Sequence stratigraphy in active extensional basins: implications for the interpretation of ancient basin-fills

• Published in: Marine and petroleum geology Vol. 11; no. 6; pp. 642 - 658
• Main Authors: Gawthorpe, Robert L., Fraser, Alastair J., Collier, Richard E.Li
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.12.1994; Elsevier Science
• Subjects: central Greece; Earth sciences; Earth, ocean, space; Exact sciences and technology; extensional basins; Marine; sequence stratigraphy; Stratigraphy; Tectonics. Structural geology. Plate tectonics; Greece; Europe; extensional basins; sequence stratigraphy; central Greece; glaciomarine environment; eustacy; Neogene; Quaternary; Tertiary; structural controls; normal faults; Pliocene; extension tectonics; bedrock; subsidence; fault zones; segmentation; drainage; sea level
• ISSN: 0264-8172; 1873-4073
• DOI: 10.1016/0264-8172(94)90021-3

Systematic variations in sequences, their component units and their stacking patterns exist within rift basins. These variations can be related to displacement gradients associated with the large-scale (12–50 km) segmentation of normal fault zones, which control accommodation, sediment supply and basin physiography. Sediment supply is also strongly influenced by the nature of pre-rift drainage networks and variations in bedrock lithology. High rates of hangingwall subsidence close to the centre of normal fault segments may cancel out the effects of glacio-eustatic sea-level fall, so that accommodation development is normally characterized by the continual addition of new space. The resulting sequences lack type 1 sequence boundaries and lowstand systems tracts, and stack into aggradational sequence sets. The adjacent footwall is subject to uplift, which may lead to subaerial exposure and incision, generating a composite type 1 sequence boundary. Away from the fault zone and near segment boundaries, slip rates are much lower and hence relative sea-level change is dominated by eustasy. Here, falls in relative sea level are important, resulting in type 1 sequences. Sequence stacking patterns reflect not only eustasy and local fault-controlled subsidence, but also the interaction of these with adjacent uplifting footwalls and/or regional uplift. Tectonic influence on sequence development will be more pronounced during greenhouse times than icehouse times.