Mass Failure Complex Morphometrics as an Indicator of Flow Rheology and Composition: A Comprehensive Study in the Gulf of Mexico

Abstract

Morphology of mass failure complexes (MFCs; also called mass-transport complexes) across a variety of tectonic settings reveal strong linkages between geometry, flow rheology, and nature of the failure materials. Understanding these relationships in the future may enable interpretation of pressure distribution, stability nature, and composition of ancient mass failures as well as prediction of post-emplacement turbidite top fills using MFCs’ morphologic character. To decipher and quantify such relationships, we employ a newly-released, high-resolution (1.4 billion, 40-by-40-feet-sized pixels) bathymetry dataset of the Gulf of Mexico (GOM) developed by the Bureau of Ocean Energy Management. We map and classify slope and basin floor MFCs across a number of varied tectonomorphic provinces in the GOM, including the carbonate-dominated Florida Escarpment, the sediment-dominated Mississippi Fairway, the compressionally-dominated Atwater Fold and Thrust Belt, the salt-thrust dominated Walker Ridge area, the canyon-dominated Bryant region, and the Rio Grande river delta-dominated western slope. We hypothesize that the variability of in situ sediment types and structures in each GOM province yields MFCs with variable morphology in part due to the hypothesized linkages between geometry, flow rheology, and failure sediment character. In addition to bathymetry data, this study utilizes seismic surveys, well logs, and sediment cores to test the quantitative relationships between MFCs’ morphometrics and their flow rheology and composition. Existing and newly developed tools in ArcGIS have been used to map and characterize MFCs' parameters that include center of mass, geometry, volume, post-emplacement accommodation, surface roughness, and roughness trends. We focus on these parameters because they are related to MFCs’ nature and significantly influence the pathways and architecture of post-emplacement turbidite units. We also relate our findings to current MFC databases to examine linkages between MFCs’ morphometrics and their occurrences as attached/detached events, confined/unconfined settings, and other contextual considerations. This study provides a better understanding of MFCs’ nature in variable settings. Statistical predictive models drawn from this analysis can be used to reduce exploration uncertainties in seals and reservoirs in both MFC deposits as well as in the post-emplacement top fill turbidites.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018