Upper Cretaceous calcareous nannofossils from Broken Ridge and Ninetyeast Ridge ...

• Main Author: Resiwati, Purtyasti
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 1991
• Subjects: Drilling/drill rig; Leg121; Joides Resolution; Ocean Drilling Program ODP; Southern Ocean; Weddell Sea
• Online Access: https://dx.doi.org/10.1594/pangaea.728987; https://doi.pangaea.de/10.1594/PANGAEA.728987

Drilling at Broken Ridge and Ninetyeast Ridge during Ocean Drilling Program Leg 121 yielded thick sections of Upper Cretaceous nannofossil-bearing sediments including calcareous chalk, limestone with chert, and volcanic ash.The upper Campanian to Maestrichtian assemblages from Broken Ridge are austral in nature, containing many of the endemic Southern Ocean forms observed from the Falkland Plateau, Weddell Sea, and the Kerguelen Plateau. The absence of the Lithraphidites praequadratus-L. quadratus lineage and significant overlap of the first-appearance datum of Nephrolithus frequens and the last-appearance datum of Reinhardtites levis negate direct use of temperate zonation schemes for these sediments: the austral zonation is more effective but has lower stratigraphic resolution. The upper Campanian to Maestrichtian of Ninetyeast Ridge contains both austral and tropical forms in different horizons; the modified zonation of Sissingh (1977) is most effective in age-dating these sediments.The Turonian-Santonian ... : Supplement to: Resiwati, Purtyasti (1991): Upper Cretaceous calcareous nannofossils from Broken Ridge and Ninetyeast Ridge, Indian Ocean. In: Weissel, J; Peirce, J; Taylor, E; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 121, 141-170 ...