Morphosedimentary, Structural and Benthic Characterization of Carbonate Mound Fields on the Upper Continental Slope of the Northern Alboran Sea (Western Mediterranean)

24 pages, 5 figures, 2 tables, 1 appendix.-- Data Availability Statement: Datasets are stored in the database of the Instituto Español de Oceanografía (IEO) for the MONCARAL and RIGEL projects, some of which is available at the IEO marine geospatial information viewers and services: http://www.ieo.es/en/ideo (accessed on 15 December 2021)

Carbonate mounds clustering in three fields were characterized on the upper continental slope of the northern Alboran Sea by means of a detailed analysis of the morphosedimentary and structural features using high-resolution bathymetry and parametric profiles. The contemporary and past benthic and demersal species were studied using ROV underwater imagery and some samples. A total of 325 mounds, with heights between 1 and 18 m, and 204 buried mounds were detected between 155 to 401 m water depth. Transparent facies characterize the mounds, which root on at least six erosive surfaces, indicating different growth stages. At present, these mounds are covered with soft sediments and typical bathyal sedimentary habitat-forming species, such as sea-pens, cerianthids and sabellid polychaetes. Nevertheless, remains of colonial scleractinians, rhodoliths and bivalves were detected and their role as potential mound-forming species is discussed. We hypothesized that the formation of these mounds could be related to favorable climatic conditions for cold-water corals, possibly during the late Pleistocene. The occurrence on top of some mounds of abundant rhodoliths suggests that some mounds were in the photic zone during minimum sea level and boreal guest fauna (e.g., Modiolus modiolus), which declined in the western Mediterranean after the Termination 1a of the Last Glacial (Late Pleistocene)

This work is a contribution from “Contraste de la actividad geológica entre el sector este y oeste del mar de Alborán y cordilleras adyacentes”: AGORA (P18-RT-3275 (Junta de Andalucía), “Estudio y caracterización de montículos carbonatados en el Mar de Alborán”: MONCARAL (IEO) funded projects as well to a contribution of the ESMARES 2 (MITERD and Instituto Español de Oceanografía) project for improving the knowledge on the circalitoral and bathyal habitats of the northern Alboran Sea (Demarcación Estrecho-Alboran) (18ESMARES2-CIRCA). [...]. This work acknowledges to the `Severo Ochoa of Excellence’accreditation (CEX2019-000928-S)

Peer reviewed