. 04510 Coyoacán, Mexico City, Mexico. Scoria cones are abundant in most volcanic fields on Earth, such as the Michoacán-Guanajuato Volcanic Field, in the central-western sector of the Trans-Mexican Volcanic Belt. However, there are few in-depth studies on their eruptive style and controlling factors, despite of their diversity in shape and composition which implies a wide range of hazards. Here, we present results of morphologic, stratigraphic, sedimentary, petrographic, and geochemical studies of the prominent Las Cabras scoria cone located west of the Zacapu lacustrine basin in the center of the Michoacán-Guanajuato Volcanic Field. This basaltic andesitic to andesitic volcano formed between 27 and 26 kyrs BP on the steep slopes (>10º) of the lava shield of El Tule volcano. Over time, its dominant eruptive style changed from Strombolian to effusive. Initial explosive activity built a 170-m-high scoria cone and deposited thick tephra fallout on the surrounding sloping terrain. Structures in the deposits indicate that early friable fine-grained tephra underwent significant erosion due to syn-eruptive heavy rain coupled with the sloping nature of the underlying ground. This erosion generated lahars that very likely reached the Zacapu lake based on the pre-eruptive topography. As the explosivity dropped, lava was emitted from the base of the cone first to the S and SE, forming a thick, viscous lobe that filled a pre-existing E-W valley. The flow direction then deviated to the N and NE, to form thinner, less-viscous lobes fed from the vent by an open-channel. The lavas are covered by hummocks made of agglutinates and bombs that indicate that the eruption terminated by catastrophic collapse of the SE sector of the cone, possibly triggered by the intrusion of magma within the cone, which destabilized its downslope segment. The sudden flank failure was potentially associated with a late effusive event and the hummocks may have been carried away by the lava surge. Whole-rock chemical variations and crystal disequilibrium textures point toward a complex magma feeding system, involving mixing and mingling between different magma batches. This study shows that the formation of scoria cones on a terrain with a marked slope (>10°) has profound impacts on the eruption dynamics and related hazards due to its effect on cone stability and ash erosion. It also evidences the erosive effect of syn-eruptive rain on fine-grained tephra, especially when deposited on a slope. Finally, it reveals the complex magmatic processes that may occur in the shallow plumbing system of monogenetic andesitic volcanoes, which could be particularly important in inland areas of continental arcs. https://rmcg.unam.mx/index.php/rmcg/article/view/1645Monogeneticscoria conesslopetephraerosionmagma mixing |
| spellingShingle | Marie-Noëlle Guilbaud Athziri Hernández-Jiménez Claus Siebe Sergio Salinas Las Cabras volcano, Michoacán-Guanajuato Volcanic Field, México: Topographic, climatic, and shallow magmatic controls on scoria cone eruptions Revista Mexicana de Ciencias Geológicas Monogenetic scoria cones slope tephra erosion magma mixing |
| title | Las Cabras volcano, Michoacán-Guanajuato Volcanic Field, México: Topographic, climatic, and shallow magmatic controls on scoria cone eruptions |
| title_full | Las Cabras volcano, Michoacán-Guanajuato Volcanic Field, México: Topographic, climatic, and shallow magmatic controls on scoria cone eruptions |
| title_fullStr | Las Cabras volcano, Michoacán-Guanajuato Volcanic Field, México: Topographic, climatic, and shallow magmatic controls on scoria cone eruptions |
| title_full_unstemmed | Las Cabras volcano, Michoacán-Guanajuato Volcanic Field, México: Topographic, climatic, and shallow magmatic controls on scoria cone eruptions |
| title_short | Las Cabras volcano, Michoacán-Guanajuato Volcanic Field, México: Topographic, climatic, and shallow magmatic controls on scoria cone eruptions |
| title_sort | las cabras volcano michoacan guanajuato volcanic field mexico topographic climatic and shallow magmatic controls on scoria cone eruptions |
| topic | Monogenetic scoria cones slope tephra erosion magma mixing |
| url | https://rmcg.unam.mx/index.php/rmcg/article/view/1645 |
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