Cretaceous carbonate platforms - emerging concepts and open problems
The Cretaceous is a time of both spectacular growth and abrupt demise of carbonate platforms. Tectono-eustatic rise of sea level coupled with sediment-starvation in the ocean basins produced exceptionally high platforms. Because platform slopes steepen with height whereas siliciclastic slopes do not, the flanks of these high-rising platforms were onlapped by more gently dipping siliciclastics when the platforms ceased to grow. Future studies will have to separate these termination unconformities from the geometrically similar lowstand unconformities. Simultaneously, a carbonate sea level curve should be constructed solely from the record of the platform tops and compared with the onlap curves of seismic stratigraphy. The abrupt demise of Cretaceous platforms is even more remarkable than their rapid growth. In the Valanginian, the Aptian, the late Albian, the late Cenomanian, and the Turonian, platforms were drowned or reduced in size. The mid-Cretaceous events affected platforms in all major oceans and point to a global crisis of carbonate platforms, probably caused by environmental change such as oceanic anoxic events. A worldwide study is required to date these events and search for their causes in the record of life, climate, ocean circulation, and ocean chemistry. A third field of future research is the record of paleoclimate in the tidal flats and lagoons of the platforms on the northern and southern margins of Tethys. Climate modeling has identified this zone as a particularly sensitive switch in the ocean-atmosphere system of the Cretaceous.
- Research Organization:
- Free Univ., Amsterdam (Netherlands)
- OSTI ID:
- 5793693
- Report Number(s):
- CONF-880301-
- Journal Information:
- AAPG Bull.; (United States), Vol. 72:2; Conference: Annual meeting of the American Association of Petroleum Geologists, Houston, TX, USA, 20-23 Mar 1988
- Country of Publication:
- United States
- Language:
- English
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