Sedimentologic and Geometric Criteria for Comparing Modern and Ancient Sandy Turbidite Elements
Deep water depositional systems are formed by a combination of turbidite elements, which can be recognized from modern and ancient settings using outcrop observations, seismic-reflection data, or well-log and core data. Elements of turbidite systems can be compared to derive general sedimentologic parameters only if physical scales, geometry, time frame for deposition, and linked turbidite elements are reasonably similar. If these parameters are not considered, turbidite-channel elements, a common reservoir target, can easily be confused with other “channellike” elements. In some deposits, one or more of the elements are represented by several distinct sub-elements, e.g., a succession of both lensoid and wedge-shaped lobe deposits can comprise the lobe-element area. The different lobe sub-elements develop in response to shifts in position of the channel mouth and changes in the sediment supply. An understanding of the dimensions, facies, and stratigraphic development of these modern and ancient turbidite elements can provide criteria for distinguishing turbidite elements. In addition, an improvement in our understanding of the geometric and sedimentologic characteristics of specific turbidite systems can eventually lead to better predictive depositional models.