Examining Guyots in the Mid-Pacific Mountains



The Western Pacific is strewn with chains and clusters of seamounts, many of which are now flat-topped submarine seamounts, or guyots, with summit depths of about 1500 m. Many guyots are capped by shallow-water carbonate platform sediments overlying volcanic substrate. Guyot sediments can serve as “dip sticks” to monitor subsidence rates and relative changes in sea level for times when upward carbonate-platform growth occurred during tectonic subsidence of their foundations. Such sediments encode the timing and sense of sea-level rises and falls in their mineralogy, textures, and fossils. Guyot volcanic pedestals preserve, in their mineralogy and chemistry, clues to the nature of their parent mantle materials and the processes of melt extraction and differentiation.