18 research outputs found

    Morphological variation and distribution of the Tournaisian (Early Mississippian) miospore Waltzispora lanzonii DAEMON 1974

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    Mississippian strata of the Amazonas Basin, northern Brazil, contain abundant and diverse assemblages of miospores, many of considerable stratigraphie importance. These include an acavate trilete species - Waltzispora lanzonii - which is the subject of the present account. Based on numerous specimens from the Tournaisian (Lower Mississippian) Oriximiná Formation, the morphology of the more typical and also the relatively rare, aberrant representatives of W. lanzonii is illustrated and described in detail. Current and previously published data indicate that the species is restricted palaeogeographically to north-northwest Gondwana; i.e., incorporating parts of presentday northern Brazil, Peru, and the Sahara region of Algeria and Libya. Chronostratigraphically, W. lanzonii is characteristic of and perhaps entirely confined to Tournaisian strata, although the possibility exists that it may extend slightly higher, into the Visean. However, rare occurrences of the species in upper Visean strata are considered to be a probable consequence of reworking
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