Category:Sequence Stratigraphy of the Chalk Group
|CONIACIAN||M. coranguinum||WHITE CHALK SUBGROUP||SEAFORD CHALK FORMATION||Coniacian 8|
|M. cortestudinarium||LEWES NODULAR CHALK FORMATION|
|TURONIAN||S. plana||Turonian 4|
|NEW PIT CHALK FORMATION|
|Mytiloides spp.||HOLYWELL NODULAR CHALK FORMATION|
|Cenomanian 6/Turonian 1|
|C. guerangeri||GREY CHALK SUBGROUP||ZIG ZAG CHALK FORMATION||Cenomanian 5|
|C. inerme||WEST MELBURY MARLY CHALK FORMATION|
|M. dixoni||Cenomanian 3|
Sequence stratigraphy seeks to subdivide rock successions into genetically related packages of sediment based on major changes in relative sea-level (Van Wagoner et al., 1988). The fundamental building block of sequence stratigraphy is the 'sequence', which when preserved intact, records a complete cycle of marine deposition, from an initial fall in relative sea level, through transgression and maximum flooding of the basin, culminating in a sea level highstand. The different stages in this cycle are called 'systems tracts', of which lowstand, trangressive and highstand are recognised (Van Wagoner et al., 1988). The Exxon Model emphasises the importance of the sequence boundary, generated during a relative sea level fall, whereas the Galloway model (Genetic Sequence Stratigraphy) places the emphasis on the maximum flooding surface (Galloway, 1989). In basin marginal areas, or where tectonic influences are pronounced, not all the elements in this cycle of relative sea level change are necessarily preserved in the rock record.
Sequence stratigraphy provides another useful means of correlating rock successions, and is a useful framework for understanding how and why different facies types or sedimentary packages occur in different basin settings, and to this end, it has the potential to be a powerful predictive tool in stratigraphical analysis. Although initially applied to siliciclastic successions, there is increasing realisation that it can also be applied to carbonate facies. Recently, several papers have attempted to identify sequences in the Cenomanian, Turonian and Coniacian of the Chalk Group of the UK (Gale, 1996; Robaszynski et al., 1998; Grant et al., 1999).
A detailed explanation of sequence stratigraphy is beyond the scope of this work, but Van Wagoner et al. (1988) provided a useful overview of key terms and concepts.
GALE, A S. 1996. Turonian correlation and sequence stratigraphy of the Chalk in southern England. In HESSELBO, S P & PARKINSON, D N (eds), Sequence Stratigraphy in British Geology, Geological Society Special Publication, 103, pp. 177-195.
GRANT, S F, COE, A L, ARMSTRONG, H A. 1999. Sequence stratigraphy of the Coniacian succession of the Anglo-Paris Basin. Geological Magazine, 136, 17-38.
ROBASZYNSKI, F, GALE, A, JUIGNET, P, AMÉDRO, F, HARDENBOL, J.1998. Sequence stratigraphy in the Upper Cretaceous series of the Anglo-Paris Basin: exemplified by the Cenomanian stage. Society of Economic Paleontologists and Mineralogists, Special Publication No. 60, 363-386.
VAN WAGONER, J C, POSAMENTIER, H W, MITCHUM, R M, VAIL, P R, SARG, J F, LOUTIT, T S & HARDENBOL, J. 1988. An overview of the fundamentals of sequence stratigraphy and key definitions. In WILGUS, C K, HASTINGS, B S, ROSS, C A, POSAMENTIER, H W, VAN WAGONER, J C & KENDALL, G St. C. (eds), Sea-level Changes: An Integrated Approach: Society of Economic Paleontologists and Mineralogists Special Publication, 42, 39-45.
GALLOWAY, W.E. 1989. Genetic Stratigraphic Sequences in Basin Analysis I: Architecture and Genesis of Flooding-Surface Bounded Depositional Units. American Association of Petroleum Geologists Bulletin, 73, 125-142.
Pages in category ‘Sequence Stratigraphy of the Chalk Group’
The following 17 pages are in this category, out of 17 total.