Reconstruction of the volcanic history of the Tacámbaro-Puruarán area (Michoacán, México) reveals high frequency of Holocene monogenetic eruptions

Abstract

The 690 km 2 Tacámbaro-Puruarán area located at the arc-front part of the Michoácan-Guanajuato volcanic field in the Trans-Mexican Volcanic Belt (TMVB) records a protracted history of volcanism that culminated with intense monogenetic activity in the Holocene. Geologic mapping, 40 Ar/ 39 Ar and 14 C radiometric dating, and whole-rock chemical analyses of volcanic products provide insights to that history. Eocene volcanics (55-40 Ma) exposed at uplifted blocks are related to a magmatic arc that preceded the TMVB. Early TMVB products are represented by poorly exposed Pliocene silicic domes (5-2 Ma). Quaternary (<2 Ma) volcanoes (114 mapped) are mainly scoria cones with lavas (49 vol.%), viscous lava flows (22 vol.%), and lava shields (22 vol.%). Erupted products are dominantly either basaltic andesites (37 vol. %), or andesites (17 vol.%), or span across both compositions (28 vol.%). Basalts (9 vol.%), dacites (4 vol.%), shoshonites (2 vol.%), and other alkali-rich rocks (<3 vol.%) occur subordinately. Early-Pleistocene volcanism was bimodal (dacites and basalts) and voluminous while since 1 Ma smallvolume eruptions of intermediate magmas have dominated.Higher rates of lithospheric extension in the Quaternary may have allowed a larger number of small, poorly evolved dikes to reach the surface during this period. Eruptive centers as old as 1.7 Ma are aligned in a NE direction parallel to both, basement faults and the direction of regional compressive stress, implying structural control on volcanic activity. Data suggest that volcanism was strongly pulsatory and fed by localized lowdegree partial melting of mantle sources. In the Holocene, at least 13 eruptions occurred (average recurrence interval of 800 years). These produced~3.8 km 3 of basaltic andesitic to andesitic magma and included four eruptions dated at~1,000; 4,000; 8,000; and 11,000 years BC (calibrated 14 C ages). To date, this is one of the highest monogenetic eruption frequencies detected within such a small area in a subduction-related arc-setting. These anomalous rates of monogenetic activity in an area with thick crust (>30 km) may be related to high rates of magma production at depth and a favorable tectonic setting.

Rift zones and magma plumbing system of Piton de la Fournaise volcano: How do they differ from Hawaii and Etna?

“…In the first procedure, we directly determined the volume CV of 231 cones by subtracting the topography located below a certain level taken as the base of the edifices, following the same procedure as Guilbaud et al (2012). This dataset made of the cone footprint A co and CV shows a clear power-law relationship between the planar surface and the volume of each cone over 3 and 5 orders of magnitude for A co and CV, respectively (Fig.…”

“…Bulk volume estimates for recent lava flows Gérente, 1977a, 1977b;Bachèlery et al, 1982;Lénat et al, 1989;Roult et al, 2012) were correlated to the cone's volumes determined from the DEM, following the methodology described above. The correlation was further constrained for the largest cone volumes encountered at Piton de la Fournaise by data of Etna (Wadge, 1977;Neri et al, 2011), the Auckland volcanic province (Kereszturi et al, 2013b), and the Michoácan-Guanajuato volcanic field (Guilbaud et al, 2012). The overall dataset ( Fig.…”

Basic limnology of 30 continental waterbodies of the Transmexican Volcanic Belt across climatic and environmental gradients

“…Subsaline and hyposaline waterbodies had also low [Ca 2+ ] proportions ( Figure 3) ] (Santa Rosa, Tacám-baro, Quechulac); however, those with the lowest TDS (< 100 mg/l) were mostly [Ca 2+ ] dominated. This ionic dominance pattern suggest that the lowest TDS lakes represent the least evolved waters (Hardie and Eugster, 1970;Kilham, 1990), with ionic dominance determined mostly by weather-DISCUSSION ing processes of the basaltic andesite rocks that dominate in the TMVB (Guilbaud et al, 2012), while the ionic composition of subsaline and hyposaline lakes is mostly controlled by evaporative concentration and carbonate precipitation (Eugster and Hardie, 1978;Kilham, 1990) …”

The erupted volumes of tephra from maar volcanoes and estimates of their VEI magnitude: Examples from the late Cenozoic Newer Volcanics Province, south-eastern Australia

“…This is because it is difficult to determine the origin of preserved distal deposits because of so many closely-spaced volcanic centres in the Newer Volcanics Province. The volume of ash produced by a scoria cone for example, can be up to 8 times the volume of the cone in violent Strombolian and micro-Plinian eruptions (Guilbaud et al 2012), so our volume estimates are therefore conservative, and represent minimum values for these eruptive centres.…”