Editing A sequence-stratigraphy scheme of the Late Carboniferous, southern North Sea, Anglo-Dutch sector

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Third-order sequence cycles are normally of the order of duration of 0.5–3.0 Ma (Vail & Wornardt 1991). The systems tracts defined in this paper were deposited during a similar time period of 0.5–2.0 Ma. Based on the timescale of Harland et al. (1982), the deposition of the tracts has an approximate average duration of 1.5 Ma; the timescale of Lippolt et al. (1984) suggests a duration of around 1.0 Ma or less.
 
Third-order sequence cycles are normally of the order of duration of 0.5–3.0 Ma (Vail & Wornardt 1991). The systems tracts defined in this paper were deposited during a similar time period of 0.5–2.0 Ma. Based on the timescale of Harland et al. (1982), the deposition of the tracts has an approximate average duration of 1.5 Ma; the timescale of Lippolt et al. (1984) suggests a duration of around 1.0 Ma or less.
  
The great lateral persistence of dark shale marine bands in the Namurian containing thick-walled goniatites has been related to slow sedimentation during allocyclical sea-level rise (Read & Forsyth 1989, Read 1991). These sea-level changes are glacioeustatically controlled and are of high frequency and magnitude during a period of global “ice-house” climates, controlled by Milankovitch orbital parameters (Ramsbottom 1979, Leeder 1988, Elliot 1993). Heckel (1986, 1990) has demonstrated the same control on limestone–shale cycles of the Westphalian D to Stephanian B of central North America, and identified Pennsylvanian minor cycle periods that conform with the Milankovitch insulation theory controlling the Pleistocene ice ages. The longer of the major Pennsylvanian eccentricity cycles is about 400 000 years, which very broadly conforms to system-tract duration identified in this paper.
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The great lateral persistence of dark shale marine bands in the Namurian containing thick-walled goniatites has been related to slow sedimentation during allocyclical sea-level rise (Read & Forsyth 1989, Read 1991). These sea-level changes are glacioeustatically controlled and are of high frequency and magnitude during a period of global “ice-house” climates, controlled by Milankovitch orbital parameters (Ramsbottom 1979, Leeder 1988, Elliot 1993). Heckel (1986, 1990) has demonstrated the same control on limestone–shale cycles of the Westphalian D to Stephanian B of central North America, and identified Pennsylvanian minor cycle periods that conform with the Milankovitch insulation theory controlling the Pleistocene ice ages. The longer of the major Pennsylvanian eccentricity cycles is about 400000 years, which very broadly conforms to system-tract duration identified in this paper.
  
 
== 7. Macrofaunal biozones ==
 
== 7. Macrofaunal biozones ==

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