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Quantifying Periodic Variations in Hotspot Melt Production
Author(s) -
Morrow T. A.,
Mittelstaedt E. L.
Publication year - 2021
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1029/2021jb021726
Subject(s) - hotspot (geology) , geology , mantle (geology) , plume , mantle plume , seafloor spreading , geophysics , volcano , mantle convection , crust , igneous rock , petrology , subduction , seismology , geochemistry , lithosphere , tectonics , physics , thermodynamics
Abstract Fluctuations in estimated mantle plume melt production rates suggest complex dynamics in the upper mantle including changes in plume upwelling, compositional heterogeneity within plume stems, entrainment of anomalous mantle, or other processes. Despite the implications for mantle dynamics, differences between previous studies including the methods, study areas, and types of melt volumes estimated, limit inter‐hotspot comparisons and assessment of global variability. Here, we use a consistent methodology to calculate igneous melt production through time across a suite of 12 hotspot chains located in the Pacific, Indian, and Atlantic Ocean basins. Using global data sets of topography, gravity, sediment cover, and seafloor age along with spectral methods for calculating elastic plate flexure and gravity anomalies, we estimate the total volume of igneous material at each hotspot in three components: (a) volcanic edifices, (b) flexural infill, and (c) intrusions (underplating) within the upper mantle and lower crust. Results indicate time‐averaged melt production rates across all studied hotspots range from 3.44 m 3 s −1 (Cobb) to 14.75 m 3 s −1 (Kerguelen), with underplating making up the largest component. Through time, melt production rates vary from 0.1 to 2.5 times average values with statistically significant periodic fluctuations of 1.1–71.5 Myr. Spectral analysis of estimated melt volumes shows total melt production varies periodically at all 12 hotspots. Excepting Galápagos, the studied hotspots exhibit multiple periodicities of melt production variability, implying complex dynamic, thermal, and/or chemical processes within the plume conduit. Moreover, we find several groups of hotspots exhibiting similar periods of melt production variability.