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
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 obse...
| Authors: | , , , |
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| Format: | article |
| Status: | Published version |
| Publication Date: | 2001 |
| Country: | México |
| Institution: | Universidad Nacional Autónoma de México |
| Repository: | Redalyc-UNAM |
| OAI Identifier: | oai:redalyc.org:56840402 |
| Online Access: | https://www.redalyc.org/articulo.oa?id=56840402 |
| Access Level: | Open access |
| Keyword: | Ciencias de la Tierra Mexico Ar dating tectonics geochemistry Jalisco block |
| Summary: | 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. |
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