Relationship high-grade syn-orogenic plutons and you can supracrustal stones in the a hot orogen – Ribeira strip instance-analysis

1 Ağustos 2023

Relationship high-grade syn-orogenic plutons and you can supracrustal stones in the a hot orogen – Ribeira strip 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 D1+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+dos) and was folded by the megascale F3-folds ( Fig. 4E).

Though one among them plutons mix-cut the CFTD within the NW idea, the fresh Silva Jardim Pluton, dated during 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 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. ).

Regarding the surrounding Oriental Terrane ( Figs. dos and you can step three), there are even metamorphic period of california. 550 – 510 Ma ( Schmitt mais aussi al. 2004 Schmitt Roentgen.S., Trouw R.A good.J., Van Schmus W.R., Pimentel Meters.M. 2004. Late amalgamation in the main section of Western Gondwana: the fresh geochronological investigation additionally the characterization away from a great Cambrian collisional orogeny from the Ribeira Belt (SE Brazil). Precambrian Look , -61. , 2012a Schmitt Roentgen.S., Mendes J.C., Peternel Roentgen., Silva L.C., Dantas Age.L. 2012a. : SSAGI, Medellin, Colombia. ; Fernandes et al. 2015 Fernandes G.L., Schmitt Roentgen.S., Bongiolo E., Mendes J.C., Basei M. 2015. Unraveling this new tectonic advancement out-of a great Neoproterozoic-Cambrian productive margin from the Ribeira Orogen (SE Brazil): U-Pb and Lu-Hf provenance study. Precambrian Look , -360. ). Furthermore, several plutons having age out of 510 to help you 480 Ma intrude which terrane and so are translated because the article-tectonic ( Valeriano mais aussi al. 2011 Valeriano C.Yards., 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 blog post-collisional granites of one’s Ribeira gear, the southern part of Brazil: terminal Brasiliano magmatism in the central Gondwana supercontinent. Diary regarding Southern area American Earth Sciences , -428. ). dos and you will 3) ( Moraes 2009 Moraes J.M. 2009. Geologia create Granito Silva Jardim (RJ): Implicacoes na evolucao tectonica dos Terrenos Oriental age Cabo Frio. Master Thesis UERJ. 65 p. ). That it pluton gift suggestions a situated igneous foliation that’s noticed a good late-collisional magmatic muscles ( Moraes 2009 Moraes J.Yards. 2009. Geologia carry out Granito Silva Jardim (RJ): Implicacoes na evolucao tectonica 2 Terrenos Oriental age Cabo Frio. Learn Thesis UERJ. 65 p. ). The fresh youngest magmatic intrusions joined on the CFTD for the Paleozoic are blog post tectonic pegmatites and you may granites out-of ca. 440 Ma old having U-Pb from inside the zircon ( Schmitt et al. 2004 Schmitt R.S., Trouw R.Good.J., Van Schmus W.Roentgen., Pimentel M.M. 2004. Later amalgamation throughout the central section of Western Gondwana: the fresh geochronological research additionally the characterization off a good Cambrian collisional orogeny throughout the Ribeira Buckle (SE Brazil). Precambrian Lookup , -61. , Bongiolo ainsi que al. 2015 Bongiolo E., Renac C., D’Almeida de- Toledo P., Schmitt R.S., Faulstich F.Roentgen.L., Mexias , Silva F.P.C datingmentor.org/indian-dating/. 2015. Resource regarding pegmatites and you will liquids from the Ponta Negra (RJ, Brazil) through the later- to publish-collisional level of your own Gondwana System. Lithos , -275. ).

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