Implications of reworking processes on tephra distribution during volcanic eruptions: The case of Parícutin (1943–1952, western Mexico)

Abstract

Parícutin in western Mexico is considered one of the most studied monogenetic volcanoes worldwide. The volcano began its formation in the middle of a cornfield in February 1943 and lasted until March 1952. Descriptions of the eruption documented the remobilization of unconsolidated primary ashfall by rainfall and wind in minor proportions. Despite these descriptions, the resulting reworked deposits have not yet been described in stratigraphic sequence. We present the first stratigraphic study of interfingered primary pyroclastic and reworked deposits of Parícutin's succession. We identify 13 units, of which seven correspond to reworked deposits dispersed around the volcano. These deposits display sedimentary structures produced by tephra remobilization due to lahars and stream flows. In addition, some layers display dunes and ripples generated by dust storms. By using GIS tools, we integrated the existing data with our new composite stratigraphic column, the distribution map of the syn-eruptive reworked deposits and a new isopach map. This new evaluation reveals that more than 70% of the total thicknesses around the volcano correspond to syn-eruptive reworked deposits (R1-R4 units). Therefore, previous studies had overestimated the distribution of primary tephra from the Parícutin explosive phases.The lowest and flattest areas with wide rill networks, which are located 4-6 km north of the volcano, are composed of up to 90% reworked deposits. In contrast, proximal locations with gentler slopes located at medium altitudes better preserve pyroclastic deposits. This study brings new light to understanding the sedimentary processes that occur during volcanic eruptions and highlights the importance of recognizing pyroclastic and reworked deposits during monogenetic eruptions.

The recent volcanism of Flores Island (Azores): Stratigraphy and eruptive history of Funda Volcanic System

“…It is therefore reasonable to consider that a significant, but unknown, portion of pyroclastic material is deposited offshore, as commonly reported for other explosive eruptions on small islands (e.g., Andronico and Pistolesi, 2010;Pimentel et al, 2015Pimentel et al, , 2021Kueppers et al, 2019). In the case of Flores, and as it happens in tropical and subtropical climates with strong winds and/or intense rainfall regimes, this is aggravated by the high syn-and postdepositional reworking of subaerial exposures (Bolós et al, 2021), and thus the estimates presented here must be considered as minimum erupted volumes. The resulting 0.039 km 3 total volume of FVS2 eruption corresponds to an event with a volcanic explosivity index of 3 (VEI; Newhall and Self, 1982).…”

Youngest Iberian Holocene volcanic eruptions and paleoenvironmental evolution of a barrier-paleolake in the Garrotxa Volcanic Field (NE Spain)

“…Eruptions of mostly fine-grained ash usually trigger abrupt and considerable erosion, generating pyroclastic flows and lahars, and causing downstream aggradation (e.g. Bolós et al, 2021; De Rita et al, 1997; Hayes et al, 2002; Manville et al, 2009).…”

Petrogenesis of mafic-intermediate magmatism of the Michoacán–Guanajuato volcanic field in Western Mexico. A geochemical review

“…The MGVF is one of the largest monogenetic volcanic fields on Earth covering ~40,000 km 2 , in the west-central section of the TMVB (Hasenaka and Carmichael, 1985;Valentine and Connor, 2015;Sosa-Ceballos et al, 2021). It contains the youngest continental volcano in Mexico, Paricutin cinder cone (Foshang and González, 1956;Cebriá et al, 2011;Rowe et al, 2011;Larrea et al, 2017;Bolós et al, 2021Bolós et al, , 2021. It consists in more than 1200 vents with a large variety of volcanic structures, such as scoria cones, maar craters, medium-size shield volcanoes, lava domes, and lava flows (Hasenaka and Carmichael 1987;Hasenaka 1994;Guilbaud et al, 2012;Mahgoub et al, 2017;Bolós et al, 2021;Sosa-Ceballos et al, 2021).…”