South Arch volcanic field; newly identified young lava flows on the sea floor south of the Hawaiian Ridge
South Arch volcanic field; newly identified young lava flows on the sea floor south of the Hawaiian Ridge
Geology (Boulder) (July 1989) 17 (7): 611-614
- acoustical methods
- age
- arches
- basanite
- Central Pacific
- composition
- dredged samples
- East Pacific
- geophysical methods
- geophysical surveys
- GLORIA
- Hawaiian Ridge
- hot spots
- igneous rocks
- lava
- lava flows
- marine environment
- North Pacific
- Northeast Pacific
- observations
- ocean floors
- oceanography
- Pacific Ocean
- seamounts
- side-scanning methods
- sonar methods
- submarine environment
- surveys
- vents
- volcanic rocks
- volcanism
- volcanology
- South Arch volcanic field
Several young lava fields were imaged by GLORIA sidescan sonar along the Hawaiian Arch south of Hawaii. The largest, 35 by 50 km across, includes a central area characterized by high sonar backscatter and composed of several flow lobes radiating from a vent area. Reflection profiling and sea-floor photography indicate that the central lobes are flat sheet flowsbounded by pillowed margins; thin surface sediment and thin palagonite rinds on lava surfaces suggest ages of 1-10 ka. Vents are localized along the arch crest near bases of Cretaceous seamounts. Two dredged flows are basanite and alkalic basalt, broadly similar to rejuvenated-stage and some pre-shield alkalic lavas on the Hawaiian Ridge. Arch volcanism representsperipheral leakage of melt from the Hawaiian hot spot over much larger areas than previously recognized.
