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This is the Home Page of a conferencepresented to Mesozoic and Cenozoic Sequence Stratigraphy of European Basins, CNRS-IFP, Dijon France, May 18-20, 1992, SEPM Special Publication N° 60.

If you click on the interlinks (underlined text and bots), you can navigate and you will find a text and the majority of the plates shown during these conference.

Four types of stratigraphic cycles of more than 10.000 years duration are recognizable within the stratigraphic record. They are (i) Continental Encroachments Cycles, (ii) Major Transgressive-Regressive Facies Cycles , (iii) Sequence Cycles and (iv) Parasequence Cycles. (i) Continental Encroachments Cycles are defined on the basis of the relative extent to which the continents are covered by sedimentary rocks at the time of deposition. These cycles have a duration greater than 50 My and are defined as first order. There are two major continental encroachment cycles in the Phanerozoic. One extends from the latest Proterozoic to the basal Triassic, and the more recent extends from the basal Triassic to the Present. First order cycles are produced by tectono-eustatic sea level changes corresponding to changes in ocean basin volume induced by continental break-up and aggregation. The bases of continental encroachment cycles are regional onlap surface that are associated with maximum basinward shifts of coastal onlap. The maximum marine transgressions within the continental encroachment cycles occur at the base of the Ordovician in the older cycle and near the base of he Middle Cretaceous Turonian age in the upper cycle. The peak Turonian transgression of the youngest cycle is commonly characterized on seismic data by a major downlap surface that separates the backstepping transgressive phase of the encroachment cycle from the forestepping regressive phase. Seismic examples illustrate the similarity of continental encroachment cycles on several different continents. The youngest continental encroachment cycle is represented by the smoothed long term sea-level curve of Haq et al., (1987) chart. (ii) Major Transgressive Regressive Facies cycles are defined on the basis of changes in the average shoreline and are the building blocks of the continental encroachment cycles. The time duration of the major transgressive regressive facies cycles typically range from 3 My to 50 My. They are defined as second order. These cycles are believed to be the result of changes in the rate of regional tectonic subsidence and / or changes in the rate of global tectono-eustacy. Tectono-eustacy changes are believed to be caused by major changes in the rates of sea-floor spreading, which cause the size of the ocean basin change. The second order transgressive regressive facies cycles that are caused by tectono-eustatic are shown as variations on the long term eustacy curve of the Haq et al. (1987). Sequence cycles are identified on the basis of changes in shelfal accommodation and are the building blocks of the major transgressive regressive facies cycles. They are composed of lowstand, transgressive and highstand systems tracts. These cycles are typically third order (0.5-3 My), but may be higher order during particular ages or certain phases of the third order sequence cycle. Third order sequence cycles are shown as the short term eustasy curve on the Haq et al. (1987) chart. (iv) Parasequence cycles are shallowing upward intervals bounded by surfaces of abrupt deepening of their correlative surfaces within the non marine environment. They may be periodic or episodic. Periodic parasequences are believed to be caused by Milankovitch orbital cycles and episodic parasequences by autocyclic or local tectonic processes. These cycles range from from fourth to sixth order (0.01-0.5 My). Parasequences are the building blocks of the systems tracts. The paper describes this new classification with special emphasis on the first order cycle type. The similarity of continental encroachment cycles in various areas of the world is illustrated by tentative geological interpretation of regional seismic lines.

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Stratigraphic Cycles and Major Marine Source Rocks

Bernard C. Duval, Carlos Cramez and Peter R. Vail

The following short-courses are available in UFP Repositório Institucional (Browsing by Author......... Cramez Carlos) :

Glossary of Salt Tectonics ;

Basic Principles in Tectonics ;

Bassins Sédimentaires et Systèmes Pétroliers ;

Salt Tectonics ;

Seismic Interpretation ;

Systemic Stratigraphy Seminar ;

Foredeep & Fold Belts ;

Volume Problems ;

Hydrodynamism ;

Turbidite Systems ;

Sequence Stratigraphy;

Rocky Mountains ;

Offshores Profonds ;

Probabilistic Reserve Assessment.