Alternative models of guyot formation on mid-Cretaceous Pacific seafloor
Abstract
Ongoing seafloor mapping programs continue to improve our view of seafloor morphology and understanding of related geologic and oceanographic process. One such example is the origin and evolution of seamounts, and in particular, flat-topped seamounts known as guyots. Conventional models of guyot formation include seamounts, which have been exposed to subaerial erosion and/or carbonate reef formation, and then submerged due to subsidence of the seafloor. More recent explanations do not require subaerial exposure, but instead invoke a range of volcanic processes including over-topping calderas, ring dikes, or cone sheets.
A recent expedition aboard the E/V Nautilus (NA110) mapped several seamounts in the Pacific Remote Islands National Marine Monument with high-resolution swath bathymetry and ROV observations. We surveyed a range of seamount features including a landslide scarp, several late-stage volcanic cones along the Line Islands plateau, an isolated seamount adjacent to the Line Islands plateau, and several other isolated seamounts near Jarvis Island, including Jarvis Island. Some of the more intriguing geologic observations include the extensive lobate flows and sheet flows along the seamount flanks and the possible presence of lava tubes at the summits of some of the seamounts. Somewhat surprising was the lack of extensive carbonate deposits on the flanks of the seamounts, except for the upper 800 m of Jarvis Island and relatively thin layers on Kingman Ridge. These combined observations suggest several possible alternate origins for the various seamounts we surveyed. We combine our mapping and sampling observations with tectonic reconstructions and seafloor subsidence models to explore the possible origin and history of these seamounts. We further extend these observations to provide a more global view of the potential spatial and temporal distribution of various forms of seamounts and guyots.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMOS11A..06P
- Keywords:
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- 3045 Seafloor morphology;
- geology;
- and geophysics;
- MARINE GEOLOGY AND GEOPHYSICS;
- 4894 Instruments;
- sensors;
- and techniques;
- OCEANOGRAPHY: BIOLOGICAL;
- 4260 Ocean data assimilation and reanalysis;
- OCEANOGRAPHY: GENERAL;
- 4262 Ocean observing systems;
- OCEANOGRAPHY: GENERAL