Changes

==Biofacies mixing==

==Biofacies mixing==

The downslope transport of shallow-water faunas by sediment gravity-flow processes may result in the mixing of biofacies assemblages from different environments.<ref name=ch04r119>Woodbury, H., O., Murray, I., B., Pickford, P., J., Akers, W., H., 1973, Pliocene and Pleistocene depocenters, outer continental shelf, Louisiana and Texas: AAPG Bulletin, vol. 57, p. 2428–2439.</ref> The further mixing of stratigraphically separate assemblages by rotary drilling complicates the identification of mixed assemblages. Such problems can be overcome in three ways:

The downslope transport of shallow-water faunas by sediment gravity-flow processes may result in the mixing of biofacies assemblages from different environments.<ref name=ch04r119>Woodbury, H., O., Murray, I., B., Pickford, P., J., Akers, W., H., 1973, [http://archives.datapages.com/data/bulletns/1971-73/data/pg/0057/0012/2400/2428.htm Pliocene and Pleistocene depocenters, outer continental shelf, Louisiana and Texas]: AAPG Bulletin, vol. 57, p. 2428–2439.</ref> The further mixing of stratigraphically separate assemblages by rotary drilling complicates the identification of mixed assemblages. Such problems can be overcome in three ways:

* Careful sample analysis, specifically looking for mixed assemblages

* Careful sample analysis, specifically looking for mixed assemblages

* Evaluation of the mapped pattern of age-equivalent interpretations from a large number of wells

* Evaluation of the mapped pattern of age-equivalent interpretations from a large number of wells

Armentrout<ref name=ch04r7 /> <ref name=ch04r9 />) carefully reexamines rapid changes of biofacies and patterns of rapid biofacies variations within age-equivalent intervals between wells. Once these local patterns were reevaluated and accepted as reliable, the interpretations were mapped for each depositional sequence. Figure 4-29 is the results of this analysis and further supports the biofacies models of Figure 4-30.

Armentrout<ref name=ch04r7 /> <ref name=ch04r9 /> carefully reexamines rapid changes of biofacies and patterns of rapid biofacies variations within age-equivalent intervals between wells. Once these local patterns were reevaluated and accepted as reliable, the interpretations were mapped for each depositional sequence. Figure 4-29 is the results of this analysis and further supports the biofacies models of Figure 4-30.

==See also==

==See also==