Cretaceous dinoflagellate cyst stratigraphy of the Höllviken 1 well, Scania, Southern Sweden
Abstract: The main aim of this thesis was to develop an improved biostratigraphical subdivision for part of the Lower and Upper Cretaceous section (Albian to Santonian) of Scania, Southern Sweden. Earlier attempts at biostratigraphic zonation within the sequence Cenomanian to Coniacian based on other micro- and macrofossils have proven difficult due to an impoverished fauna. In this study, dinoflagellate cysts were chosen because their abundancy and diversity in marine depositional sequences generally offers significantly improved resolution and a better potential for a broad correlation with other sequences of similar age.This zonation is based on borehole material from the Höllviken 1 well, Scania, southernmost Sweden, and covers the interval 1002-1286 m. The lower part consists of a black shale 1 m in thickness, which is overlain by a 52 m thick sandstone. A more than 200 m thick limestone sequence is present above the sandstone. Forty-one samples were prepared using standard palynological methods and examined using light microscopy.Most samples studied contained a rich and diverse dinoflagellate cyst flora; 81 different genera, 154 species and 12 subspecies were identified. The stratigraphical ranges of selected dinoflagellate cysts are discussed on the basis of existing literature. Based on dinoflagellate cysts, it was possible to divide the core sequence into five chronostratigraphical units that are of Albian, Cenomanian, Turonian, Coniacian and Santonian age respectively.A detailed dinoflagellate cyst rangechart for the Albian to the Santonian interval is presented (Enclosure 2).
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