TY - JOUR
T1 - Siliciclastic Ordovician to Silurian units of the Argentine Precordillera
T2 - Constraints on provenance and tectonic setting in the proto-Andean margin of Gondwana
AU - Abre, P.
AU - Cingolani, C. A.
AU - Cairncross, B.
AU - Chemale, F.
PY - 2012/12
Y1 - 2012/12
N2 - A combination of petrography, geochemistry, Sm-Nd, Pb-Pb and U-Pb detrital zircon dating provide constraints to the provenance of Middle Ordovician to Early Silurian clastic sequences of the Precordillera s.s. as a part of the Cuyania terrane in western-central Argentina. The uniformity shown by the provenance proxies indicate that there were no important changes in the provenance within these units. A dominant upper crustal component is evident as well as a subordinate mafic input. Nd isotopes indicate εNd of -5.4, f{hook}Sm/Nd -0.34 and TDM 1.57 Ga in average for all the units studied. Pb-isotope ratios display average values for 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb of 19.37, 15.86 and 39.43 respectively. Detrital zircon dating further constraints the input as being dominantly of Mesoproterozoic age (51-83%), but with contributions from Neoproterozoic-Lower Cambrian (9-31%), Middle Cambrian to Ordovician grains (recorded up to 7%), and Palaeoproterozoic (2-7%) sources. The combination of the different provenance approaches applied indicates that the Mesoproterozoic Cuyania terrane basement, and partially the Pampia terrane were the main sources. The new information provided for the Ordovician to Silurian clastic sequences permitted enhanced the known geochemical and isotopic dataset to constrain the tectonic evolution of the Cuyania terrane. The interpretation of the obtained data supports that the terrane accretion to the proto-Andean margin of Gondwana probably occurred during Middle to early Upper Ordovician.
AB - A combination of petrography, geochemistry, Sm-Nd, Pb-Pb and U-Pb detrital zircon dating provide constraints to the provenance of Middle Ordovician to Early Silurian clastic sequences of the Precordillera s.s. as a part of the Cuyania terrane in western-central Argentina. The uniformity shown by the provenance proxies indicate that there were no important changes in the provenance within these units. A dominant upper crustal component is evident as well as a subordinate mafic input. Nd isotopes indicate εNd of -5.4, f{hook}Sm/Nd -0.34 and TDM 1.57 Ga in average for all the units studied. Pb-isotope ratios display average values for 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb of 19.37, 15.86 and 39.43 respectively. Detrital zircon dating further constraints the input as being dominantly of Mesoproterozoic age (51-83%), but with contributions from Neoproterozoic-Lower Cambrian (9-31%), Middle Cambrian to Ordovician grains (recorded up to 7%), and Palaeoproterozoic (2-7%) sources. The combination of the different provenance approaches applied indicates that the Mesoproterozoic Cuyania terrane basement, and partially the Pampia terrane were the main sources. The new information provided for the Ordovician to Silurian clastic sequences permitted enhanced the known geochemical and isotopic dataset to constrain the tectonic evolution of the Cuyania terrane. The interpretation of the obtained data supports that the terrane accretion to the proto-Andean margin of Gondwana probably occurred during Middle to early Upper Ordovician.
KW - Cuyania terrane
KW - Geochemistry
KW - Ordovician-Silurian
KW - Provenance
KW - U-Pb detrital zircon dating
KW - Western Gondwana
UR - http://www.scopus.com/inward/record.url?scp=84867897709&partnerID=8YFLogxK
U2 - 10.1016/j.jsames.2012.07.013
DO - 10.1016/j.jsames.2012.07.013
M3 - Article
AN - SCOPUS:84867897709
SN - 0895-9811
VL - 40
SP - 1
EP - 22
JO - Journal of South American Earth Sciences
JF - Journal of South American Earth Sciences
ER -
