Paleomagnetic study of El Metate shield volcano (Michoacan, Mexico) confirms its monogenetic nature and young age (similar to 1250 CE)
Por:
Mahgoub, Ahmed Nasser, Bohnel, Harald, Siebe, Claus, Chevrel, Magdalena Oryaelle
Publicada:
15 abr 2017
Resumen:
In a recent study, Chevrel et al. (2016a, b) radiocarbon-dated the
oldest lava flow of the voluminous (similar to 9.2 km(3)) El Metate
shield volcano (Michoacan, Mexico) at cal 1250-1260 CE and proposed that
its eruption was monogenetic in origin, with twelve younger lava flows
emplaced during a short period of only similar to 35 years, but
certainly <275 years. In order to test this hypothesis, we undertook a
detailed paleomagnetic study of five lava flows from El Metate to check
the consistency of their paleomagnetic directions. Additionally, a group
of representative specimens was treated with the double-heating Thellier
experiment using the IZZI protocol for paleointensity determination.
Flow mean paleomagnetic directions obtained for four of the flows are
indistinguishable, and discordant directions were obtained from the site
of the 5th flow measured, probably due to the tilting of the sampled
block after remanence acquisition. Mean paleodirections and intensities
were used for paleomagnetic dating applying the global paleosecular
variation model SHA.DIF.14k. The resulting age range for the eruption is
11501290 CE, which overlaps with the range previously determined by the
C-14 method by Chevrel et al. (2016a). Accepting the C-14 age of the
oldest flow as the maximum age, the age range would be reduced to
1250-1290 CE, which strongly supports the hypothesis of a monogenetic
nature of the El Metate eruption. (C) 2017 Elsevier B.V. All rights
reserved.
Filiaciones:
Mahgoub, Ahmed Nasser:
Univ Nacl Autonoma Mexico, Ctr Geociencias, Blvd Juriquilla 3001, Queretaro 76230, Mexico
Bohnel, Harald:
Univ Nacl Autonoma Mexico, Ctr Geociencias, Blvd Juriquilla 3001, Queretaro 76230, Mexico
Siebe, Claus:
Univ Nacl Autonoma Mexico, Inst Geofis, Dept Vulcanol, Ciudad De Mexico 04510, Mexico
Chevrel, Magdalena Oryaelle:
Univ Blaise Pascal, CNRS, Lab Magmas & Volcans, 6 Av Blaise Pascal, F-63178 Aubiere, France
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