Towards a New Genetic Classification of Carbonate Platforms Based on Their Basinal and Tectonic Settings in the Cenozoic
Dan Bosence
Royal Holloway University of London, Egham,
Surrey, England
The existing classifications of carbonate platforms into ramps and rimmed
shelves have value in describing platform margin morphology at any one time.
However they are less successful at categorising the entire morphology and
stratigraphy of carbonate platforms. A reassessment of Cenozoic carbonate
platforms indicates that their basinal and tectonic setting can be used to erect
a first-order, genetic classification of carbonate platforms. The basinal and
tectonic setting of carbonate platforms is shown to control their occurrence,
the overall 3-D platform morphology, the large-scale stratigraphic features and
depositional sequences. Climate, ocean chemistry and biological evolution
control grain types
, facies and some elements of platform margins but not the
larger-scale features. From a review of
well
-exposed outcropping and seismically
imaged Cenozoic platforms, it is proposed that eight
types
can currently be
recognised and characterised based on their basinal and tectonic setting:
Fault-Block, Salt Diapir, Subsiding Margin, Offshore Bank, Volcanic Pedestal,
Thrust-Top, Delta-Top and Foreland Margin carbonate platforms. These eight
types
are described using information from Cenozoic platforms worldwide and the
controls on their development are discussed. Many platform
types
(e.g. Subsiding
Margin, Offshore Bank, Salt Diapir, Thrust-Top and Foreland Margin) are typical
of particular classes of sedimentary basins, others (e.g. Fault-block, Volcanic
Pedestal and Delta-Top) are more widespread in their occurrence and occur in a
range of basin
types
. The value of this classification is that it is genetic
rather than morphological; the platform models can be used as templates to
characterise the details of less
well
exposed, or seismically imaged platforms.
AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005