A two-part seabed geomorphology classification scheme. Part 2: Geomorphology classification framework and glossary - Version 1.0.

Abstract

Maps of seabed geomorphology provide foundational information for a broad range of marine applications. These maps rely on bathymetry data from which geomorphic units can be identified, supported by knowledge of the geological setting and/or processes. Bathymetry data are becoming more widely available thanks to several key global initiatives, notably the Seabed 2030 project, United Nations Sustainable Development Goals and UN Ocean Decade, together with global recognition of the value of the Blue Economy. To contribute most effectively to supporting these global efforts, geomorphic characterisation of the seabed requires standardised multi-scalar and interjurisdictional approaches that can be applied locally, regionally and internationally based on the best available data. An ongoing collaboration between geoscience agencies in the United Kingdom (British Geological Survey), Norway (Geological Survey of Norway), Ireland (Geological Survey Ireland and University College Cork) and Australia (Geoscience Australia) has focused on developing a new standardised approach to meet this need. Dove et al., (2016) initially described a two-part approach for mapping the geomorphology of the seabed. Part 1 is intended to guide the mapping of the seabed surface shape (Morphology), and Part 2 is intended to classify these shapes with their geomorphic interpretation.  Part 1 (Morphology: Dove et al., 2020) is available as an open access glossary. It contains an illustrated list of terms and definitions that primarily draw on the well-established International Hydrographic Organization standard. Morphology maps can be created by applying Part 1 Morphological terms to bathymetry data.  Part 2 (Geomorphology) is described in this report. Geomorphic units are structured within geomorphic Settings and Processes and (consistent with Part 1) these terms are primarily sourced from established literature. The application of this second mapping step requires further seabed data and/or contextual information and expert judgement, and is intended to constrain the uncertainty that is inherent to subsurface interpretation to this step. This document describes and illustrates the structuring of established geomorphic terminology into eleven geomorphic Settings and related Processes that drive the formation, modification and preservation of geomorphic units along the coast and at the seabed. Unit terms and Settings/Processes have been selected and structured to balance established terminology with the need for consistency between the broad range of included geomorphologies. This document also presents a glossary defining 406 units that are structured within the Part 2 Geomorphology classification system, and lists the applied insights that can be gained by mapping each unit. This two-part approach is not intended to replace discipline-specific classification systems (e.g. ecological, geological). Rather, it is intended to support consistent classification of seabed geomorphology for uptake and ingestion by multiple discipline-specific end-users and their classification systems. Translations between this Part 2 Geomorphology approach and several other key classifications are described herein.