The similar to AD 500-700 (Late Classic) El Astillero and El Pedregal volcanoes (Michoacan, Mexico): a new monogenetic cluster in the making?
Por:
Larrea, Patricia, Siebe, Claus, Juarez-Arriaga, Erick, Salinas, Sergio, Ibarra, Hector, Bohnel, Harald
Publicada:
1 oct 2019
Categoría:
Geochemistry and petrology
Resumen:
The recent identification of Holocene volcanic clusters in small areas
within the Michoacan Guanajuato Volcanic Field (MGVF) opens several
questions regarding future volcanic hazard assessments in this region.
Documenting vent alignments and eruption recurrence intervals within
clusters will provide parameters necessary for making temporal and
spatial hazard evaluations. Here, we present a possible new case of a
small cluster consisting of only two monogenetic volcanoes, El Astillero
and El Pedregal located in the similar to 4400-km(2) Tancitaro-Nueva
Italia region in the southwestern part of the MGVF, only 25 km to the
south of Paricutin volcano. We determined from paleomagnetic and
radiocarbon dating that El Astillero and El Pedregal most likely erupted
one after the other between AD 500 and 700 (within the Late Classic
period of Mesoamerican archeology). While the eruptions were likely
separated by a short period of time, the exact length is difficult to
ascertain. After the similar to 6 years of total estimated eruption
duration of the two volcanoes, both together occupied an area of 14.7
km(2) and emitted a dense rock equivalent (DRE) volume of magma of
similar to 0.5 km(3). Notable characteristics of the eruptions include a
switch from the explosive activity exclusive of El Astillero
(Strombolian) to effusive activity early after the initiation of the El
Astillero eruption, a shift in the active vents, and a progressive
change in the bulk magma composition from basaltic andesite to andesite
throughout the duration of the eruption. This activity first formed the
El Astillero scoria cone and tephra deposits followed by its lava field
and ended with the emplacement of the El Pedregal viscous lavas. The
discovery of pre-Hispanic pottery sherds and obsidian artifacts
underneath the El Astillero tephra fallout unambiguously attests to
human activities in the area before the eruption. Judging by their
eruptive style, the eruptions probably had a limited impact on the small
area affected and the surrounding human activities, but the hazard for
this area remains since El Astillero and El Pedregal could represent the
initial stages of a new cluster that is still in the making. If so,
another eruption should be expected in this area again.
Filiaciones:
Larrea, Patricia:
Univ Chile, Fac Ciencias Fis & Matemat, Dept Geol, Plaza Ercilla 803, Santiago, Chile
Univ Chile, Fac Ciencias Fis & Matemat, Andean Geothermal Ctr Excellence CEGA, Plaza Ercilla 803, Santiago, Chile
Miami Univ, Dept Geol & Environm Earth Sci, 118 Shideler Hall, Oxford, OH 45056 USA
Univ Nacl Autonoma Mexico, Inst Geofis, Dept Vulcanol, Ciudad Univ, Ciudad De Mexico 04510, Mexico
Siebe, Claus:
Univ Nacl Autonoma Mexico, Inst Geofis, Dept Vulcanol, Ciudad Univ, Ciudad De Mexico 04510, Mexico
Juarez-Arriaga, Erick:
Univ Nacl Autonoma Mexico, Ctr Geociencias, Blvd Juriquilla 3001, Queretaro 76230, Mexico
Salinas, Sergio:
Univ Nacl Autonoma Mexico, Fac Ingn, Div Ingn Ciencias Tierra, Ciudad Univ, Ciudad De Mexico 04510, Mexico
Ibarra, Hector:
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
|