Skip to main content
    • Aa
    • Aa

Age and origin of coeval TTG, I- and S-type granites in the Famatinian belt of NW Argentina

  • R. J. Pankhurst (a1), C. W. Rapela (a2) and C. M. Fanning (a3)

Three granitoid types are recognised in the Famatinian magmatic belt of NW Argentina, based on lithology and new geochemical data: (a) a minor trondhjemite–tonalite–granodiorite (TTG) group, (b) a metaluminous I-type gabbro-monzogranite suite, and (c) S-type granites. The latter occur as small cordieritic intrusions associated with 1-type granodiorites and as abundant cordierite-bearing facies in large batholithic masses. Twelve new SHRIMP U-Pb zircon ages establish the contemporaneity of all three types in Early Ordovician times (mainly 470-490 Ma ago). Sr- and Nd-isotopic data suggest that, apart from some TTG plutons of asthenospheric origin, the remaining magmas were derived from a Proterozoic crust-lithospheric mantle section. Trace element modelling suggests that the TTG originated by variable melting of a depleted gabbroid source at 10-12kbar, and the I-type tonalite-granodiorite suite by melting of a more enriched lithospheric source at c. 5 kbar. The voluminous intermediate and acidic I-types involved hybridisation with lower and middle crustal melts. The highly peraluminous S-type granites have isotopic and inherited zircon patterns similar to those of Cambrian supracrustal metasedimentary rocks deposited in the Pampean cycle, and were derived from them by local anatexis. Other major components of the S-type batholiths involved melting of deep crust and mixing with the I-type magmas, leading to an isotopic and geochemical continuum.

Linked references
Hide All

This list contains references from the content that can be linked to their source. For a full set of references and notes please see the PDF or HTML where available.

C. R. Bacon & T. H. Druitt 1988. Compositional evolution of the zoned calcalkaline magma chamber of Mount Mazama, Crater Lake, Oregon. Contributions to Mineralogy and Petrology 98, 224–56.

A. Castro , A. E. Patiño Douce , L. G. Corretgé , J. D. de la Rosa , M. El-Biad & H. El-Hmidi 1999. Origin of peraluminous granites and granodiorites, Iberian massif, Spain: an experimental test of granite petrogenesis. Contributions to Mineralogy and Petrology 135, 255–76.

W. Compston , I. S. Williams , J. L. Kirschvink , Zhang Zichao & Ma Guogan 1992. Zircon U-Pb ages from the early Cambrian time-scale. Journal of the Geological Society of London 149, 171184.

S. M. DeBari 1994. Petrogenesis and physical evolution of the Fiambalá gabbronorite, northwestern Argentina: syntectonic magmatism in the deep crust of a continental margin arc. Journal of Petrology 35, 679713.

H. Fujimaki , M. Tatsumoto & K. Aoki 1984. Partition coefficients of Hf, Zr and REE between phenocrysts and groundmasses. Proceedings of the fourteenth lunary and planetary science conference, Part 2. Journal of Geophysical Research 89, Suppl. B66272.

M. A. Galliski , A. Toselli & J. Saavedra 1990. Petrology and geochemistry of the Cachi high-alumina trondhjemites, northwestern Argentina. In S. M. Kay & C. W. Rapela (eds) Plutonism from Antarctica to Alaska, Geological Society of America Special Paper 241, 91100.

F. Lucassen , S. Lewerenz , G. Franz , J. Viramonte & K. Mezger 1999. Metamorphism, isotopic ages and composition of lower crustal granulite xenoliths from the Cretaceous Salta Rift, Argentina. Contributions to Mineralogy and Petrology 134, 325–41.

W. P. Nash & H. R. Crecraft 1985. Partition coefficients of trace elements in silicic magmas. Geochimica et Cosmochimica Acta 49, 2309–22.

R. J. Pankhurst , C. W. Rapela , J. Saavedra , E. Baldo , J. Dahlquist , I. Pascua & C. M. Fanning 1998. The Famatinian magmatic are in the central Sierras Pampeanas: an Early-to-Middle Ordovician continental arc on the Gondwana margin. In R. J. Pankhurst & C. W. Rapela (eds) The Proto-Andean Margin of Gondwana, Special Publications of the Geological Society of London 142, 343–67.

C.W. Rapela , A. Toselli , L. Heaman & J. Saavedra 1990. Granite plutonism of the Sierras Pampeanas: An inner cordilleran Paleozoic arc in the southern Andes. In S. M. Kay & C. W. Rapela (eds) Plutonism from Antarctica to Alaska, Geológical Society of America Special Papers 241, 7790.

C. W. Rapela , B. Coira , A. Toselli & J. Saavedra 1992. The Lower Paleozoic magmatism of southwestern Gondwana and the evolution of the Famatinian orogene. International Geology Review 34, 1081–142.

C. W. Rapela , R. J. Pankhurst , C. Casquet , E. Baldo , J. Saavedra , C. Galindo and C. M. Fanning 1998. The Pampean Orogeny of the southern proto-Andes: evidence for Cambrian continental collision in the Sierras de Córdoba. In R. J Pankhurst & C. W. Rapela (eds) The Proto-Andean Margin of Gondwana, Special Publications of the Geological Society of London 142, 181217.

J. Saavedra , E. Pellitero-Pascual , J. N. Rossi de Toselli & A. J. Toselli 1992. Magmatic evolution of the Cerro Toro granite: a complex Ordovician pluton of northwestern Argentina. Journal of South American Earth Sciences 5, 2132.

J. Saavedra , A.J. Toselli , J. Rossi , E. Pellitero & F. Durand 1998. The Early Palaeozoic magmatic record of the Famatina system: a review. In R. J Pankhurst & C. W. Rapela (eds) The Proto-Andean Margin of Gondwana, Special Publications of the Geological Society of London 142, 283–95.

D. M. Shaw 1970. Trace element fractionation during anatexis. Geochimica et Cosmochimica Acta 34, 237–43.

W. Springer & H. A. Seck 1997. Partial fusion of basic granulites at 5-15 kbar: implications for the origin of TTG magmas. Contributions to Mineralogy and Petrology 127, 3045.

S. Sun & W. F. McDonough 1989. Chemical and isotopic systematics of oceanic basalts: implications for mantle compositions. In A. D. Saunders & M. J. Norry (eds) Magmatism in the Ocean Basins, Special Publications of the Geological Society of London 42, 313345.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Earth and Environmental Science Transactions of The Royal Society of Edinburgh
  • ISSN: 1755-6910
  • EISSN: 1755-6929
  • URL: /core/journals/earth-and-environmental-science-transactions-of-royal-society-of-edinburgh
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Full text views

Total number of HTML views: 0
Total number of PDF views: 1 *
Loading metrics...

Abstract views

Total abstract views: 68 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 29th May 2017. This data will be updated every 24 hours.