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

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The nine marine bands recorded by Calver (1968) in the overlying strata of the East Midlands and elsewhere, up to and including the Burton Joyce Marine Band, may be flooding surfaces of fourth-order sequences or parasequence boundaries within a third-order composite sequence. Such common flooding surfaces might be expected within an HST characterized by continually rising sea level, although at a diminishing rate of rise to that represented at the MFS. In upward progression, the marine bands are the Holbrook, Second Smalley, First Smalley, Alton, Parkhouse, Forty Yard, Norton and Upper Band.
 
The nine marine bands recorded by Calver (1968) in the overlying strata of the East Midlands and elsewhere, up to and including the Burton Joyce Marine Band, may be flooding surfaces of fourth-order sequences or parasequence boundaries within a third-order composite sequence. Such common flooding surfaces might be expected within an HST characterized by continually rising sea level, although at a diminishing rate of rise to that represented at the MFS. In upward progression, the marine bands are the Holbrook, Second Smalley, First Smalley, Alton, Parkhouse, Forty Yard, Norton and Upper Band.
  
The ''A. lenisulcata ''zone is generally argillaceous in the UK onshore area, although in the East Midlands the Crawshaw Sandstone is locally well developed, forming the main reservoir rocks of several small oil fields. Flint et al. (1995) have demonstrated significant incision by this sandstone, which in the Bothamsall-5 well has removed the Rough Rock and underlying strata to the Cancellatum Marine Band. However, when examined regionally, it is apparent that the Crawshaw Sandstone is discontinuous. Intermittent development of thick (10 m or more) high-sinuosity sandstones of Early Langsettian age is also seen in offshore wells ([[:File:YGS_CHR_06_ASEQ_FIG_06A.jpg|Figure 6A]]). Such sandstone bodies may represent more proximal (landward) clastic-dominated parasequences.
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The ''A. lenisulcata ''zone is generally argillaceous in the UK onshore area, although in the East Midlands the Crawshaw Sandstone is locally well developed, forming the main reservoir rocks of several small oil fields. Flint et al. (1995) have demonstrated significant incision by this sandstone, which in the Bothamsall-5 well has removed the Rough Rock and underlying strata to the Cancellatum Marine Band. However, when examined regionally, it is apparent that the Crawshaw Sandstone is discontinuous. Intermittent development of thick (10m or more) high-sinuosity sandstones of Early Langsettian age is also seen in offshore wells ([[:File:YGS_CHR_06_ASEQ_FIG_06A.jpg|Figure 6A]]). Such sandstone bodies may represent more proximal (landward) clastic-dominated parasequences.
  
 
The acmes of arborescent lycopod spores (lycospores) of ''Lepidodendron''/''Lepidophloios ''forests in this HST is in keeping with a time of marine transgression and the formation of major areas of peat swamp. Other taxa that show temporary acmes within the zone include ''Cingulizonates loricatus, Radiizonates difformis, Camptotriletes bucculentus ''and ''Grumosisporites varioreticulatus. ''Influxes of inertinitic kerogen may be associated with structural changes in the Coal Measures flora and substrate associated with many intermittent and short-lived flooding events. Towards the top of the ''A. lenisulcata ''zone, pale amorphous organic matter appears, together with the persistent up-hole appearance of ''Laevigatosporites ''spp.
 
The acmes of arborescent lycopod spores (lycospores) of ''Lepidodendron''/''Lepidophloios ''forests in this HST is in keeping with a time of marine transgression and the formation of major areas of peat swamp. Other taxa that show temporary acmes within the zone include ''Cingulizonates loricatus, Radiizonates difformis, Camptotriletes bucculentus ''and ''Grumosisporites varioreticulatus. ''Influxes of inertinitic kerogen may be associated with structural changes in the Coal Measures flora and substrate associated with many intermittent and short-lived flooding events. Towards the top of the ''A. lenisulcata ''zone, pale amorphous organic matter appears, together with the persistent up-hole appearance of ''Laevigatosporites ''spp.

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