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Southward migration of continental volcanic activity in the Sierra de Las Cruces, Mexico: palaeomagnetic and radiometric evidence

Osete López, María Luisa and Ruiz Martínez, Vicente Carlos and Caballero Miranda, Cecilia and Galindo Francisco, Mª del Carmen and Urrutia Fucugauchi, Jaime and Tarling, Donald H. (2000) Southward migration of continental volcanic activity in the Sierra de Las Cruces, Mexico: palaeomagnetic and radiometric evidence. Tectonophysics, 318 . pp. 201-215. ISSN 0040-1951

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Abstract

New Palaeomagnetic data for 30 sites (271 samples) and K–Ar data from five units in the Sierra de Las Cruces,
western Basin of Mexico, provide constraints on the spatial-temporal evolution of arc magmatism in the central
Trans-Mexican Volcanic Belt. The normal and reversed directions show a polarity pattern with a consistent spatial
zonation perpendicular to the NNW–SSE trend of the range. The magnetostratigraphy and K–Ar dates indicate that
volcanic activity in the Sierra de Las Cruces migrated southeastward at a mean rate of 1.6 cm/a, between 3.6 and
1.8 Ma, and that the rate of migration may have been higher, up to 4 cm/a, during the Gauss Chron. Normal and
reversed directions pass the reversal test at a 95% confidence level. The mean Plio-Quaternary palaeomagnetic
direction for Sierra de Las Cruces is D=350.7°, I=30.6° (N=25, k=30.7, α95=5.3°). The declination deviates to the
west of the expected direction, which suggests that small counterclockwise rotations could take place during formation
of the Sierra de Las Cruces volcanics.


Item Type:Article
Uncontrolled Keywords:Continental volcanism; K–Ar dating; Palaeomagnetism; Trans-Mexican Volcanic Belt; Volcanic activity migration
Subjects:Sciences > Geology > Geochemistry
Sciences > Geology > Geodynamics
ID Code:12041
Deposited On:19 Jan 2011 13:31
Last Modified:19 Jan 2011 13:31

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