Common characteristics of paired volcanoes in northern Central America

Abstract

Four pairs of active volcanoes along the northern Central American volcanic front have erupted basalt‐andesite magmas that show consistent intrapair behavioral and compositional differences. These differences are found in records of volcanic activity and complete major and minor element data on over 200 samples. From northwest to southeast along the volcanic front the four volcano pairs are Cerro Quemado‐Santa María, Tolimán‐Atitlán, Acatenango‐Fuego, and Santa Ana‐Izalco. The volcano pair relations help explain compositional differences, apart from those reflecting variation in crustal thickness of about 15 km along the volcanic front, providing insight into across‐arc variations and closely spaced subvolcanic plumbing systems. Intravolcano pair spacing is less than 5 km compared with an average intervolcano spacing of 25 km along the entire volcanic front. Within each volcano pair, the seaward volcano has had more frequent historic activity, erupting magmas that are generally more mafic, lower in large ion lithophile elements and higher in Na2O/K2O than magmas erupted from its landward counterpart. Each paired volcano site lies in close proximity to a rhyolitic caldera, situated north or northeast of the volcano pair. However, rare earth element data at the Tolimán‐Atitlán volcano pair imply that mixing between caldera rhyolite and the mafic magma of the paired volcanoes does not occur. Petrographie, isotopic, and other geochemical data from the Tolimán‐Atitlán volcano pair suggest that separate but contemporaneous magma bodies beneath each volcano evolve and pass through the crust at different rates. Atitlán magmas are processed through the crust more efficiently and with greater frequency than Tollman magmas, which undergo longer periods of stagnation interrupted by mafic injection and rapid eruption. This relation appears to hold at the other paired volcano sites and is further evidence that closely spaced volcanoes, with similar subcrustal magma sources, evolve over separate magmatic plumbing systems that traverse the crust. The pairing pattern probably reflects the regional southward migration of the volcanic front.

A tale of two magmas, Fuego, Guatemala

“…Chesner and Rose 1984;Halsor and Rose 1988). Halsor and Rose (1988) studied volcano pairing in Central America, including Fuego-Acatenango.…”

“…Chesner and Rose 1984;Halsor and Rose 1988). Halsor and Rose (1988) studied volcano pairing in Central America, including Fuego-Acatenango. These closely spaced pairs typically have an older landwards volcano, which has erupted more evolved magma, richer in K and LILE than their younger seawards counterpart.…”

Volcanism and geochemistry in Central America: Progress and problems

“…Geochemistry has not proven helpful in defining dividing lines between nearby centers because the geochemical variation within a center is commonly as great as that between adjacent centers. For example, in northern Central America there is strong cross-arc chemical zonation among vents in the same center [Halsor and Rose, 1988]. The volcanoes nearest to the trench have more mafic character and generally lower LIL element contents and higher Ba/La.…”

“…In northern Central America, Halsor and Rose [1988] pointed out several examples of paired volcanoes or short, cross-arc volcanic lineaments (e.g. Santa María -Cerro Quemado, Atitlán -Tolimán, Fuego-Acatenango, and Izalco-Santa Ana).…”

Edifice collapse and related hazards in Guatemala

“…Four sets of paired volcanoes exist in Guatemala (Table 2), and Halsor and Rose (1988) note that the younger of each set is invariably to the south toward the subduction zone. The flank of an older volcano like Acatenango could have an internal plane of weakness for a younger overlapping volcano like Fuego (Fig.…”