Transfer of the Argentine Precordillera terrane from Laurentia: Constraints from detrital zircon geochronology.

Thomas, W., Astini. R., Mueller, P., Gehrels, G., and Wooden, J., 2004, Geology, v. 32, p. 965-968.

Abstract

Age spectra from U/Pb and ²⁰⁷Pb/²⁰⁶Pb analyses of detrital zircons from synrift sandstone in the Lower Cambrian Cerro Totora Formation of the Argentine Precordillera have strong similarities to those from late synrift sandstones in the Lower Cambrian Rome Formation of southern Laurentia (Alabama).  Ages from the Cerro Totora sample cluster at 970-1160 Ma (60% of analyzed zircons), 1300-1490 (24%), and 1640-1890 (16%) Ma.  Similarly, ages of detrital zircons from two Rome samples cluster at 970-1240 Ma (32% of analyzed zircons), 1270-1540 (31%), 1610-1840 (14%), 1890-1970 (5%), and 2310-2930 (18%) Ma.  The ages of detrital zircons from Rome and Cerro Totora sandstones are consistent with sediment supply from the Grenville province and Laurentian mid-continent provinces such as Granite-Rhyolite and Trans-Hudson.  The older cluster in the Rome sandstones corresponds in age to the Laurentian Superior province.  Neither the Rome nor Cerro Totora samples include components younger than Grenville, and the lack of zircons from distinctly Gondwanan-age provinces is consistent with a Laurentian provenance.  The detrital-zircon ages support previous interpretations that the Precordillera was rifted from the Ouachita embayment of Laurentia during Early Cambrian time.

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