Hunting for the Tristan Mantle Plume - An upper mantle tomography around the volcanic island of Tristan da Cunha.

Schlömer, Antje, Geissler, Wolfram H., Jokat, Wilfried and Jegen, Marion (2017) Hunting for the Tristan Mantle Plume - An upper mantle tomography around the volcanic island of Tristan da Cunha. Earth and Planetary Science Letters, 462 . pp. 122-131. DOI 10.1016/j.epsl.2016.12.028.

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Abstract

The active volcanic island Tristan da Cunha, located at the southwestern and youngest end of the Walvis Ridge - Tristan/Gough hotspot track, is believed to be the surface expression of a huge thermal mantle anomaly. While several criteria for the diagnosis of a classical hotspot track are met, the Tristan region also shows some peculiarities. Consequently it is vigorously debated if the active volcanism in this region is the expression of a deep mantle plume, or if it is caused by shallow plate tectonics and the interaction with the nearby Mid-Atlantic Ridge. Because of a lack of geophysical data in the study area, no model or assumption has been completely confirmed.
We present the first amphibian P-wave finite-frequency travel time tomography of the Tristan da Cunha region, based on cross-correlated travel time residuals of teleseismic earthquakes recorded by 24 ocean-bottom seismometers. The data can be used to image a low velocity structure southwest of the island. The feature is cylindrical with a radius of ~ 100 km down to a depth of 250 km. We relate this structure to the origin of Tristan da Cunha and name it the Tristan conduit. Below 250 km the low velocity structure ramifies into narrow veins, each with a radius of ~ 50 km. Furthermore, we imaged a linkage between young seamounts southeast of Tristan da Cunha and the Tristan conduit.

Document Type: Article
Keywords: Finite-frequency tomography, Ocean-bottom seismometers, Upper 10 mantle, Hotspot, Tristan da Cunha
Research affiliation: AWI
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1016/j.epsl.2016.12.028
ISSN: 0012-821X
Projects: SAMPLE, SPP 1375
Expeditions/Models/Experiments:
Date Deposited: 23 Jan 2017 09:09
Last Modified: 01 Feb 2019 15:02
URI: http://oceanrep.geomar.de/id/eprint/35621

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