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Rough versus smooth topography along oceanic hotspot tracks: Observations and scaling analysis
Author(s) -
OrellanaRovirosa Felipe,
Richards Mark
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl072008
Subject(s) - hotspot (geology) , lithosphere , magmatism , geology , volcano , seismology , lava , pacific plate , geophysics , subduction , tectonics
Some hotspot tracks are topographically smooth and broad (Nazca, Carnegie/Cocos/Galápagos, Walvis, Iceland), while others are rough and discontinuous (Easter/Sala y Gomez, Tristan‐Gough, Louisville, St. Helena, Hawaiian‐Emperor). Smooth topography occurs when the lithospheric age at emplacement is young, favoring intrusive magmatism, whereas rough topography is due to isolated volcanic edifices constructed on older/thicker lithosphere. The main controls on the balance of intrusive versus extrusive magmatism are expected to be the hotspot swell volume flux Q s , plate hotspot relative speed v , and lithospheric elastic thickness T e , which can be combined as a dimensionless parameter R = ( Q s / v ) 1/2 / T e , which represents the ratio of plume heat to the lithospheric heat capacity. Observational constraints show that, except for the Ninetyeast Ridge, R is a good predictor of topographic character: for R < 1.5 hotspot tracks are topographically rough and dominated by volcanic edifices, whereas for R > 3 they are smooth and dominated by intrusion.