Print this pageAbstract: Calibration of Marine and
Non-Marine Cretaceous 
Biostratigraphic
Frameworks on the African Margins
of the South Atlantic Ocean and Their Correlation to the South American
Margins
Chen, Y. Y.; Huang, T. C.; McLaughlin, P. P. - Exxon Exploration Co.
Synthesis of multi-fossil-group biostratigraphic
studies of the Cretaceous of central and West Africa permit us to establish
a preliminary, integrated biostratigraphy for marine and non-marine sediments
on the African margin of the south Atlantic Ocean. This zonation is based
on studies in Chad, Niger, Central Africa Republic, Angola, Ivory Coast,
and Senegal and is tied to a global chronostratigraphic standard. The findings
were compared with coeval zonations from South America (Brazil, Venezuela,
Colombia, Ecuador, and Peru) to establish preliminary correlations across
the Cretaceous south Atlantic Ocean.
Spores and pollen are a valuable tool for regional
correlation. They occur relatively continuously through the period and
are well represented in various sedimentary environments, both non-marine
and marine. We identified over forty morphologically distinctive and stratigraphically
restricted palynomorphs that divide the period into twenty-three zones.
For the Albian and younger section, the non-marine zonation is calibrated
to the chronostratigraphic standard based on coeval dinoflagellate, foraminifera,
and nannoplankton data.
Comparison between the palynomorph biostratigraphy
of West and central Africa with the published literature for Brazil suggests
that the biostratigraphic
frameworks of these areas are generally compatible.
Most variations are due to endemic species that constitute less than 20%
of the total assemblage or due to minor regional variations of the ranges
of a few forms.
AAPG Search and Discovery Article #90933©1998 ABGP/AAPG International Conference and Exhibition, Rio de Janeiro, Brazil