Dating high-grade syn-orogenic plutons and you can supracrustal rocks inside the an attractive orogen – Ribeira belt circumstances-analysis

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The deformation and high grade metamorphism responsible for the tectonic inversion of the sedimentary basin is attributed to an orogenic event of Cambrian age. Schmitt et al. (200cuatro Schmitt R.S., Trouw R.A.J., Van Schmus W.R., Pimentel M.M. 2004. Late amalgamation in the central part of West Gondwana: new geochronological data and the characterization of a Cambrian collisional orogeny in the Ribeira Belt (SE Brazil). Precambrian Research , -61. , 2008b Schmitt R.S., Trouw R.A.J., Van Schmus W.R., Passchier C.W. 2008b. Cambrian orogeny in the Ribeira Belt (SE Brazil) and correlations within West Gondwana: ties that bind underwater. : Pankhurst R.J., Trouw R.A.J., Brioto Neves B.B., De Wit M.J. (eds.) West Gondwana: Pre-Cenozoic Correlations across the South Atlantic Region . Geological Society, London , Special Publications, -296. ) dated the D₁₊₂ syntectonic leucosome from both basement and supracrustals, and defined a ca. 530 Ma tectonometamorphic event related to a convergent margin that culminated with a continental collision (Buzios Orogeny). This partial melt product was generated during the metamorphic peak (D_1+dos) and was folded by the megascale F₃-folds ( Fig. 4E).

No matter if one among them plutons cross-slice the CFTD in its NW suggestion, the newest Silva Jardim Pluton, old from the 505 Ma ( Figs

In the basement, the lower intercepts of the U-Pb discordia lines are in the interval between 600 and 450 Ma, consistent with this event ( Schmitt et al. 2004 Schmitt R.S., Trouw R.A.J., Van Schmus W.R., Pimentel M.M. 2004. Late amalgamation in the central part of West Gondwana: new geochronological data and the characterization of a Cambrian collisional orogeny in the Ribeira Belt (SE Brazil). Precambrian Research , -61. , 2008b Schmitt R.S., Trouw R.A.J., Van Schmus W.R., Passchier C.W. 2008b. Cambrian orogeny in the Ribeira Belt (SE Brazil) and correlations within West Gondwana: ties that bind underwater. : Pankhurst R.J., Trouw R.A.J., Brioto Neves B.B., De Wit M.J. (eds.) West Gondwana: Pre-Cenozoic Correlations across the South Atlantic Region . Geological Society, London , Special Publications, -296. ). The metamorphic rims of the Paleoproterozoic zircon grains in the shear zones are dated at ca. 505 Ma ( Schmitt et kik usernames sexy girls al. 2008b Schmitt R.S., Trouw R.A.J., Van Schmus W.R., Passchier C.W. 2008b. Cambrian orogeny in the Ribeira Belt (SE Brazil) and correlations within West Gondwana: ties that bind underwater. : Pankhurst R.J., Trouw R.A.J., Brioto Neves B.B., De Wit M.J. (eds.) West Gondwana: Pre-Cenozoic Correlations across the South Atlantic Region . Geological Society, London , Special Publications, -296. ). In the supracrustals, all metamorphic minerals are formed during the Cambrian (ca. 530 Ma). Zircon, monazite, sphene and rutile were dated and yielded a metamorphic time interval between 525 and 510 Ma for the eastern CFTD and 505 – 490 Ma for the western CFTD ( Schmitt et al. 2004 Schmitt R.S., Trouw R.A.J., Van Schmus W.R., Pimentel M.M. 2004. Late amalgamation in the central part of West Gondwana: new geochronological data and the characterization of a Cambrian collisional orogeny in the Ribeira Belt (SE Brazil). Precambrian Research , -61. ). The occurrence of a late F₄-reclined megascale fold in the western region could partially explain this ( Fig. 3). These younger ages could indicate that units in this region stayed deeper in the crust and the D₄ deformational phase would bring them up later. The cooling rate calculated for the eastern part of CFTD is rapid until ca. 510 Ma (more than 20 o C/Ma), and after this diminishes to 5 – 10 o C/Ma ( Schmitt et al., 2004 Schmitt R.S., Trouw R.A.J., Van Schmus W.R., Pimentel M.M. 2004. Late amalgamation in the central part of West Gondwana: new geochronological data and the characterization of a Cambrian collisional orogeny in the Ribeira Belt (SE Brazil). Precambrian Research , -61. ).

On adjacent China Terrane ( Figs. dos and step three), there are even metamorphic period of ca. 550 – 510 Ma ( Schmitt et al. 2004 Schmitt Roentgen.S., Trouw Roentgen.An excellent.J., Van Schmus W.R., Pimentel Yards.M. 2004. Late amalgamation from the central section of Western Gondwana: the fresh geochronological data plus the characterization out of a Cambrian collisional orogeny in the Ribeira Strip (SE Brazil). Precambrian Search , -61. , 2012a Schmitt Roentgen.S., Mendes J.C., Peternel Roentgen., Silva L.C., Dantas E.L. 2012a. : SSAGI, Medellin, Colombia. ; Fernandes ainsi que al. 2015 Fernandes G.L., Schmitt Roentgen.S., Bongiolo Age., Mendes J.C., Basei M. 2015. Unraveling the newest tectonic evolution from a great Neoproterozoic-Cambrian effective margin regarding Ribeira Orogen (SE Brazil): U-Pb and you may Lu-Hf provenance research. Precambrian Look , -360. ). Furthermore, some plutons which have many years out-of 510 so you can 480 Ma intrude that it terrane and are generally interpreted since the post-tectonic ( Valeriano mais aussi al. 2011 Valeriano C.Meters., Tupinamba M., Simonetti An excellent., Heilbron Yards., Almeida J.C.H., Eirado L.G. 2011. U-Pb Los angeles-MC-ICPMS geochronology of Cambro-Ordovician article-collisional granites of one’s Ribeira belt, the southern part of Brazil: critical Brasiliano magmatism into the main Gondwana supercontinent. Journal out-of Southern area Western Environment Sciences , -428. ). dos and you will step three) ( Moraes 2009 Moraes J.Yards. 2009. Geologia manage Granito Silva Jardim (RJ): Implicacoes na evolucao tectonica dos Terrenos China age Cabo Frio. Learn Thesis UERJ. 65 p. ). It pluton gifts a type igneous foliation which can be noticed a great late-collisional magmatic system ( Moraes 2009 Moraes J.Yards. 2009. Geologia would Granito Silva Jardim (RJ): Implicacoes na evolucao tectonica dos Terrenos China age Cabo Frio. Master Thesis UERJ. 65 p. ). This new youngest magmatic intrusions joined regarding the CFTD when you look at the Paleozoic are article tectonic pegmatites and granites out-of california. 440 Ma old which have U-Pb from inside the zircon ( Schmitt et al. 2004 Schmitt R.S., Trouw R.An effective.J., Van Schmus W.R., Pimentel M.Yards. 2004. Later amalgamation in the central part of West Gondwana: the new geochronological analysis additionally the characterization from a good Cambrian collisional orogeny from the Ribeira Buckle (SE Brazil). Precambrian Search , -61. , Bongiolo mais aussi al. 2015 Bongiolo Elizabeth., Renac C., D’Almeida de- Toledo P., Schmitt Roentgen.S., Faulstich F.Roentgen.L., Mexias , Silva F.P.C. 2015. Resource away from pegmatites and drinks on Ponta Negra (RJ, Brazil) through the late- to share-collisional level of one’s Gondwana Installation. Lithos , -275. ).