The crustal structure of the western Amundsen Basin, Arctic Ocean, derived from seismic refraction/wide-angle reflection data

Carlos F. Castro, Thomas Funck, John R. Hopper

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Two geophysical expeditions (LOMROG II and III) were carried out in 2009 and 2012 to acquire seismic data in the western Amundsen Basin in the Arctic Ocean, a basin formed by ultraslow seafloor spreading at the Gakkel Ridge. Previous studies show alternating magmatic and amagmatic segments at the ridge but it is unclear if such segmentation persisted throughout the entire opening history of the basin. The seismic refraction data were used to develop P-wave velocity models down to the uppermost mantle using forward modelling of traveltimes. The coincident seismic reflection data were used to constrain the geometry of the sedimentary layers and for characterizing the acoustic basement. 2-D gravity modelling was used to determine the Moho depth in areas when data quality was insufficient to resolve a Moho reflection. The models distinguish three different basement types: oceanic crust with layers 2 and 3, oceanic crust that is lacking a layer 3 and exhumed and serpentinized mantle. The maximum observed crustal thickness is 6 km. Areas with thin crust (<3 km) may be underlain by partially serpentinized mantle. Where exhumed mantle is observed, a serpentinization front separates highly serpentinized mantle at the top from partially serpentinized mantle below. The presence of oceanic crust off-axis of the presently amagmatic sector of the Gakkel Ridge indicates that there is both a spatial and temporal variation of crustal accretion processes at the ridge.

Original languageEnglish
Pages (from-to)322-348
Number of pages27
JournalGeophysical Journal International
Volume236
Issue number1
DOIs
Publication statusPublished - 1 Jan 2024

Keywords

  • Arctic region
  • Controlled source seismology
  • Crustal structure
  • Gravity anomalies and Earth structure
  • Mid-ocean ridge processes

Programme Area

  • Programme Area 3: Energy Resources

Fingerprint

Dive into the research topics of 'The crustal structure of the western Amundsen Basin, Arctic Ocean, derived from seismic refraction/wide-angle reflection data'. Together they form a unique fingerprint.

Cite this