Utilization of Global Bathymetric Data to Characterize Large-Scale Bedforms in Atlantic Submarine Basins

Bathymetric data are integral to oceanographic research across a wide scope of scientific disciplines because these data provide unique marine geophysical information describing details of the seafloor. The Global Multi-Resolution Topography (GMRT) Synthesis provides access to high resolution multibeam data acquired throughout the global ocean, with a focus on data from the US Academic Research Fleet. GMRT Synthesis 100 m resolution products allow for the generation and analysis of detailed ocean floor geomorphology visualizations.

Knowledge of deep sea bedform morphology and stability can be used to understand deep water current flow and circulation patterns. Large-scale undulating bedforms were observed in three focus areas for which high-resolution multibeam data exist, including the Labrador Basin (depth: 3.2-3.6 km), the Atlantic Basin (depth: 4.7- 5.0 km), and the Argentine Basin (depth: 5.5-5.6 km). Study sites are located on the abyssal plain, 500 to 600 km off the continental shelf break. The observed bedforms vary in size and have average heights ranging from 120 m in the Argentine Basin to 40 m in the Labrador Basin, with wavelengths as great as 10 km. A unified understanding of the morphological classification, formation/development mechanisms, and dynamic migration of these bedforms does not exist at this time, nor have comparisons been made across these different environments.

This study explores the morphology of deep-water bedforms to better understand mechanisms of their formation. Cross-sectional profiles of sediment wave geometry and orientation are used to infer bottom current velocity and to predict potential bedform migration. Comparisons among sites as well as temporal variability within sites, using data collected from 1984 through 2015, are also considered. Where possible, bathymetric and backscatter intensity surfaces are used to consider variations in bedform sedimentology.

Global analysis of detailed seabed morphology relies heavily on the sharing of data and synthesis of datasets collected during multiple expeditions, often spanning decades of data acquisition. Data used for this study will be contributed to the Seabed 2030 Project through the Atlantic and Indian Ocean Regional Data Center.