We use two-plane-wave tomography with a dense network of seismic stations across Sabah, northern Borneo, to image the shear wave velocity structure of the crust and upper mantle. Our model is used to estimate crustal thickness and the depth of the lithosphere-asthenosphere boundary (LAB) beneath the region. Calculated crustal thickness ranges between 25 and 55 km and suggests extension in a NW-SE direction, presumably due to back-arc processes associated with subduction of the Celebes Sea. We estimate the β-factor to be 1.3–2, well below the initiation of seafloor spreading. The LAB is, on average, at a depth of 100 km, which is inconsistent with models that ascribe Neogene uplift to wholescale removal of the mantle lithosphere. Instead, beneath a region of Plio-Pleistocene volcanism in the southeast, we image a region 50–100 km across where the lithosphere has thinned to <50 km, supporting recent suggestions of lower lithospheric removal through a Rayleigh-Taylor instability.

Greenfield, T., Gilligan, A., Pilia, S., Cornwell, D., Tongkul, F., Widiyantoro, S., et al. (2022). Post‐Subduction Tectonics of Sabah, Northern Borneo, Inferred From Surface Wave Tomography. GEOPHYSICAL RESEARCH LETTERS, 49(3) [10.1029/2021GL096117].

Post‐Subduction Tectonics of Sabah, Northern Borneo, Inferred From Surface Wave Tomography

Pilia, Simone
Membro del Collaboration Group
;
2022

Abstract

We use two-plane-wave tomography with a dense network of seismic stations across Sabah, northern Borneo, to image the shear wave velocity structure of the crust and upper mantle. Our model is used to estimate crustal thickness and the depth of the lithosphere-asthenosphere boundary (LAB) beneath the region. Calculated crustal thickness ranges between 25 and 55 km and suggests extension in a NW-SE direction, presumably due to back-arc processes associated with subduction of the Celebes Sea. We estimate the β-factor to be 1.3–2, well below the initiation of seafloor spreading. The LAB is, on average, at a depth of 100 km, which is inconsistent with models that ascribe Neogene uplift to wholescale removal of the mantle lithosphere. Instead, beneath a region of Plio-Pleistocene volcanism in the southeast, we image a region 50–100 km across where the lithosphere has thinned to <50 km, supporting recent suggestions of lower lithospheric removal through a Rayleigh-Taylor instability.
Articolo in rivista - Articolo scientifico
Borneo; LAB; lithospheric structure; post-subduction; Sabah; surface wave tomography;
English
28-gen-2022
2022
49
3
e2021GL096117
open
Greenfield, T., Gilligan, A., Pilia, S., Cornwell, D., Tongkul, F., Widiyantoro, S., et al. (2022). Post‐Subduction Tectonics of Sabah, Northern Borneo, Inferred From Surface Wave Tomography. GEOPHYSICAL RESEARCH LETTERS, 49(3) [10.1029/2021GL096117].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/350736
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