Early Albian palynoflora of ODP Hole 120-750B

• Main Authors: Mohr, Barbara A R, Gee, Carole T
• Format: Dataset
• Language: English
• Published: PANGAEA 1992
• Subjects: 120-750B; DRILL; Drilling/drill rig; Joides Resolution; Leg120; Ocean Drilling Program; ODP; South Indian Ridge; South Indian Ocean; Indian; Kerguelen; Kerguelen Islands; New Zealand
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.758092; https://doi.org/10.1594/PANGAEA.758092

A well-preserved, diverse sporomorph flora of over 60 species has been found in Cores 120-750B-12W through -14R from the Southern Kerguelen Plateau. Analysis of the flora indicates that the terrestrial sediments overlaying the basaltic basement are late Early Cretaceous in age. Ranges of the sporomorphs in other parts of Gondwana and the morphology and paucity of angiosperm pollen grains confine the age of this section to the early to possibly early middle Albian. The Albian palynomorph assemblages in Hole 750B are composed primarily of fern spores and podocarpaceous pollen, and show most similarity to those from southern Australia. Changes in the flora through time reflect the successional vegetation changes on barren volcanic islands, beginning with high percentages of colonizing ferns and maturing into conifer (podocarp) forests. The flora shows some signs of endemism, which may be a result of the isolated position of the Kerguelen Islands during the Early Cretaceous. This endemism is expressed by high percentages of a distinctive monosulcate pollen species Ashmoripollis woodywisei n.sp. of pteridosperm or cycadophytean origin, and by a thick-walled, monosulcate angiosperm pollen species of the genus Clavatipollenites. The climatic conditions were probably cool to temperate (mean annual temperature approximately 7°-12°C) and humid (annual rainfall >1000 mm), analogous to modern Podocarpus-dominated forests in New Zealand and in South American mountain regions.