Nd isotopic ages of crust formation and metamorphism in the Precambrian of eastern and southern Mexico

P. Jonathan Patchett, Joaquin Ruiz

Research output: Contribution to journalArticle

209 Citations (Scopus)

Abstract

Sm-Nd ages for garnets in the three Precambrian exposures of eastern and southern Mexico demonstrate that they belong to the Grenville tectonothermal event. The Sm-Nd garnet ages of 0.95 Ga for the Oaxacan Complex and 0.90 Ga for the Huiznopala Gneiss, Molango and the Novillo Gneiss, Ciudad Victoria, are postdated 75 Ma by Rb-Sr ages on biotites. Both sets of data document a cooling history following Grenville metamorphism at or before 1.0 Ga ago. Our garnet data are consistent with a blocking temperature for Sm-Nd in that mineral around 600° C suggested by Humphries and Cliff (1982). The three Precambrian occurrences have Nd chemical ages of separation from depleted mantle (TDM) grouped in the range 1.40-1.60 Ga. This may result from derivation of the rocks from actual crustal protoliths which had been separated from the mantle 0.5 Ga before the Grenville Orogeny. It is much more likely, however, that crustal materials of 1.7 Ga or older age were mixed with mantle-derived products during Grenville events to produce intermediate TDM ages and e{open}Nd values around zero 1.0 Ga ago.

Original languageEnglish (US)
Pages (from-to)523-528
Number of pages6
JournalContributions to Mineralogy and Petrology
Volume96
Issue number4
DOIs
StatePublished - Dec 1987

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Garnets
Mexico
garnets
Precambrian
crusts
gneiss
Earth mantle
Time division multiplexing
metamorphism
crust
cliffs
garnet
mantle
Minerals
derivation
Rocks
minerals
histories
occurrences
rocks

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences(all)
  • Environmental Science(all)

Cite this

Nd isotopic ages of crust formation and metamorphism in the Precambrian of eastern and southern Mexico. / Patchett, P. Jonathan; Ruiz, Joaquin.

In: Contributions to Mineralogy and Petrology, Vol. 96, No. 4, 12.1987, p. 523-528.

Research output: Contribution to journalArticle

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