Volume 18 1975

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Browsing Volume 18 1975 by Keyword "climate change"

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    Palyno-stratigraphy of the lower Karroo sequence in the central Sebungwe District, Mid-Zambezi Basin, Rhodesia
    (Bernard Price Institute for Palaeontological Research, 1975) Falcon, Rosemary S
    Hart (1962) was the first to discuss seriously the subject "palynology-key to stratigraphy" with regard to Southern Africa. Since then a number of publications have appeared on African Karroo palynology. However, to date only one large scale microfloral zonation scheme has been proposed -that of Hart (1967). In this, four major palynofloristic zones were outlined for Lower Karroo (Permian) sequences, drawn from surface and sub-surface material in South and Central Africa. Another scheme, dividing the Permian into eight zones in S. Africa (Great Karroo Basin) , is as yet unpublished (Anderson, in press). In an attempt to apply palynology to the problems of geological correlation and relative age determinations, specifically in the field of coal exploration in Rhodesia, a standard section in the form of one borehole, the Matabola Flats borehole, well-sited, deep and with apparently continuous deposition was chosen for palynological biostratigraphic analysis. Fifty-five miospore genera and ninety-eight species have been recognised in this study. Their systematic descriptions and statistical analyses are published elsewhere, Falcon 1975 a, b. Detailed analysis of the forty-eight productive samples show large scale micro-floral changes up the stratigraphic column. Four major assemblage zones and eight assemblage sub-zones are herein proposed, thereby expanding by four the palynofloristic zones of Hart.
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    Planktonic foraminifera and calcareous nannofossils at the Cretaceous-Tertiary contact in Zululand
    (Bernard Price Institute for Palaeontological Research, 1975) Stapleton, R P
    Assemblages of planktonic foraminifera and calcareous nannofossils for the Maestrichtian and Danian of Zululand are listed and illustrated. The Globotruncana gansseri and G. mayorensis foraminiferal zones are present in the Maestrichtian. The Globigerina triloculinoides and Globorotalia compressa foraminiferal subzones are present in the Danian. The Maestrichtian in this area cannot be subdivided on the basis of calcareous nannofossils. Danian nannofossil zones present are those of Cruciplacolithus tenuis and Chiasmolithus danicus . The Cretaceous-Tertiary faunal extinctions are briefly discussed and it is concluded that lowered temperatures were a factor in this extinction.