Bathymetry and changes on seafloor topography of the southern Reykjanes Ridge (2013 multibeam survey — SOEST/Hí)

摘要

The Reykjanes Ridge, extending from Iceland to approximately 55°N, is the northernmost part of the Mid-Atlantic ridge. It segregates the North American and Eurasian tectonic plates, and therefore has typically very high volcanic activity. It is an anomalous mid-ocean ridge, with an axis-parallel morphology converging to its axis on approximately 58N, without any transform boundaries. Such places are widely unexplored and might reserve important mineral resources. In this work, we present a new bathymetric map of a selected area in the southernmost part of the ridge, between 57.5° and 58.5°N. The data used for the maps result from multibeam echosounder surveys that happened in 2013, 1990, 1993 and 1994, on board of the research vessels Marcus G. Langseth, Maurice Ewing and Charles Darwin. From the newest dataset, normal faults were mapped and the faulting direction was derived at two different provinces: West and East. Additionally, the directions of the ridges on the central valley (graben) were also analyzed. Data from the first bathymetric survey ever performed at the Ridge, funded by the British Initiative BRIDGE was used in order to perform change detection analysis. This analysis aimed the identification of topographic changes that would have been caused by volcanic eruptions. The original data comes from four different research cruises and it was heavily processed and further integrated by the authors, whom provided us with the resulting raster image. Only a part of the raw data, acquired by the American Vessel M. Ewing, was obtained from NOAA in. xyz format and processed on ArcGIS for the aims of this work. Image differencing was then performed, to detect changes that might have happened within a time span of up to 23 years. The resulting image shows the intensity and value of change, where the negative values represent an increase in depth, and positive values represent a decrease in depth, or in other words, a decrease or increase in seafloor topographic elevation.