U-Pb baddeleyite dating of the Proterozoic Pará de Minas dyke swarm in the São Francisco craton (Brazil) – implications for tectonic correlation with the Siberian, Congo and North China cratons

• U–Pb baddeleyite ages demonstrate the presence of three dyke generations within the NW-trending Pará de Minas swarm (São Francisco craton, South America), dated at ca. 1795 Ma (1798 ± 4, 1791 ± 7 and 1793 ± 18 Ma), ca. 1710 Ma (1702 ± 13 and 1717 ± 11 Ma) and 766 ± 36 Ma. These ages have implications for the São Francisco-Congo (SF-Congo) craton within the Rodinia and Columbia supercontinent configurations. At 1795 Ma, the Rio de la Plata craton (1790 ± 5 Ma Uruguayan dykes), Amazonian craton (1790–1780 Ma Avanavero LIP), Sarmatia (1789 ± 3 Ma Tomashgorod dyke), North Australia (1790 ± 4 Ma Hart dolerites) and the North China craton (1790–1770 Ma Taihang-Xiong’er event) could potentially have been “next-door neighbours” to the SF-Congo craton. Possible matches at 1710 Ma are the 1750–1700 Ma Bilyakchan-Ulkan complex and coeval dykes in the Siberian craton and the 1730 Ma Miyun dyke swarm in NCC. Given large uncertainties, the 766 ± 36 Ma age may be compared with the age of the 790 Ma Niquelândia complex in adjacent Goias state, the 799 Ma Gannakouriep dykes in the Kalahari craton, the 780 Ma Gunbarrel LIP of western Laurentia, the 760 Ma Mount Rogers LIP of eastern Laurentia and the 755 Ma Mundine Well event (western Australia). We propose a reconstruction in which the SF-Congo is attached to North China and Siberia, which existed from 1790 to 1380 Ma when SF-Congo and North China broke away from Siberia, and until 930 Ma when North China separated from SF-Congo.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Geologi (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Geology (hsv//eng)

Nyckelord

paleogeographic reconstructions

Pará de Minas swarm

São Francisco craton

U–Pb baddeleyite

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