Australian Palinomorphs From The Buya Formation Of The Sula Island

Abstract

This research has proved the occurrence of pre-Tertiary palynomorphs within the Buya Formation of the Sula Island. Most palynomorphs have Australian affi nity and appear in most Mesozoic basins in Australia and in Papuan Basin of Papua New Guinea. The palynomorph assemblage mostly consists of spores as well as dinofl agellates. Three micro-fl ora zones can be defi ned referring to the existing index spores, including (from older to younger zone) Contignisporites cooksoniae zone, Murospora fl orida zone and Retitriletes watheroensis zone. Meanwhile, four dinofl agellate zones enable to be constructed such as (from older to younger zone) Caddasphaera halosa zone, Wanaea clathrata-Wanaea indotata zone, Dingodinium swanense zone and Criboperidinium perforans zone-younger zone. Both zonations suggest that the age of the Buya Formation is Middle to Late Jurrasic or Bathonian to Tithonian. From the palaeobiogeographic point of view, the similarity between palynomorphs from the Buya Formation of the Sula Island and those from the Mesozoic sediment of Australia suggests land connection between both areas during Middle to Late Jurassic. It suggests that, during this age, the study area attached the Australian Continent which was situated far South from the equatorial. The study area appears in its recent position during Neogene.