   Miospores from Ordovician-Silurian Argentinean basins: evolution and relationships with other South American basins; ; Steemans, Philippe  Conference (2011, September) Detailed reference viewed: 15 (4 ULg) Siluro-Devonian miospore biostratigraphy of the Urubu River area, western Amazon Basin, northern BrazilSteemans, Philippe ; ; in Geobios (2008), 41 Detailed reference viewed: 11 (2 ULg)Silurian and Early Lower Devonian miospores from South AmericaSteemans, Philippe ; Conference (2006) Detailed reference viewed: 1 (0 ULg)Lochkovian (earliest Devonian) miospores from the Solimoes Basin, northwestern Brazil; ; Steemans, Philippe in Review of Palaeobotany and Palynology (2005), 133(1-2), 91-113 Eighteen core samples from PETROBRAS well 1-JD-1-AM (Jandiatuba area. Solimoes Basin. northwestern Brazil) have been studied for miospores. Fifty-three species are identified. This assemblage is ... [more ▼] Eighteen core samples from PETROBRAS well 1-JD-1-AM (Jandiatuba area. Solimoes Basin. northwestern Brazil) have been studied for miospores. Fifty-three species are identified. This assemblage is tentatively correlated with the Z Phylozone of the BZ Oppel Zone (Steemans, P., 1989. Palynostratigraphie de l'Eodevonien dans l'ouest de l'Europe. Professional Paper. Memoires Explicatifs pour les Caries Geologiques and Mineralogiques de la Belgique, 27, pp. 453.), dated late Lochkovian, This is in accordance with previous age determinations based on chitinozoans and acritarchs. Numerous representatives of the miospore genus Dictyotriletes are observed. These enable recognition of the Dictyotriletes emsiensis morphon. an informal classification unit which includes Dictyotriletes granulatus, D. emsiensis, Dictyotriletes cf. subgranifer, specimens previously misassigned to D. subgranifer and some Dictyotriletes spp. provisionally left in open nomenclature. Since all intermediate forms from typical D. granulatus to typical D. emsiensis coexist. it is currently difficult to determine the base of "F" Interval Biozone in South America as originally defined in Western Europe. It is suggested. therefore. that the base of the "Ems" Biozone defined in Brazil cannot be correlated with the base of die "E" Biozone. Instead. it be included in an interval of uncertainty ranging from the European "Si" to "E" Biozones. Indeed. the underlying "NsZ" Biozone from South America, contains species not known below the "Si" Biozone. Here, the D. emsiensis morphon Assemblage Zone is erected, which may, be coeval with the "N" through "E" Biozones of Western Europe. The PISA palynoflora from the Parana Basin is also attributed to this new biozone. However, in the absence of species observed in the "BZ" Biozone (and also in the Solimoes Basin). the PISA assemblage could be somewhat older than that of well 1-JD-1-AM. (C) 2004 Elsevier B.V. All rights reserved. [less ▲] Detailed reference viewed: 51 (2 ULg)Miospore assemblages from the Silurian-Devonian boundary, in borehole A1-61, Ghadamis Basin, Libya; Steemans, Philippe in Review of Palaeobotany and Palynology (2002, April), 118(1-avr Sp. Iss. SI), 397-421 Well preserved and diversified miospore assemblages have been recorded from a relatively continuous sequence in borehole A1-61 which spans the Silurian-Devonian boundary in the northwestern part of the ... [more ▼] Well preserved and diversified miospore assemblages have been recorded from a relatively continuous sequence in borehole A1-61 which spans the Silurian-Devonian boundary in the northwestern part of the Ghadamis Basin, Libya. The sequence is represented by early Devonian Lochkovian beds of the Tadrart Formation that transgress onto the Silurian Ludlow-Pridoli beds of the upper part of the 'Alternances Argilo-greseuses' Formation. The present work demonstrates a succession of miospore assemblages from closely sampled layers that have been stratigraphically dated as Ludlow-middle Pridoli and early Lochkovian by chitinozoans and acritarchs. Over 80 species of cryptospores and trilete spores have been identified. Modified detailed morphological interpretations are given. The miospore assemblages are correlated with miospore zonation schemes established for the type sequences of the Welsh Borderland, and those previously described from Libya. Early occurrences of some species as Streelispora newportensis on the western Gondwana plate, are put forward by comparison with the Old Red Sandstone continent. Phytogeographic and palaeobotanic implications based on these observations are discussed. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲] Detailed reference viewed: 28 (5 ULg) |
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