Geochronological data from the Faxinal coal succession, southern Paraná Basin, Brazil: A preliminary approach combining radiometric U-Pb dating and palynostratigraphy
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- 作者：Margot Guerra-Sommer ; Miriam Cazzulo-Klepzig ; Rualdo Menegat ; Milton Luiz Laquintinie Formoso ; Miguel  ; ngelo Stipp Basei ; Eduardo Guimarã ; es Barboza ; Margarete Wagner Simas
- 关键词：U-Pb zircon dating ; Coal succession ; Paraná ; Basin ; Palynostratigraphy ; Sakmarian
- 刊名：Journal of South American Earth Sciences
- 出版年：2008
- 出版时间：March 2008
- 年：2008
- 卷：25
- 期：2
- 页码：246-256
- 全文大小：2996 K
文摘
A radiometric zircon age of 285.4 ± 8.6 Ma (IDTIMS U-Pb) is reported from a tonstein layer interbedded with coal seams in the Faxinal coalfield, Rio Grande do Sul, Brazil. Calibration of palynostratigraphic data with the absolute age shows that the coal depositional interval in the southern Paraná Basin is constrained to the Sakmarian. Consequently, the basal Gondwana sequence in the southern part of the basin should lie at the Carboniferous–Permian boundary, not within the Sakmarian as previously considered. The new results are significant for correlations between the Paraná Basin and the Argentinian Paganzo Basin (302 ± 6 Ma and 288 ± 7 Ma) and with the Karoo Basin, specifically with the top of the Dwyka Tillite (302 ± 3 Ma and 299.2 ± 3.2 Ma) and the lowermost Ecca Group (288 ± 3 Ma and 289.6 ± 3.8 Ma). The evidence signifies widespread latest Carboniferous volcanic activity in western Gondwana.