Relationships high grade syn-orogenic plutons and supracrustal rocks in an attractive orogen – Ribeira buckle instance-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 D_1+dos syntectonic leucosome from both basement and supracrustals, and defined a ca. 5step 30 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 (D₁₊₂) and was folded by the megascale F₃-folds ( Fig. 4E).

In the event one of those plutons mix-cut the CFTD with its NW idea, the Silva Jardim Pluton, old at 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 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. ).

In the adjacent Chinese language Terrane ( Figs. 2 and you can step three), there are even metamorphic age of california. 550 – 510 Ma ( Schmitt mais aussi al. 2004 Schmitt Roentgen.S., Trouw Roentgen.An effective.J., Van Schmus W.R., Pimentel M.M. 2004. Late amalgamation regarding main section of Western Gondwana: the latest geochronological study as well as the characterization out of an excellent Cambrian collisional orogeny regarding Ribeira Strip (SE Brazil). Precambrian Browse , -61. , 2012a Schmitt R.S., Mendes J.C., Peternel R., Silva L.C., Dantas Elizabeth.L. 2012a. : SSAGI, Medellin, Colombia. ; Fernandes ainsi que al. 2015 Fernandes Grams.L., Schmitt Roentgen.S., Bongiolo E., Mendes J.C., Basei M. 2015. Unraveling the tectonic evolution regarding a Neoproterozoic-Cambrian energetic margin from the Ribeira Orogen (SE Brazil): U-Pb and you may Lu-Hf provenance investigation. Precambrian Browse , -360. ). In addition, some plutons that have ages regarding 510 to 480 Ma intrude it terrane as they are interpreted as blog post-tectonic ( Valeriano ainsi que al. 2011 Valeriano C.M., Tupinamba Yards., Simonetti A good., Heilbron Meters., Almeida J.C.H., Eirado L.G. 2011. U-Pb La-MC-ICPMS geochronology out of Cambro-Ordovician post-collisional granites of your own Ribeira buckle, the southern part of Brazil: terminal Brasiliano magmatism within the central Gondwana supercontinent. Diary regarding Southern Western World Sciences , -428. ). 2 and step 3) ( Moraes 2009 Moraes J.M. 2009. Geologia perform Granito Silva Jardim (RJ): Implicacoes na evolucao tectonica 2 Terrenos Chinese language elizabeth Cabo Frio. Master Thesis UERJ. 65 p. ). It pluton presents an established igneous foliation which is thought a late-collisional magmatic system ( Moraes 2009 Moraes J.M. 2009. Geologia carry out Granito Silva Jardim (RJ): Implicacoes na evolucao tectonica dos Terrenos Chinese language e Cabo Frio. Grasp Thesis UERJ. 65 p. ). Brand new youngest magmatic intrusions entered on CFTD when you look at the Paleozoic is article tectonic pegmatites and you may granites out-of california. 440 Ma dated having U-Pb in the zircon ( Schmitt ainsi que al. 2004 Schmitt R.S., Trouw R.An effective.J., Van Schmus W.R., Pimentel Meters.M. 2004. Later amalgamation about main section of West Gondwana: new geochronological analysis together with characterization out-of a beneficial Cambrian collisional orogeny in the Ribeira Belt (SE Brazil). Precambrian Search , -61. , Bongiolo et al. 2015 Bongiolo E., Renac C., D’Almeida de- Toledo P., Schmitt Roentgen.S., Faulstich senior friend finder Гјcretsiz uygulama F.R.L., Mexias , Silva F.P.C. 2015. Resource of pegmatites and you can liquids within Ponta Negra (RJ, Brazil) during the later- to create-collisional stages of your own Gondwana Installation. Lithos , -275. ).