Early Jurassic miospores from Ferrar Group of Carapace Nunatak, South Victoria Land, Antarctica

Along the Transantarctic Mountains, the siliciclastic foreland basin deposits of the Beacon Supergroup and the effusive rocks of the Ferrar Group overlay the pre-Devonian metamorphic basement. The Ferrar Group at Carapace Nunatak is composed of fluvial volcanic sandstones of the Carapace Sandstone Formation, which is overlain by the volcanic flows and breccias of the Kirkpatrick Basalt Formation. Fossiliferous horizons are present in both formations. Palynological analyses have been carried out on fifteen samples collected in marly-silty horizons within the Carapace Sandstone and Kirkpatrick Basalt formations. Samples from the Carapace Sandstone Formation contain a scarce but quite well preserved palynoflora, which is orange to light brown in colour. The spore-pollen assemblages lack dominant species and are very similar in composition. The stratigraphically significant taxa Corollina torosa and Podosporites variabilis are present. The two samples from the Kirkpatrick Basalt Formation contain a very rich microflora dominated by Corollina species (mainly C. torosa) and Exesipollenites tumulus. Some representatives of the genus Callialasporites are also present. Comparisons with previous Carapace Nunatak and Antarctic palynological studies are discussed. The Australian Jurassic biostratigraphic zonation suggests a Late Sinemurian to basal Pliensbachian age for the Carapace Sandstone Formation and a Pliensbachian age for the basal part of the Kirkpatrick Basalt Formation, thus implying a revision of the stratigraphy and correlation between the formations in the Transantarctic mountains. (c) 2006 Elsevier B.V. All rights reserved. Along the Transantarctic Mountains, the siliciclastic foreland basin deposits of the Beacon Supergroup and the effusive rocks of the Ferrar Group overlay the pre-Devonian metamorphic basement. The Ferrar Group at Carapace Nunatak is composed of fluvial volcanic sandstones of the Carapace Sandstone Formation, which is overlain by the volcanic flows and breccias of the Kirkpatrick Basalt Formation. Fossiliferous horizons are present in both formations. Palynological analyses have been carried out on fifteen samples collected in marly-silty horizons within the Carapace Sandstone and Kirkpatrick Basalt formations. Samples from the Carapace Sandstone Formation contain a scarce but quite well preserved palynoflora, which is orange to light brown in colour. The spore-pollen assemblages lack dominant species and are very similar in composition. The stratigraphically significant taxa Corollina torosa and Podosporites variabilis are present. The two samples from the Kirkpatrick Basalt Formation contain a very rich microflora dominated by Corollina species (mainly C. torosa) and Exesipollenites tumulus. Some representatives of the genus Callialasporites are also present. Comparisons with previous Carapace Nunatak and Antarctic palynological studies are discussed. The Australian Jurassic biostratigraphic zonation suggests a Late Sinemurian to basal Pliensbachian age for the Carapace Sandstone Formation and a Pliensbachian age for the basal part of the Kirkpatrick Basalt Formation, thus implying a revision of the stratigraphy and correlation between the formations in the Transantarctic mountains. (c) 2006 Elsevier B.V. All rights reserved.