mantle plume hypothesis

mantle plume hypothesis
Name	Mantle plume hypothesis
Field	Geology, Geophysics, Petrology
Proposer	W. Jason Morgan, Georges Poincaré
Year	1971

mantle plume hypothesis

The mantle plume hypothesis proposes that narrow, buoyant upwellings of hot rock rise from deep within the Earth to produce localized volcanic and tectonic phenomena. Originating in the late 20th century, the idea links deep-seated thermal anomalies to surface expressions such as Hawaii, Iceland, and Yellowstone National Park and has shaped debates involving W. Jason Morgan, André Cailleux, and subsequent generations of geophysicists. Proponents draw on data from seismology, geochemistry, geodesy, and petrology while critics cite plate-driven processes and alternative explanations championed by groups at institutions like Scripps Institution of Oceanography and Utrecht University.

Overview and history

The concept of mantle plumes was popularized by W. Jason Morgan in 1971 to explain intraplate volcanism not readily accounted for by plate boundaries, linking events such as the formation of the Hawaii–Emperor seamount chain, Icelandic flood basalts, and the Deccan Traps to mantle upwelling. Early antecedents include dynamic mantle convection ideas explored at University of Cambridge and observations from volcanic provinces like Afro-Arabian Rift System and Seychelles Bank. Debates intensified with seismic tomographic images from projects at US Geological Survey, Lamont–Doherty Earth Observatory, and Institut de Physique du Globe de Paris that variously supported or challenged deep-rooted plume structure. Key historical controversies involved interpretations by researchers associated with University of Oxford, Caltech, and ETH Zurich, and high-profile case studies such as Yellowstone National Park kept the hypothesis in public and scientific view.

Theoretical framework

The theoretical framework invokes buoyant thermal instabilities arising near the core–mantle boundary or within the lower mantle that evolve into narrow, cylindrical upwellings and broader plume heads. Models developed at Princeton University, Massachusetts Institute of Technology, and Paris-Sud University combine fluid dynamics, heat transfer, and phase transitions in silicate minerals constrained by experiments at Oak Ridge National Laboratory and Lawrence Berkeley National Laboratory. Proposed mechanisms involve interaction with the D″ layer and chemical heterogeneities such as large low-shear-velocity provinces (LLSVPs) beneath Africa and Pacific Ocean. Numerical simulations from groups at University of California, Santa Cruz and Seismological Society of America explore plume ascent rates, entrainment, and lithosphere–asthenosphere coupling. The framework predicts features like anomalous surface heat flow, basaltic composition trends, and long-lived volcanic tracks traced relative to plates such as the Pacific Plate and North American Plate.

Observational evidence

Supportive observations derive from seismic tomography studies by teams at Scripps Institution of Oceanography, ETH Zurich, and Stanford University revealing low-velocity zones interpreted as hot upwellings, alongside geochemical signatures measured at Smithsonian Institution and Max Planck Institute for Chemistry showing isotopic systems (e.g., helium, lead, strontium) consistent with deep mantle sources. Geodetic datasets from NASA and European Space Agency detect uplift patterns associated with long-lived volcanic centers like Iceland and Hawaii. Petrological experiments at Carnegie Institution for Science and field mapping in provinces such as the Siberian Traps and Columbia River Basalt Group yield stratigraphic sequences compatible with plume head–tail dynamics. Chronological constraints from radiometric labs at USGS and Australian National University link age-progressive volcanic chains to relative plate motions around features like the Galápagos Islands and Society Islands.

Alternative models and criticisms

Critics from University College London, University of Cambridge, and University of Tokyo propose plate-driven explanations that attribute intraplate volcanism to lithospheric extension, small-scale convection, edge-driven upwelling, or fertile heterogeneities in the upper mantle. Studies by researchers at University of Oregon and University of Leeds emphasize the role of fracture zones, transform faults, and continental rifting—invoking case studies such as the Azores and Canary Islands—to explain magmatism without deep plumes. Meta-analyses in journals associated with American Geophysical Union and Geological Society of America underscore ambiguities in seismic resolution, non-unique geochemical interpretations, and the patchy distribution of predicted heat-flow anomalies. Prominent critiques also emerged from teams at University of Hawaii and Imperial College London arguing that some plume-predicted features are absent or transient.

Implications for mantle dynamics and surface geology

If plume dynamics are widespread, they imply significant vertical material and heat transfer between the core–mantle boundary and lithosphere, affecting global mantle convection patterns studied at University of Edinburgh and influencing the formation of large igneous provinces such as the Karoo-Ferrar event. Plumes modify lithospheric stress fields, potentially interacting with plate boundaries like the Mid-Atlantic Ridge and influencing continental breakup scenarios exemplified by East African Rift. They bear on planetary comparisons drawn with Mars and Venus by teams at Jet Propulsion Laboratory and European Southern Observatory, where plume-like processes may drive volcanism absent plate tectonics. Understanding plume behavior informs hazard assessment near hotspots monitored by United States Geological Survey and informs resource exploration linked to volcanic provinces studied by British Geological Survey.

Key case studies

Key case studies include the Hawaii–Emperor seamount chain where age-progressive volcanism and bathymetric tracks match plume-ridge interactions mapped by NOAA and researchers at University of Hawaii; Iceland, where plume–ridge interaction is investigated by teams at University of Iceland and Brock University; Yellowstone National Park, examined by University of Utah and Idaho National Laboratory for mantle source and uplift; the Deccan Traps, analyzed by groups at Indian Institute of Science and University of Cambridge for plume head flood basalts; and Afghanistan-adjacent provinces and Siberian Traps explored for links between large igneous provinces and mass extinctions by scientists at Smithsonian Institution and Yale University.

Category:Geology