Prof. David K. Watkins
Prof. David Harwood
Prof. Sherilyn Fritz
Date of this Version
Albasrawi, W. A. (2016). Early Miocene Quantitative Calcareous Nannofossil Biostratigraphy from the Tropical Atlantic. Unpublished Master’s Thesis, The University of Nebraska-Lincoln, Lincoln, Nebraska.
Quantitative analysis for the Lower Miocene of Ocean Drilling Program Hole 959A from the West African margin was performed to document all the calcareous nannofossil biostratigraphic events present. Combined with data from previous investigations of the Lower Miocene from the tropical Atlantic, this research identifies and tests the viability of markers used in current zonation scheme, identifies alternative markers for age boundaries, and examine statistically the most probable order of event in the Lower Miocene using the Ranking and Scaling method (RASC).
The examination of Hole 959A was performed on a 112 samples. Seven additional sites that collectively span the lower Miocene are used for the quantitative biostratigraphic analysis. These sites include DSDP Site 563 in the north central Atlantic (Maiorano and Monechi, 1998), Holes 897C, 898A, and 900A on the Iberian Abyssal Plain (De Kaenel and Villa, 1996),
Holes 960C and 960A on the Ivory Coast margin (Shafik et al., 1998), and DSDP Site 558 in the North central Atlantic (Parker et al., 1984).
In Hole 959A, all major zones and subzonal boundaries from CN1 to CN4 were identified, except for the boundary between Subzones CN1a and CN1b, using primary and secondary markers from Okada and Bukry (1980) zonation. All age boundaries were identified or closely estimated using the proper calcareous nannoplankton markers from the Chattian to Langhian stages.
The resultant list of events extracted from Hole 959A along with events from other seven sites were biostratigraphically examined in RASC. The well threshold is the only control parameter that was changed in order to select the appropriate control parameter. A well threshold of 4 was selected resulting in 22 events in the optimum sequence with 13 of which had a low standard deviation.
Advisor: David K. Watkins