Origin Of Intraplate Volcanism Research Articles

The role of edge-driven convection in the generation of volcanism – Part 1: A 2D systematic study

Abstract. The origin of intraplate volcanism is not explained by plate tectonic theory, and several models have been put forward for explanation. One of these models involves edge-driven convection (EDC), in which cold and thick continental lithosphere is juxtaposed with warm and thin oceanic lithosphere to trigger convective instability. To test whether EDC can produce long-lived high-volume magmatism, we run numerical models of EDC for a wide range of mantle properties and edge (i.e., the oceanic–continental transition) geometries. We find that the most important parameters that govern EDC are the rheological parameters mantle viscosity η0 and activation energy Ea. However, even the maximum melting volumes predicted by our most extreme cases are insufficient to account for island-building volcanism on old seafloor, such as at the Canary Islands and Cabo Verde. Also, beneath old seafloor, localized EDC-related melting commonly transitions into widespread melting due to small-scale sublithospheric convection, inconsistent with the distribution of volcanism at these volcano chains. In turn, EDC is a good candidate to sustain the formation of small seamounts on young seafloor, as it is a highly transient phenomenon that occurs in all our models soon after initiation. In a companion paper, we investigate the implications of interaction of EDC with mantle plume activity (Manjón-Cabeza Córdoba and Ballmer, 2021).

Publisher Correction: Western US volcanism due to intruding oceanic mantle driven by ancient Farallon slabs

In the version of this Article originally published, data points representing mafic eruptions were missing from Fig. 4b, the corrected version is shown below. Furthermore, the authors omitted to include the following acknowledgements to the provider of the computational resources: “This research is part of the Blue Waters sustained-petascale computing project, which is supported by the National Science Foundation (awards OCI-0725070 and ACI-1238993) and the state of Illinois. Blue Waters is a joint effort of the University of Illinois at Urbana-Champaign and its National Center for Supercomputing Applications. This work is also part of the ‘PRAC Title 4-D Geodynamic Modeling With Data Assimilation: Origin Of Intra-Plate Volcanism In The Pacific Northwest’ PRAC allocation support by the National Science Foundation (award number ACI 1516586). This work also used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation grant number ACI-1548562.” Figure 4 and the Acknowledgements section have been updated in the online version of the Article.

Origin of intraplate volcanism in northeast China from Love wave constraints

AbstractThe tectonic source for widespread volcanism in northeast China has not been completely understood. We develop a 3‐D SH velocity model in NE China that provides new constraints to the origin of the volcanism. The 3‐D model is constructed from fundamental mode Love waves at the periods of 20–125 s recorded at 269 broadband seismic stations. The Changbai Mountain is characterized by a significant low velocity in the lower crust and uppermost mantle, which probably results from mantle upwelling due to the subduction of the Pacific plate. A fast and thin mantle lid of ~75 km is present beneath the Songliao Basin, indicating lithosphere extension from back‐arc rifting. The slow velocity in the middle and fast velocities in the south and north at 75–115 km depths in the Songliao Basin suggest complex mantle flow with upwelling and downwelling. Unlike the other volcanic fields (Changbaishan volcano, Jingpohu volcano, and Abaga volcano), the Halaha volcano has high velocity in the lower crust and upper mantle, implying a limited melt supply from mantle source recently. The subduction‐induced upwelling leads to complicated small‐scale mantle convection, which is responsible for the intraplate magmatism in northeast China.

Cocos Plate Seamounts offshore NW Costa Rica and SW Nicaragua: Implications for large-scale distribution of Galápagos plume material in the upper mantle

The origin of intraplate volcanism not directly part of a hotspot track, such as diffuse seamount provinces, and the extent of mantle plume influence on the upper mantle remain enigmatic. Here we present new 40Ar/39Ar age data and geochemical (major and trace-element and Sr-Nd-Pb isotopic) data from seamounts on the Cocos Plate presently located offshore of NW Costa Rica and SW Nicaragua. The seamounts (~ 7-24 Ma) require mixing of an enriched ocean island basalt composition, similar to that of the Northern Galapagos Domain, with two depleted components. One of the depleted components is similar to East Pacific Rise normal mid-ocean ridge basalt and the other has more depleted incompatible elements, either reflecting secondary melting of MORB or a depleted Galapagos plume component. Seamounts with ages significantly younger than the ocean crust formed in an intraplate setting and can be explained by northward transport of Galapagos plume material along the base of the Cocos Plate up to 900 km away from the hotspot and 250-500 km north of the Galapagos hotspot track. We propose that melting occurs due to decompression as the mantle upwells to shallower depth as it flows northwards, either due to changes in lithospheric thickness or as a result of upwelling at the edge of a viscous plug of accumulated plume material at the base of the lithosphere. The tholeiitic to alkaline basalt compositions of the Cocos Plate Seamounts compared to the more silica under-saturated compositions of Hawaiian rejuvenated and arch (alkali basalts to nephelinites) lavas is likely to reflect the significant difference in age (< 25 vs ~ 90 Ma) and thus thickness of the lithosphere on which the lavas were erupted.

Recycling of oceanic crust and the origin of intraplate volcanism

Source models for intraplate volcanism (IPV) include vertical introduction of material from deep in the mantle (plume model), contamination of the shallow mantle (perisphere and continental mantle delamination models) and derivation by selective partial melting of oceanic crust recycled into the depleted mantle (SUMA/streaky mantle models). The plume hypothesis became the ruling model after a flawed interpretation of helium isotope data in the mid 1980s that led to plumes being imposed on models for crustal recycling into the depleted mantle. This incorporation of otherwise competing concepts, is the cause of unnecessary complexity in modern geodynamic models. The plume model cannot explain all manifestations of IPV and a comprehensive explanation can only be found by invoking the alternative options, combined with their tapping by plate tectonic processes.

Implications for the origin of Hawaiian volcanism from a converted wave analysis of the mantle transition zone

The debate over the origin of intraplate volcanism has been ongoing since the discovery of age-progression at oceanic “hotspots.” The causes of such anomalous volcanic activity have been attributed to either deep-seated thermal plumes in the convecting mantle or shallower causes such as lithospheric structure and deformation or localized mantle flow. Data from the Hawaiian Plume–Lithosphere Undersea Melt Experiment (PLUME) have made it possible to provide detailed images of upper mantle heterogeneity beneath the Hawaiian Islands with much greater resolution than previous experiments. Using receiver function analysis, we determine the depth to and topography along the mantle transition zone discontinuities. Our results indicate that the 410-km discontinuity deepens from northwest to southeast beneath the Hawaiian Islands, corresponding to an average thermal anomaly of ∼325K located beneath and southeast of the Big Island of Hawaii. In general, temperatures remain elevated by at least ∼150K directly beneath the Big Island, as far as 200km away from the hottest measurement inferred from the discontinuity structure. Heterogeneity at these length scales raises questions about rheology, convective circulation, and melt transport in the mantle. Our results also robustly indicate the presence of a low-velocity converter in the deep upper mantle, which carries additional implications for melt transport, volatile budget, and chemical composition of the hotspot source.

One hundred million years of mantle geochemical history suggest the retiring of mantle plumes is premature

Linear chains of intraplate volcanoes and their geochemistry provide a record of mantle melting through geological time. The isotopic compositions of their lavas characterize their mantle sources, and their ages help backtrack these volcanoes to their original, eruptive source regions. Such data may shed light on a much-debated issue in Earth Sciences: the origin of intraplate volcanism and its underlying mantle and lithosphere dynamics. We show here that three major Western Pacific Seamount groups, ∼ 50–100 million years in age, display distinct Sr, Nd, Hf, and Pb isotopic signatures that can be traced back in time, both geographically and geochemically, to three separate, recently-active intraplate volcanoes in the South Pacific Cook–Austral Islands. Their unique 100 million year history, which shows a persistent geochemical fingerprint, suggests formation from large volumes of laterally fixed, long-lived source regions. Such longevity is unlikely to be attained in the relatively dynamic upper mantle. Therefore, these sources are likely anchored deep in the mantle, isolated from homogenization by mantle convection, and imply a primary origin from deep mantle plumes rather than resulting from lithosphere extension.

Critical evaluation of Re–Os and Pt–Os isotopic evidence on the origin of intraplate volcanism

Evaluation of Re–Os and Pt–Os isotope systematics indicates that the mantle plume model does not provide a unique explanation of the 187Os/ 188Os– 186Os/ 188Os isotopic variation in intraplate volcanic rocks. The low Os contents of ocean floor basalt and sediment compositions results in the amount of recycled crust (up to 55%) required in a plume to explain the range in 187Os/ 188Os, being unrealistically high unless non-equilibrium melting conditions are invoked. The low Pt content of MORB also limits the Pt/Os ratio of recycled crust, requiring plume models to resort to interaction with the outer core to explain suprachondritic 186Os/ 188Os ratios. Generation of the sources of intraplate volcanism by mixing of sediment into the mantle similarly requires high amounts (30–50%) of crustal materials. Non-equilibrium melting regimes can be avoided when the sources for intraplate volcanism are formed by metasomatic processes at shallow level in the mantle. Wetspot compositions formed by fluid metasomatism at convergent margins could produce the range of 186Os/ 188Os– 187Os/ 188Os signatures in intraplate volcanism over 2 Gyrs if the fluid was derived principally from the slab sediment component and the Pt/Os and Re/Os ratios of the hydrous peridotite remained unmodified. However, the most feasible method of generating suprachondritic 186Os/ 188Os– 187Os/ 188Os is from partitioning of platinum group elements into pyroxenites precipitated from Mg-rich melts. Isotopic compositions of 186Os/ 188Os=0.119850, γOs=+10 could be generated from depleted mantle compositions in 150 Myrs in an oceanic perisphere domain containing 60–70% pyroxenite veins, or in a continental mantle section containing as little as 15% pyroxenite over 2 Gyrs. Osmium isotope systematics therefore do not prove the mantle plume over alternative models, as illustrated for the Columbia River Basalt Group, where 187Os/ 188Os ratios of up to 0.144 in the least crustally contaminated basalts can be explained with a source containing 15–35% Mesozoic pyroxenite.