CTM - Artigos em revistas internacionais
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- First record of Permo-Triassic palynomorphs of the N'Condédzi sub-basin, Moatize-Minjova Coal Basin, Karoo Supergroup, MozambiquePublication . Galasso, Francesca; Pereira, Zélia; Fernandes, Paulo; Spina, Amália; Marques, JoãoABSTRACT: ermian-Triassic ages have been identified for the first time in the Karoo Supergroup of the N'Condedzi sub-basin, Moatize-Minjova Coal Basin, Mozambique. This transition was identified in a coal exploration borehole that penetrated the Matinde and Cadzi formations. The top of the Matinde Formation is dated latest Permian (Lopingian), and the Cadzi Formation is attributed to Triassic based on palynostratigraphy. The Lopingian age is established by the identification of three palyno-assemblages: Assemblage L1 based on the first occurrence (FO) of Guttulapollenites pollen, Assemblage L2 is marked by the FO of Thymospora pseudothiessenii, and Assemblage L3 is defined by the FO of Osmundacidites senectus. Triassic palynomorphs were identified for the first time in Mozambique (Karoo basins). The data allowed the identification of three assemblages: Assemblage T1 defined by the FO of Densoisporites nejburgii of Induan age, Assemblage T2 is marked by the FO of Platysaccus queenslandi and assigned to the Olenekian age, and Assemblage T3 is defined by the FO of Samaropollenites speciosus and Enzonalasporites vigens, indicating a Carnian age. No Middle Triassic rocks were identified, and the early Triassic sediments are overlain by sedimentary rocks of Carnian age, a hiatus that may correspond to an important tectonic event with uplift and erosion. This tectonic event is also suggested by the occurrence of common reworked Permian palynomorphs in the Carnian sedimentary rocks. These new data constrain the age of the Karoo Supergroup formations of Mozambique and contribute to improve the palaeoecological, palaeoclimatic evolution, and the palaeogeographic position of the Karoo Mozambique basins within the Gondwana supercontinent.
- Palynology of the Muarádzi sub-basin, Moatize-Minjova Coal Basin, Karoo Supergroup, MozambiquePublication . Pereira, Zélia; Fernandes, Paulo; Lopes, Gilda; Marques, João; Vaz, Maria; Costa, Marta; Correia, João; Castro, Lígia; Galasso, FrancescaABSTRACT: The detailed palynostratigraphic study of four boreholes in theMuarádzi sub-basin,Moatize-Minjova Coal Basin (MMCB) southeast of Moatize, allowed the assignment of relative ages to the stratigraphic units. Three assemblages were studied in detail and are assigned to the Lopingian. Assemblage L1 is characterized by the rich occurrence of Guttulapollenites and Weylandites. Assemblage L2 is defined on the first occurrence (FO) of abundant Thymospora pseudothiessenii together with Indotriradites niger, kraeuselisporites spp., Polypodiisporites mutabilis and Polypodiidites sp. Assemblage L3 is characterized by the first occurrence of Osmundacidites senectus together with the taxa described from the previous assemblages. Palynological correlation with other Karoo basins is discussed and three distinct palynostratigraphic events emerge based on the FO and abundance of key taxa (as for instance, FO of G. hannonicus, T. pseudothiensenii and O. senectus). A close palynological correlation between Mozambique (Moatize-Minjova Basin), Tanzania (Selous Basin), Zambia (mid-Zambezi Basin) and Madagascar palynoevents is established. This major region can be assigned to the northern Karoo-aged basins of southcentral Africa and the palynoevents can be correlated with Lopingian assemblages of Pakistan, India and some basins of East Antarctica. The southern Karoo-aged basins of south-central Africa, including South Africa and Zimbabwe, show different Lopingian palynoevents and a direct correlation is demanding. These palynological datamay open newperspectives for coal exploration in theMMCB as the coal deposits showawider stratigraphic distribution, reaching until the latest Lopingian.