Submarine volcanic morphology of the western Galápagos based on EM300 bathymetry and MR1 side-scan sonar

• Published in: Geochemistry, geophysics, geosystems : G3 Vol. 8; no. 3; pp. Q03010 - n/a
• Main Authors: Glass, Jennifer B., Fornari, Daniel J., Hall, Hillary F., Cougan, Allison A., Berkenbosch, Heidi A., Holmes, Mark L., White, Scott M., De La Torre, Giorgio
• Format: Journal Article
• Language: English
• Published: American Geophysical Union 01.03.2007; Blackwell Publishing Ltd
• Subjects: Cones; Construction; deep lava flows; EM300 multibeam bathymetry; Flanks; Galápagos Islands; Islands; Lava; Marine Geology and Geophysics; Marine magnetics and paleomagnetics; Morphology; MR1 side-scan sonar; Oceanic hotspots and intraplate volcanism; Sonar; Subaqueous volcanism; submarine volcanic cones; submarine volcanic rift zones; Submarines; Volcanology; ASE, Atlantic, Canary Is; Ecuador, Galapagos Is; submarine volcanic rift zones; EM300 multibeam bathymetry; MR1 side-scan sonar; submarine volcanic cones; deep lava flows; Galápagos Islands
• ISSN: 1525-2027; 1525-2027
• DOI: 10.1029/2006GC001464

A compilation of high‐resolution EM300 multibeam bathymetric and existing MR1 side‐scan sonar data was used to investigate the volcanic morphology of the flanks of the western Galápagos Islands. The data portray an assortment of constructional volcanic features on the shallow to deep submarine flanks of Fernandina, Isabela, and Santiago Islands, including rift zones and groups of cones that are considered to be the primary elements in constructing the archipelagic apron. Ten submarine rift zones were mapped, ranging in length from 5 to 20 km, comparable in length to western Canary Island rift zones but significantly shorter than Hawaiian submarine rift zones. A detailed analysis of the northwestern Fernandina submarine rift, including calculated magnetization from a surface‐towed magnetic study, suggests that the most recent volcanism has focused at the shallow end of the rift. Small submarine volcanic cones with various morphologies (e.g., pointed, cratered, and occasionally breached) are common in the submarine western Galápagos both on rift zones and on the island flanks where no rifts are present. At depths greater than ∼3000 m, large lava flow fields in regions of low bathymetric relief have been previously identified as a common seafloor feature in the western Galápagos by Geist et al. (2006); however, their source(s) remained enigmatic. The new EM300 data show that a number of the deep lava flows originate from small cones along the mid‐lower portion of the NW submarine rift of Fernandina, suggesting that the deep flows owe their origin, at least in part, to submarine rift zone volcanism.