Hunting for the Tristan mantle plume – An upper mantle tomography around the volcanic island of Tristan da Cunha

Schlömer, Antje; Geissler, Wolfram; Jokat, Wilfried; Jegen, Marion

doi:10.1016/j.epsl.2016.12.028

Cited by 36 publications

(49 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The correlation suggests farther area of recent volcanic or intrusive activity. The occurrence of earthquakes in different clusters (c1–c3) in addition with the recent discovery of the Isolde seamount and new volcanic fields supports the theory of Schlömer et al () that material is channeled from the Tristan plume to specific locations at the seafloor. Ryberg et al () recently analyzed ambient seismic noise around TdC and derived a 3‐D S wave velocity model.…”

Section: Interpretation and Discussionsupporting

confidence: 78%

“…This schematic display is derived from a picture published by Van Wijk and Blackman (), showing the extensional forces σ xx , calculated for a 100 km transform fault. The red dashed ellipse marks the Tristan plume location published by Schlömer et al (), and the gray ellipse marks the area, where the plume influences the plate rheology.…”

Section: Interpretation and Discussionmentioning

confidence: 99%

“…Overview map with main interpretations: Border of the Tristan da Cunha conduit (Schlömer et al, ) coincides with an aseismic area. Sinistral fault mechanism at the plate segment north of TdC.…”

Section: Interpretation and Discussionmentioning

confidence: 99%

“…The discussed fracture zones are the Northern Fracture Zone (NFZ), a small Fracture Zone (small FZ), the Tristan da Cunha Fracture Zone (TdCFZ), and the Southern Fracture Zone (SFZ). The Northern Transform Fault (NTF), the Mid‐Atlantic Ridge (MAR), and the location of the Tristan conduit found by P wave tomography (after Schlömer et al, ) (red dashed ellipsoid) are also marked. The inset map shows the study area (black framed) and the main plate boundaries (red).…”

Section: Introductionmentioning

confidence: 99%

“…It has long been accepted that melts derived from a mantle plume directly beneath the island formed the archipelago (O'Connor & Duncan, ; Rohde et al, ). Schlömer et al () recently imaged a plume conduit southwest of TdC by calculating a P wave tomography with data registered by the seismological network also used for this study. Their study also proposed that hot plume material is currently being channeled along the base of the lithosphere toward the islands and nearby seamounts.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Seismicity in the Vicinity of the Tristan Da Cunha Hot Spot: Particular Plate Tectonics and Mantle Plume Presence

et al. 2017

Self Cite

View full text Add to dashboard Cite

Earthquake locations along the southern Mid‐Atlantic Ridge have large uncertainties due to the sparse distribution of permanent seismological stations in and around the South Atlantic Ocean. Most of the earthquakes are associated with plate tectonic processes related to the formation of new oceanic lithosphere, as they are located close to the ridge axis or in the immediate vicinity of transform faults. A local seismological network of ocean‐bottom seismometers and land stations on and around the archipelago of Tristan da Cunha allowed for the first time a local earthquake survey for 1 year. We relate intraplate seismicity within the African oceanic plate segment north of the island partly to extensional stresses induced by a bordering large transform fault and to the existence of the Tristan mantle plume. The temporal propagation of earthquakes within the segment reflects the prevailing stress field. The strong extensional stresses in addition with the plume weaken the lithosphere and might hint at an incipient ridge jump. An apparently aseismic zone coincides with the proposed location of the Tristan conduit in the upper mantle southwest of the islands. The margins of this zone describe the transition between the ductile and the surrounding brittle regime. Moreover, we observe seismicity close to the islands of Tristan da Cunha and nearby seamounts, which we relate to ongoing tectono‐magmatic activity.

show abstract

Section: Interpretation and Discussionsupporting

confidence: 78%

Section: Interpretation and Discussionmentioning

confidence: 99%

Section: Interpretation and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Seismicity in the Vicinity of the Tristan Da Cunha Hot Spot: Particular Plate Tectonics and Mantle Plume Presence

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

Hot Upper Mantle Beneath the Tristan da Cunha Hotspot From Probabilistic Rayleigh‐Wave Inversion and Petrological Modeling

Bonadio

Geissler

Lebedev

et al. 2018

Geochem Geophys Geosyst

Self Cite

View full text Add to dashboard Cite

Understanding the enigmatic intraplate volcanism in the Tristan da Cunha region requires knowledge of the temperature of the lithosphere and asthenosphere beneath it. We measured phase‐velocity curves of Rayleigh waves using cross‐correlation of teleseismic seismograms from an array of ocean‐bottom seismometers around Tristan, constrained a region‐average, shear‐velocity structure, and inferred the temperature of the lithosphere and asthenosphere beneath the hotspot. The ocean‐bottom data set presented some challenges, which required data‐processing and measurement approaches different from those tuned for land‐based arrays of stations. Having derived a robust, phase‐velocity curve for the Tristan area, we inverted it for a shear wave velocity profile using a probabilistic (Markov chain Monte Carlo) approach. The model shows a pronounced low‐velocity anomaly from 70 to at least 120 km depth. VnormalS in the low velocity zone is 4.1–4.2 km/s, not as low as reported for Hawaii (∼4.0 km/s), which probably indicates a less pronounced thermal anomaly and, possibly, less partial melting. Petrological modeling shows that the seismic and bathymetry data are consistent with a moderately hot mantle (mantle potential temperature of 1,410–1,430°C, an excess of about 50–120°C compared to the global average) and a melt fraction smaller than 1%. Both purely seismic inversions and petrological modeling indicate a lithospheric thickness of 65–70 km, consistent with recent estimates from receiver functions. The presence of warmer‐than‐average asthenosphere beneath Tristan is consistent with a hot upwelling (plume) from the deep mantle. However, the excess temperature we determine is smaller than that reported for some other major hotspots, in particular Hawaii.

show abstract

Two‐Branch Break‐up Systems by a Single Mantle Plume: Insights from Numerical Modeling

Beniest

Koptev

Leroy

et al. 2017

Geophysical Research Letters

View full text Add to dashboard Cite

Thermomechanical modeling of plume‐induced continental break‐up reveals that the initial location of a mantle anomaly relative to a lithosphere inhomogeneity has a major impact on the geometry and timing of a rift‐to‐spreading system. Models with a warmer Moho temperature are more likely to result in “plume‐centered” mode, where the rift and subsequent spreading axis grow directly above the plume. Models with weak far‐field forcing are inclined to develop a “structural‐inherited” mode, with lithosphere deformation localized at the lateral lithospheric boundary. Models of a third group cultivate two break‐up branches (both “plume‐centered” and “structural inherited”) that form consecutively with a few million years delay. With our experimental setup, this break‐up mode is sensitive to relatively small lateral variations of the initial anomaly position. We argue that one single mantle anomaly can be responsible for nonsimultaneous initiation and development of two rift‐to‐spreading systems in a lithosphere with a lateral strength contrast.

show abstract

Hunting for the Tristan mantle plume – An upper mantle tomography around the volcanic island of Tristan da Cunha

Cited by 36 publications

References 49 publications

Seismicity in the Vicinity of the Tristan Da Cunha Hot Spot: Particular Plate Tectonics and Mantle Plume Presence

Seismicity in the Vicinity of the Tristan Da Cunha Hot Spot: Particular Plate Tectonics and Mantle Plume Presence

Hot Upper Mantle Beneath the Tristan da Cunha Hotspot From Probabilistic Rayleigh‐Wave Inversion and Petrological Modeling

Two‐Branch Break‐up Systems by a Single Mantle Plume: Insights from Numerical Modeling

Contact Info

Product

Resources

About