--> Abstract: Calibrating Core-Scale Observations in Remobilized Turbidites Using Outcrop Analogues, by A. Del Pino Sanchez, R.W.H. Butler, W.D. McCaffrey, and P.D.W. Haughton; #90039 (2005)

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Calibrating Core-Scale Observations in Remobilized Turbidites Using Outcrop Analogues

A. Del Pino Sanchez1, R.W.H. Butler1, W.D. McCaffrey1, and P.D.W. Haughton2
1 University of Leeds, Leeds, United Kingdom
2 University College Dublin, Dublin, Ireland

Remobilised turbidite successions encountered in core commonly display bewildering complexity in facies variations (e.g., massive facies juxtaposed against slurry facies). Understanding the lateral extent of these relationships is often critical when building reservoir models. Here we present data from an outcrop analogue that illustrate lateral facies relationships within remobilised turbidites.

A standard problem when investigating the products of sediment remobilisation is distinguishing between deformation due to shear coupling with an over-riding flow, down-slope mass-wasting processes and tectonic deformation. Identification of growth strata and/or bed-top erosive features is key (as these define the depth below palaeo-seabed at which the deformation occurred together with a qualitative appreciation of deformation rate - creep vs. catastrophic failure). If possible independent determinations of palaeo-flow and palaeo-slope orientations should be measured. These data must be integrated with the analysis of soft-sediment deformation.

These workflows can be challenging when analysing remobilisation in core. Outcrop allows a better understanding of microfacies characteristics by enabling study of lateral variation of a bed package not possible in width-limited core. Here we present part of our results from the outcrop studies in the Champsaur sector of the Tertiary Alpine Foreland Basin system of SE France. Palaeoflow context is provided by axial sediment transport with ripple deflection off the basin margins. Remobilisation direction is down the lateral palaeoslope. Thus kinematic data obtained from remobilised fabrics allows us to deduce paleoslope orientation and evolution. These are important because they provide consistent orientation information which can be linked to larger scale remobilisation.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005