Zircon xenocryst resorption and magmatic regrowth at El Chichón Volcano, Chiapas, Mexico

Brenda Pack, Axel K. Schmitt, Julie Roberge, Felipe Garcia Tenorio, Brian N. Damiata

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

© 2016 Elsevier B.V. El Chichón volcano is the only active volcano located within the Chiapanecan Volcanic Arc in southern Mexico, which lies between the Trans-Mexican Volcanic Belt and the Central American Volcanic Arc. Previous studies have shown that ~12 eruptions have occurred at El Chichón within the last 8000 years, forming a complex of lava domes with a central crater and surrounding pyroclastic deposits. Here, we report the discovery of zircon in Holocene El Chichón rocks, which were analyzed by high spatial resolution imaging (color cathodoluminescence CCL) and isotopic (secondary ionization mass spectrometry SIMS) methods to resolve core and rim crystallization ages. Pumice samples from five proximal pyroclastic flow and fall-out deposits were collected based on published stratigraphy. Two of the samples were further (re-)classified by new 14C dates. In addition, we sampled two lavas from the 1982 eruption and from remnants of the older Somma lava complex. Zircon crystals were dated using 230Th/238U disequilibrium (U-Th) and U-Pb geochronology. U-Th zircon ages fall between near eruption ages and ca. 84 ka, with overlapping ages in all samples. By contrast, zircon core U-Pb ages range between ca. 290 Ma and 1.9 Ga. These ages are consistent with xenocrystic origins and their heterogeneity indicates derivation from clastic country rocks. Strong age contrasts between inherited xenocrystic and young magmatic domains in individual zircon crystals are evidence for arrested assimilation of crustal rocks where initially zircon-undersaturated magmas cooled rapidly to form a crystal mush or subsolidus amalgamate as a crustally contaminated boundary layer. This layer contributed zircon crystals to eruptible magma during episodic recharge events followed by partial melt extraction, mixing and homogenization. Zircon overgrowths are significantly older than major minerals whose U-series ages and sharp zonation boundaries suggest crystallization only within a few ka before eruption. This implies that zircon can detect magmatic longevity which is obscured in the major mineral record.
Original languageAmerican English
Pages (from-to)170-182
Number of pages13
JournalJournal of Volcanology and Geothermal Research
DOIs
StatePublished - 1 Feb 2016

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Volcanoes
resorption
Mexico
regrowth
volcanoes
volcanic eruptions
zircon
volcano
volcanology
rocks
lava
crystals
arcs
deposits
minerals
crystallization
volcanic eruption
pumice
geochronology
crystal

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Pack, Brenda ; Schmitt, Axel K. ; Roberge, Julie ; Tenorio, Felipe Garcia ; Damiata, Brian N. / Zircon xenocryst resorption and magmatic regrowth at El Chichón Volcano, Chiapas, Mexico. In: Journal of Volcanology and Geothermal Research. 2016 ; pp. 170-182.
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abstract = "{\circledC} 2016 Elsevier B.V. El Chich{\'o}n volcano is the only active volcano located within the Chiapanecan Volcanic Arc in southern Mexico, which lies between the Trans-Mexican Volcanic Belt and the Central American Volcanic Arc. Previous studies have shown that ~12 eruptions have occurred at El Chich{\'o}n within the last 8000 years, forming a complex of lava domes with a central crater and surrounding pyroclastic deposits. Here, we report the discovery of zircon in Holocene El Chich{\'o}n rocks, which were analyzed by high spatial resolution imaging (color cathodoluminescence CCL) and isotopic (secondary ionization mass spectrometry SIMS) methods to resolve core and rim crystallization ages. Pumice samples from five proximal pyroclastic flow and fall-out deposits were collected based on published stratigraphy. Two of the samples were further (re-)classified by new 14C dates. In addition, we sampled two lavas from the 1982 eruption and from remnants of the older Somma lava complex. Zircon crystals were dated using 230Th/238U disequilibrium (U-Th) and U-Pb geochronology. U-Th zircon ages fall between near eruption ages and ca. 84 ka, with overlapping ages in all samples. By contrast, zircon core U-Pb ages range between ca. 290 Ma and 1.9 Ga. These ages are consistent with xenocrystic origins and their heterogeneity indicates derivation from clastic country rocks. Strong age contrasts between inherited xenocrystic and young magmatic domains in individual zircon crystals are evidence for arrested assimilation of crustal rocks where initially zircon-undersaturated magmas cooled rapidly to form a crystal mush or subsolidus amalgamate as a crustally contaminated boundary layer. This layer contributed zircon crystals to eruptible magma during episodic recharge events followed by partial melt extraction, mixing and homogenization. Zircon overgrowths are significantly older than major minerals whose U-series ages and sharp zonation boundaries suggest crystallization only within a few ka before eruption. This implies that zircon can detect magmatic longevity which is obscured in the major mineral record.",
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Zircon xenocryst resorption and magmatic regrowth at El Chichón Volcano, Chiapas, Mexico. / Pack, Brenda; Schmitt, Axel K.; Roberge, Julie; Tenorio, Felipe Garcia; Damiata, Brian N.

In: Journal of Volcanology and Geothermal Research, 01.02.2016, p. 170-182.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Zircon xenocryst resorption and magmatic regrowth at El Chichón Volcano, Chiapas, Mexico

AU - Pack, Brenda

AU - Schmitt, Axel K.

AU - Roberge, Julie

AU - Tenorio, Felipe Garcia

AU - Damiata, Brian N.

PY - 2016/2/1

Y1 - 2016/2/1

N2 - © 2016 Elsevier B.V. El Chichón volcano is the only active volcano located within the Chiapanecan Volcanic Arc in southern Mexico, which lies between the Trans-Mexican Volcanic Belt and the Central American Volcanic Arc. Previous studies have shown that ~12 eruptions have occurred at El Chichón within the last 8000 years, forming a complex of lava domes with a central crater and surrounding pyroclastic deposits. Here, we report the discovery of zircon in Holocene El Chichón rocks, which were analyzed by high spatial resolution imaging (color cathodoluminescence CCL) and isotopic (secondary ionization mass spectrometry SIMS) methods to resolve core and rim crystallization ages. Pumice samples from five proximal pyroclastic flow and fall-out deposits were collected based on published stratigraphy. Two of the samples were further (re-)classified by new 14C dates. In addition, we sampled two lavas from the 1982 eruption and from remnants of the older Somma lava complex. Zircon crystals were dated using 230Th/238U disequilibrium (U-Th) and U-Pb geochronology. U-Th zircon ages fall between near eruption ages and ca. 84 ka, with overlapping ages in all samples. By contrast, zircon core U-Pb ages range between ca. 290 Ma and 1.9 Ga. These ages are consistent with xenocrystic origins and their heterogeneity indicates derivation from clastic country rocks. Strong age contrasts between inherited xenocrystic and young magmatic domains in individual zircon crystals are evidence for arrested assimilation of crustal rocks where initially zircon-undersaturated magmas cooled rapidly to form a crystal mush or subsolidus amalgamate as a crustally contaminated boundary layer. This layer contributed zircon crystals to eruptible magma during episodic recharge events followed by partial melt extraction, mixing and homogenization. Zircon overgrowths are significantly older than major minerals whose U-series ages and sharp zonation boundaries suggest crystallization only within a few ka before eruption. This implies that zircon can detect magmatic longevity which is obscured in the major mineral record.

AB - © 2016 Elsevier B.V. El Chichón volcano is the only active volcano located within the Chiapanecan Volcanic Arc in southern Mexico, which lies between the Trans-Mexican Volcanic Belt and the Central American Volcanic Arc. Previous studies have shown that ~12 eruptions have occurred at El Chichón within the last 8000 years, forming a complex of lava domes with a central crater and surrounding pyroclastic deposits. Here, we report the discovery of zircon in Holocene El Chichón rocks, which were analyzed by high spatial resolution imaging (color cathodoluminescence CCL) and isotopic (secondary ionization mass spectrometry SIMS) methods to resolve core and rim crystallization ages. Pumice samples from five proximal pyroclastic flow and fall-out deposits were collected based on published stratigraphy. Two of the samples were further (re-)classified by new 14C dates. In addition, we sampled two lavas from the 1982 eruption and from remnants of the older Somma lava complex. Zircon crystals were dated using 230Th/238U disequilibrium (U-Th) and U-Pb geochronology. U-Th zircon ages fall between near eruption ages and ca. 84 ka, with overlapping ages in all samples. By contrast, zircon core U-Pb ages range between ca. 290 Ma and 1.9 Ga. These ages are consistent with xenocrystic origins and their heterogeneity indicates derivation from clastic country rocks. Strong age contrasts between inherited xenocrystic and young magmatic domains in individual zircon crystals are evidence for arrested assimilation of crustal rocks where initially zircon-undersaturated magmas cooled rapidly to form a crystal mush or subsolidus amalgamate as a crustally contaminated boundary layer. This layer contributed zircon crystals to eruptible magma during episodic recharge events followed by partial melt extraction, mixing and homogenization. Zircon overgrowths are significantly older than major minerals whose U-series ages and sharp zonation boundaries suggest crystallization only within a few ka before eruption. This implies that zircon can detect magmatic longevity which is obscured in the major mineral record.

U2 - 10.1016/j.jvolgeores.2016.01.011

DO - 10.1016/j.jvolgeores.2016.01.011

M3 - Article

SP - 170

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JO - Journal of Volcanology and Geothermal Research

JF - Journal of Volcanology and Geothermal Research

SN - 0377-0273

ER -