--> Abstract: Skeletal Mound Growth Model Based from Examples from the Carboniferous and Middle Cretaceous, by Xavier Janson and Charles Kerans; #90078 (2008)

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Skeletal Mound Growth Model Based from Examples from the Carboniferous and Middle Cretaceous

Xavier Janson and Charles Kerans
Jackson School of Geosciences, University of Texas at Austin, Austin, TX

Many important buildup-forming organisms create mounds that lack rigid frameworks and as such are strongly modified by the hydrodynamic setting and accommodation. A range of hydrodyamically influenced buildup systems including Mississipian pelmatozoian mounds, Pennsylvanian crinoidal mud-mounds and phylloid algal buildups, and Cretaceous rudist mounds were used to develop a general model for the response of buildup size, shape,and internal fabric to position on the platform and position within a longer -term accommodation setting. Mound architecture depends on initial position along the depositional profile, the depth of the photic zone, and hydrodynamic energy. Mounds that grew in a proximal position under low accommodation settings between fair weather and storm wave base (FWWB, SWB) have smaller mound cores and are associated with large amounts of reworked debris. Mounds that grew in a more distal position have thicker mound cores and, depending on the depth of FWWB and SWB, these mounds display debris to mound-core ratios of 1:1 to 5:1. Further down dip, mound cores are well developed but lack significant mound-flank debris indicating growth below SWB. This general model was used to guide facies interpolation in 3D outcrop-based geocellular models.

 

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas