Time constraints on the tectonic evolution of the eastern Sierras Pampeanas (Central Argentina).

Siegfried Siegesmund; A Steenken; R D Martino; K Wemmer; M G Lopez de Luchi; Robert Frei; S Presnyakov; A Guereschi

doi:10.1007/s00531-009-0471-z

Time constraints on the tectonic evolution of the eastern Sierras Pampeanas (Central Argentina).

Siegfried Siegesmund, A Steenken, R D Martino, K Wemmer, M G Lopez de Luchi, Robert Frei, S Presnyakov, A Guereschi

Geology

70 Citations (Scopus)

Abstract

The application of the SHRIMP U/Pb dating technique to zircon and monazite of different rock types of the Sierras de Córdoba provides an important insight into the metamorphic history of the basement domains. Additional constraints on the Pampean metamorphic episode were gained by Pb/Pb stepwise leaching (PbSL) experiments on two titanite and garnet separates. Results indicate that the metamorphic history recorded by Crd-free gneisses (M2) started in the latest Neoproterozoic/earliest Cambrian (553 and 543 Ma) followed by the M4 metamorphism at ~530 Ma that is documented in the diatexites. Zircon ages of 492 Ma in the San Carlos Massif correlate partly with rather low Th/U ratios (<0.1) suggesting their growth by metamorphic fluids. This age is even younger than the PbSL titanite ages of 506 Ma. It is suggested that the fluid alteration relates to the beginning of the Famatinien metamorphic cycle in the neighbouring Sierra de San Luis and has not affected the titanite ages. The PTt evolution can be correlated with the plate tectonic processes responsible for the formation of the Pampean orogene, i.e., the accretion of the Pampean basement to the Río de La Plata craton (M2) and the later collision of the Western Pampean basement with the Pampean basement.

Original language	English
Journal	International Journal of Earth Sciences
Volume	99
Issue number	6
Pages (from-to)	1199-1226
ISSN	1437-3254
DOIs	https://doi.org/10.1007/s00531-009-0471-z
Publication status	Published - 2010

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@article{ca563a50ac3f11df928f000ea68e967b,

title = "Time constraints on the tectonic evolution of the eastern Sierras Pampeanas (Central Argentina).",

abstract = "The application of the SHRIMP U/Pb dating technique to zircon and monazite of different rock types of the Sierras de C{\'o}rdoba provides an important insight into the metamorphic history of the basement domains. Additional constraints on the Pampean metamorphic episode were gained by Pb/Pb stepwise leaching (PbSL) experiments on two titanite and garnet separates. Results indicate that the metamorphic history recorded by Crd-free gneisses (M2) started in the latest Neoproterozoic/earliest Cambrian (553 and 543 Ma) followed by the M4 metamorphism at ~530 Ma that is documented in the diatexites. Zircon ages of 492 Ma in the San Carlos Massif correlate partly with rather low Th/U ratios (<0.1) suggesting their growth by metamorphic fluids. This age is even younger than the PbSL titanite ages of 506 Ma. It is suggested that the fluid alteration relates to the beginning of the Famatinien metamorphic cycle in the neighbouring Sierra de San Luis and has not affected the titanite ages. The PTt evolution can be correlated with the plate tectonic processes responsible for the formation of the Pampean orogene, i.e., the accretion of the Pampean basement to the R{\'i}o de La Plata craton (M2) and the later collision of the Western Pampean basement with the Pampean basement. ",

author = "Siegfried Siegesmund and A Steenken and Martino, {R D} and K Wemmer and {Lopez de Luchi}, {M G} and Robert Frei and S Presnyakov and A Guereschi",

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doi = "10.1007/s00531-009-0471-z",

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T1 - Time constraints on the tectonic evolution of the eastern Sierras Pampeanas (Central Argentina).

AU - Siegesmund, Siegfried

AU - Steenken, A

AU - Martino, R D

AU - Wemmer, K

AU - Lopez de Luchi, M G

AU - Frei, Robert

AU - Presnyakov, S

AU - Guereschi, A

PY - 2010

Y1 - 2010

N2 - The application of the SHRIMP U/Pb dating technique to zircon and monazite of different rock types of the Sierras de Córdoba provides an important insight into the metamorphic history of the basement domains. Additional constraints on the Pampean metamorphic episode were gained by Pb/Pb stepwise leaching (PbSL) experiments on two titanite and garnet separates. Results indicate that the metamorphic history recorded by Crd-free gneisses (M2) started in the latest Neoproterozoic/earliest Cambrian (553 and 543 Ma) followed by the M4 metamorphism at ~530 Ma that is documented in the diatexites. Zircon ages of 492 Ma in the San Carlos Massif correlate partly with rather low Th/U ratios (<0.1) suggesting their growth by metamorphic fluids. This age is even younger than the PbSL titanite ages of 506 Ma. It is suggested that the fluid alteration relates to the beginning of the Famatinien metamorphic cycle in the neighbouring Sierra de San Luis and has not affected the titanite ages. The PTt evolution can be correlated with the plate tectonic processes responsible for the formation of the Pampean orogene, i.e., the accretion of the Pampean basement to the Río de La Plata craton (M2) and the later collision of the Western Pampean basement with the Pampean basement.

AB - The application of the SHRIMP U/Pb dating technique to zircon and monazite of different rock types of the Sierras de Córdoba provides an important insight into the metamorphic history of the basement domains. Additional constraints on the Pampean metamorphic episode were gained by Pb/Pb stepwise leaching (PbSL) experiments on two titanite and garnet separates. Results indicate that the metamorphic history recorded by Crd-free gneisses (M2) started in the latest Neoproterozoic/earliest Cambrian (553 and 543 Ma) followed by the M4 metamorphism at ~530 Ma that is documented in the diatexites. Zircon ages of 492 Ma in the San Carlos Massif correlate partly with rather low Th/U ratios (<0.1) suggesting their growth by metamorphic fluids. This age is even younger than the PbSL titanite ages of 506 Ma. It is suggested that the fluid alteration relates to the beginning of the Famatinien metamorphic cycle in the neighbouring Sierra de San Luis and has not affected the titanite ages. The PTt evolution can be correlated with the plate tectonic processes responsible for the formation of the Pampean orogene, i.e., the accretion of the Pampean basement to the Río de La Plata craton (M2) and the later collision of the Western Pampean basement with the Pampean basement.

U2 - 10.1007/s00531-009-0471-z

DO - 10.1007/s00531-009-0471-z

M3 - Journal article

SN - 1437-3254

VL - 99

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JO - International Journal of Earth Sciences

JF - International Journal of Earth Sciences

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