On the cause of continental breakup: A simple analysis in terms of driving mechanisms of plate tectonics and mantle plumes

The existence, spatial distribution, and style of volcanism on terrestrial planets is an expression of their internal dynamics and evolution. On Earth a physical link has been proposed between hot spots, regions with particularly persistent, localized, and high rates of volcanism, and underlying deep mantle plumes. Such mantle plumes are thought to be constructed of large spherical heads and narrow trailing conduits. This plume model has provided a way to interpret observable phenomena including the volcanological, petrological, and geochemical evolution of ocean island volcanoes, the relative motion of plates, continental breakup, global heat flow, and the Earth's magnetic field within the broader framework of the thermal history of our planet. Despite the plume model's utility the underlying dynamics giving rise to hot spots as long‐lived stable features have remained elusive. Accordingly, in this review we combine results from new and published observational, analog, theoretical, and numerical studies to address two key questions: (1) Why might mantle plumes in the Earth have a head‐tail structure? (2) How can mantle plumes and hot spots persist for large geological times? We show first that the characteristic head‐tail structure of mantle plumes, which is a consequence of hot upwellings having a low viscosity, is likely a result of strong cooling of the mantle by large‐scale stirring driven by plate tectonics. Second, we show that the head‐tail structure of such plumes is a necessary but insufficient condition for their longevity. Third, we synthesize seismological, geodynamic, geomagnetic, and geochemical constraints on the structure and composition of the lowermost mantle to argue that the source regions for most deep mantle plumes contain dense, low‐viscosity material within D″ composed of partial melt, outer core material, or a mixture of both (i.e., a “dense layer”). Fourth, using results from laboratory experiments on thermochemical convection and new theoretical scaling analyses, we argue that the longevity of mantle plumes in the Earth is a consequence of the interactions between plate tectonics, core cooling, and dense, low‐viscosity material within D″. Conditions leading to Earth‐like mantle plumes are highly specific and may thus be unique to our own planet. Furthermore, long‐lived hot spots should not a priori be anticipated on other terrestrial planets and moons. Our analysis leads to self‐consistent predictions for the longevity of mantle plumes, topography on the dense layer, and composition of ocean island basalts that are consistent with observations.

The longest voyage: Tectonic, magmatic, and paleoclimatic evolution of the Indian plate during its northward flight from Gondwana to Asia

Continental rifting parallel to ancient collisional belts: an effect of the mechanical anisotropy of the lithospheric mantle

On the great plume debate

Based on the former workers’ study results such as numerical simulation of fluid mechanics, seismic tomography of the whole earth and igneous rocks, the basic characteristics of mantle plumes are summarized in detail, namely the mantle plume, from the D″ layer near the core-mantle boundary (CMB) of 2900 km deep, is characterized by the shape of large head and thin narrow conduit, by the physical property of high temperature and low viscosity. The LIP (large igneous province) is the best exhibition when the mantle plume ascends to the surface. According to the basic characteristics of the mantle plumes and the LIP, as well as the temporal-spatial relationships between the mantle plume and continental breakup, the detailed research on petrology, geochemistry, temporal-spatial distribution, tectonic background of the Cenozoic-Mesozoic igneous rocks and gravity anomaly distribution in East China has been done. As a result, the Mesozoic igneous rocks in Southeast China should not be regarded as an example of typical LIP related to mantle plumes, for their related characteristics are not consistent with those of the typical LIPs related to mantle plumes. The Cenozoic igneous rocks in Northeast China have no the typical characteristics of mantle plumes and hotspots, so the Cenozoic volcanism in Northeast China might have no the direct relationships with the activity of mantle plumes.

A review of Wilson Cycle plate margins: A role for mantle plumes in continental break-up along sutures?

In early Permian, a mantle plume heated up the Tarim block and formed the Tarim large igneous province. It is an interesting phenomenon to explore the interaction between mantle plume and a thick continent lithosphere, because mantle plume has been proposed to be an important route of material and energy transportation in the earth. Currently, the Tarim block is surrounded by Tibetan plateau to its south edge and Tian Shan orogeny to its north edge. The combined effects of both mantle plume activity and plate tectonics should have significantly changed the structure and composition of the Tarim block because of its amalgamations in Neoproterozoic. Seismic imaging plays a key role on revealing the deep structure of the Earth, which could help unravel the questions mentioned before. However, the harsh natural environment in the central part of the Tarim basin, the Taklimakan desert—the largest desert in China—has seriously hampered the broadband seismological observation. From July 2017 to November 2019, the Institute of Geology and Geophysics, Chinese Academy of Sciences deployed a 2D broadband seismic array named the Tarim seismic Array for lithoSpheric signaTure of mantle plumE (TASTE) over the inner part of the Tarim basin with an averaged spacing of 60–70 km. The primary target of this project is to obtain a detailed lithospheric structure to resolve the possible lithospheric signatures of Permian mantle plume activity. Here we introduce the basic information of the TASTE network and the performance of these instruments by analyzing the background noise level. Preliminary results of receiver function and ambient noise analyses are also shown, which may suggest a thick sedimentary layer, as well as complicated crust and lithospheric feature.

Neon isotopes in mantle rocks from the Red Sea region reveal large-scale plume–lithosphere interaction

WITHDRAWN: On the cause of continental breakup: A simple analysis in terms of driving mechanisms of plate tectonics and mantle plumes

When a mantle plume with elevated temperature underlies an oceanic spreading centre it
\naffects the generation of oceanic crust by creating thicker crust. We map the variation in
\ncrustal thickness and seismic velocity along three long-offset seismic profiles acquired over
\noceanic crust generated shortly after continental breakup in the North Atlantic: a 212-kmlong
\nflowline from the Faroes rifted continental margin across crust of 51–42 Ma age, where
\noceanic spreading developed close to the inferred centre of the Iceland mantle plume; a 256 km
\nflowline extending from the Hatton rifted continental margin across crust of 52–40 Ma age,
\nabout 800 km south of the presumed centre of the mantle plume; and a 99 km strike line over
\noceanic crust formed at 43 Ma in the Iceland Basin off the Hatton continental margin. The
\ncrustal velocity structure along each profile is constrained by multichannel seismic reflection
\ndata, which is used primarily to map the sediments, and by densely spaced ocean-bottom
\nseismometers, which recorded wide-angle reflections and refractions to offsets of more than
\n100 km. Over 56 000 crustal diving wave and Moho wide-angle reflection arrivals were used in
\njoint crustal refraction and reflection tomographic inversions. Quantitative error analysis shows
\nthat the seismic velocity of the crust is mostly constrained to within 0.1 km s−1 and the depth
\nof the Moho to within ±250 m. We interpret the crustal thickness and velocity changes along
\nthe profiles as caused primarily by changes in the mantle temperature at the time of crustal
\nformation. If all the oceanic crustal thickness variations are ascribed to mantle temperature
\nchanges, we infer that as mature seafloor spreading developed following continental breakup,
\nthe mantle cooled by ca. 75 ◦C over a 10 Myr period, although it still remained hotter than
\nthe global average of normal oceanic crust. The crust formed close to Iceland is at all times
\nthicker than that formed further away, which we interpret as reflecting higher temperatures
\nclose to the centre of the thermal anomaly created by the mantle plume. Currently at the
\nReykjanes Ridge, south of Iceland, we interpret thicker than normal oceanic crust as being
\ncaused by the presence of hotter mantle, modulated by thickness variations of 1.5–2.0 km
\nwhich are attributed to temporal variations in the mantle plume temperature of about 25 ◦C
\non a 3–6 Myr timescale. A 1.5 km increase in thickness of oceanic crust generated between
\n48 and 45 Ma on the Faroes line is similar in magnitude and duration to those occurring on
\nthe present day Reykjanes Ridge, which we suggest is due to a temperature pulse of ∼25 ◦C.
\nGravity lineations in the northern North Atlantic suggest that the oceanic crust has exhibited
\nsmall thickness fluctuations of similar size throughout its history, interpreted as due to small
\nfluctuations in the temperature of the Iceland mantle plume.

Mantle plumes have played a key role in tectonic events such as continental break-up and large magmatic events since at least the formation of Gondwana. However, as their signatures on Earth’s surface, many of large igneous provinces have disappeared into the mantle during Earth’s long-term evolution, meaning that plume remnants in the mantle are crucial in advancing mantle plume theory and accurately reconstructing Earth history. Here we present an electrical conductivity model for North Asia constructed from geomagnetic data. The model shows a large high-electrical-conductivity anomaly in the mantle transition zone beneath the Siberian Traps at the time of their eruption that we interpret to be a thermal anomaly with trace amounts of melt. This anomaly lies almost directly over an isolated low-seismic-wave-velocity anomaly known as the Perm anomaly. The spatial correlation of our anomaly with the Siberian Traps suggests that it represents a remnant of a superplume that was generated from the Perm anomaly. This plume was responsible for the late Permian Siberian large igneous province. The model strengthens the validity of the mantle plume hypothesis.

John Tuzo Wilson (1908–1993) was one of the greatest Canadian scientists of the 20th century. His contributions to Earth Sciences, leading the formulation of the theory of plate tectonics, have revolutionized our understanding of how the planet Earth works and evolved over the past 4 billion years. This 50th anniversary special issue of the Canadian Journal of Earth Sciences is dedicated in honour of John Tuzo Wilson, who inspired tens of thousands of students all around the world to study the Earth. This special issue contains 12 papers dealing with various aspects of the “Wilson Cycle” in the geologic record, plate tectonics, mantle plumes, and how John Tuzo Wilson accepted “continental drift” and formulated the theory of plate tectonics. The contributions have mostly been made by geoscientists who directly or indirectly associated with John Tuzo Wilson and have contributed significantly to the plate tectonics paradigm.

Did the Neoproterozoic Revolution Extend to the Deep Mantle?

Volcanism in the earliest stage of back-arc rifting in the Izu-Bonin arc revealed by laser-heating 40Ar/ 39Ar dating

The true driving force behind drifts in plate tectonics is still a topic open for discussion. Currently, slab pull is taken as the dominant driving force. From the energy perspective, heat from the Earth’s interior is the main source of power maintaining plate tectonics. The organized release of heat is the key to transforming static energy into kinetic energy. Here we propose a Magma Engine model. According to this model, heat is changed to potential energy through magmatism, and this consequently drives movements in plate tectonics through gravity. New oceanic crust is formed continuously at the mid-Ocean ridges, and then cools down gradually. The newly formed oceanic crust is lighter and thinner than the older ones, resulting in tilted plates sitting on the asthenosphere mantle. Given that the mantle has a high viscosity of 1019−1021 in the asthenosphere, and even higher values further down, the oceanic plate would lie on a big slope, with a height difference of around 80 kilometers. The highest plate sliding forces reach 1.4 ´ 1014 N/m, which is an order of magnitude larger than the estimated value of slab pull. It is therefore the primary driving force of plate tectonics. Mantle plume is another type of Magma Engine. Large plume heads may elevate the overlying continental crust in kilometer scales, due to high temperatures and the bouncy of large amounts of plume magma. Such uplifting may lead to the overlying plate sliding away from the center of the plume. This may initiate plate subduction along weaker belts in case the plume is big enough and the overlying plate is strong enough. This is likely the main mechanism that initiated plate tectonics in the early history of the Earth. Under the plate tectonic system, the plume head plays a major role in the opening of new ocean basins, acting as an “igniter” of mid-ocean Magma Engines. There are two types of subduction initiations, spontaneous and induced (or forced). Spontaneous subduction initiation usually occurs in old ocean basins, forming double-track subductions on either side of the ocean basin. In contrast, induced subduction initiation usually occurs in young ocean basins, forming single-track subduction. The closures of Neo-Tethys Oceans were likely associated with induced subduction initiation, which always forms northward subductions. The Magma Engine works mainly on plates that are directly connected to spreading ridges and/or mantle plumes. For others, the energy for plate movement and deformation comes from plate interactions.