The 1852 and 1868 Mauna Loa picrite eruptions: Clues to parental magma compositions and the magmatic plumbing system

1995 ◽  
pp. 241-262 ◽  
Author(s):  
J. M. Rhodes
Keyword(s):  
Parental Magma ◽  
Plumbing System ◽  
Mauna Loa ◽  
Magma Compositions ◽  
Magmatic Plumbing System

scholarly journals Anatomy of the magmatic plumbing system of Los Humeros Caldera (Mexico): implications for geothermal systems

2019 ◽  
Author(s):  
Federico Lucci ◽  
Gerardo Carrasco-Núñez ◽  
Federico Rossetti ◽  
Thomas Theye ◽  
John C. White ◽  
...  
Keyword(s):  
Volcanic Belt ◽  
Mineral Chemistry ◽  
Volcanic Complex ◽  
Geothermal Systems ◽  
Plumbing System ◽  
Geothermal Exploration ◽  
Geothermal Fields ◽  
Mexican Volcanic Belt ◽  
Plumbing Systems ◽  
Magmatic Plumbing System

Abstract. Understanding the anatomy of magma plumbing systems of active volcanoes is essential not only for unraveling magma dynamics and eruptive behaviors, but also to define the geometry, depth and temperature of the heat sources for geothermal exploration. The Pleistocene-Holocene Los Humeros volcanic complex is part of the Eastern Trans-Mexican Volcanic Belt (Central Mexico) and it represents one of the most important exploited geothermal fields in Mexico with ca. 90 MW of produced electricity. A field-based petrologic and thermobarometric study of lavas erupted during the Holocene (post-Caldera stage) has been performed with the aim to decipher the anatomy of the magmatic plumbing system existing beneath the caldera. New petrographical, whole rock major element data and mineral chemistry were integrated within a suite of inverse thermobarometric models. Compared with previous studies where a single voluminous melt-controlled magma chamber (or "Standard Model") at shallow depths was proposed, our results support a more complex and realistic scenario characterized by a heterogeneous multilayered system comprising a deep (ca. 30 km) basaltic reservoir feeding progressively shallower and smaller distinct stagnation layers, pockets and batches up to very shallow conditions (1 kbar, ca. 3 km). Evolution of melts in the feeding system is mainly controlled by differentiation processes via fractional crystallization, as recorded by polybaric crystallization of clinopyroxenes and orthopyroxenes. Moreover, this study attempts to emphasize the importance to integrate field-petrography, texture observations and mineral chemistry of primary minerals to unravel the pre-eruptive dynamics and therefore the anatomy of the plumbing system beneath an active volcanic complex, which notwithstanding the numerous existing works is still far to be well understood. A better knowledge of the heat source feeding geothermal systems is very important to improve geothermal exploration strategies.

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