K-Ar ages of four mafic lavas from the Central Jalisco Volcanic Lineament: Supporting evidence for a NW migration of volcanism within the Jalisco block, western Mexico

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Autor principal: William L. Bandy
Formato: Artículo científico
Lenguaje:en
Publicado: Universidad Nacional Autónoma de México 2001
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author William L. Bandy
author_facet William L. Bandy
contents K-Ar ages of four mafic lavas from the Central Jalisco Volcanic Lineament: Supporting evidence for a NW migration of volcanism within the Jalisco block, western Mexico William L. Bandy Fred W. McDowell Jaime Urrutia Fucugauchi Ofelia Morton Bermea Ciencias de la Tierra Mexico Ar dating tectonics geochemistry Jalisco block Four of 14 Plio-Quaternary mafic rock samples collected along the Central Jalisco Volcanic Lineament (CJVL) were datedby the K-Ar method to verify the existence of a systematic decrease in the age of volcanism northwestward along the lineament,as suggested by previous geological and geophysical observations. The results are in agreement with the proposed age progression.Specifically, these results support the contention that the volcanism along the southeastern most segment of the CJVL (locatedbetween the Ayutla and Atenguillo volcanic fields) occurred at about 3.0 Ma, volcanism along the segment to the NW (between theAtenguillo and Mascota grabens) at 1.8 to 1.9 Ma, and from 0.5 to 0.06 Ma within the Mascota graben. The lack of observedvolcanism along the northwestern most segment of the lineament (between the Mascota graben and San Sebastián) is also consistentwith the proposed age progression. A geochemical analysis was performed on all 14 samples and a rare earth element analysis wasperformed on the four dated samples. These analyses, in conjunction with the results of previous studies, indicate that the volcanismalong the CJVL exhibits a varied composition similar to that exhibited by the Plio-Quaternary volcanic rocks located within themain volcanic fields. Additionally, the outcrop from which the Mascota sample (dated as 0.166 ± 0.038 Ma) was obtained is cutby a northwest oriented strike-slip fault (tentatively identified from striation roughness to be right-lateral) indicating that recentstrike-slip deformation has occurred in the Mascota graben. 2001 artículo científico 0016-7169 https://www.redalyc.org/articulo.oa?id=56840402 en http://www.redalyc.org/revista.oa?id=568 Geofísica Internacional application/pdf Universidad Nacional Autónoma de México Geofísica Internacional (México) Num.4 Vol.40
format Artículo científico
id redalyc_56840402
institution Redalyc
language en
publishDate 2001
publisher Universidad Nacional Autónoma de México
spellingShingle K-Ar ages of four mafic lavas from the Central Jalisco Volcanic Lineament: Supporting evidence for a NW migration of volcanism within the Jalisco block, western Mexico
William L. Bandy
Ciencias de la Tierra
Mexico
Ar dating
tectonics
geochemistry
Jalisco block
K-Ar ages of four mafic lavas from the Central Jalisco Volcanic Lineament: Supporting evidence for a NW migration of volcanism within the Jalisco block, western Mexico William L. Bandy Fred W. McDowell Jaime Urrutia Fucugauchi Ofelia Morton Bermea Ciencias de la Tierra Mexico Ar dating tectonics geochemistry Jalisco block Four of 14 Plio-Quaternary mafic rock samples collected along the Central Jalisco Volcanic Lineament (CJVL) were datedby the K-Ar method to verify the existence of a systematic decrease in the age of volcanism northwestward along the lineament,as suggested by previous geological and geophysical observations. The results are in agreement with the proposed age progression.Specifically, these results support the contention that the volcanism along the southeastern most segment of the CJVL (locatedbetween the Ayutla and Atenguillo volcanic fields) occurred at about 3.0 Ma, volcanism along the segment to the NW (between theAtenguillo and Mascota grabens) at 1.8 to 1.9 Ma, and from 0.5 to 0.06 Ma within the Mascota graben. The lack of observedvolcanism along the northwestern most segment of the lineament (between the Mascota graben and San Sebastián) is also consistentwith the proposed age progression. A geochemical analysis was performed on all 14 samples and a rare earth element analysis wasperformed on the four dated samples. These analyses, in conjunction with the results of previous studies, indicate that the volcanismalong the CJVL exhibits a varied composition similar to that exhibited by the Plio-Quaternary volcanic rocks located within themain volcanic fields. Additionally, the outcrop from which the Mascota sample (dated as 0.166 ± 0.038 Ma) was obtained is cutby a northwest oriented strike-slip fault (tentatively identified from striation roughness to be right-lateral) indicating that recentstrike-slip deformation has occurred in the Mascota graben. 2001 artículo científico 0016-7169 https://www.redalyc.org/articulo.oa?id=56840402 en http://www.redalyc.org/revista.oa?id=568 Geofísica Internacional application/pdf Universidad Nacional Autónoma de México Geofísica Internacional (México) Num.4 Vol.40
title K-Ar ages of four mafic lavas from the Central Jalisco Volcanic Lineament: Supporting evidence for a NW migration of volcanism within the Jalisco block, western Mexico
topic Ciencias de la Tierra
Mexico
Ar dating
tectonics
geochemistry
Jalisco block
url https://www.redalyc.org/articulo.oa?id=56840402