1995/12/01 by Douglas D. Bergersen · 3 citations
Earth and Planetary Sciences · #Geological and Geochemical Analysis #High-pressure geophysics and materials #earthquake and tectonic studies #Geology #Hotspot (geology) #Cretaceous #Paleontology #Seismology
paper · pdf · doi:10.2973/odp.proc.sr.144.018.1995
openalex publication_date 1995/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04
Pacific Plate rotations show that the Marshall Islands were located near French Polynesia during the time of their construction in the Cretaceous. Edifices within the various island chains fail to show a simple linear age progression in the direction of plate motion. Mid-Cretaceous fossil ages and Late Cretaceous radiometric ages suggest that two episodes of volcanism and uplift have occurred across this region. The Cretaceous tracks of the Cook-Austral and Society island hotspots superimposed on oblique Mercator projections of the Marshall Islands topography show that (1) the Ralik Chain formed during the Late Cretaceous but not over any of the present French Polynesian hotspots, (2) the northern Marshall Islands crossed the Macdonald hotspot during the stage from 74 to 100 Ma, (3) the Ratak Chain formed over either the Rurutu or Society hotspots, and (4) the Anewetak-Ujlan volcanic cluster correlates with the Rarotonga hotspot and a change in plate motion. Misfits between the model tracks for the French Polynesian hotspots and the observed topography and sparse age information for the Marshall Islands may result from either (1) more Cretaceous hotspots in French Polynesia than are currently observed, (2) weaker mantle plumes and consequently a shorter duration of volcanism in the French Polynesia area, or (3) the slow movement of existing hotspots relative to other Pacific hotspots.