Journal cover Journal topic
Solid Earth An interactive open-access journal of the European Geosciences Union

Journal metrics

  • IF value: 3.495 IF 3.495
  • IF 5-year<br/> value: 3.386 IF 5-year
    3.386
  • CiteScore<br/> value: 3.70 CiteScore
    3.70
  • SNIP value: 0.783 SNIP 0.783
  • SJR value: 1.039 SJR 1.039
  • IPP value: 1.987 IPP 1.987
  • h5-index value: 20 h5-index 20
https://doi.org/10.5194/se-2017-142
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
30 Jan 2018
Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Solid Earth (SE).
3D numerical modelling of the re-distribution of partially molten lower crust rocks in relay zones between faults during transtension: Implications for the Sefwi terrane, SW Ghana
Xiaojun Feng1,2,3, Enyuan Wang1,2, Jérôme Ganne3, Roland Martin3, and Mark W. Jessell3,4 1Key Laboratory of Gas and Fire Control for Coal Mines, China University of mining and Technology, Ministry of Education, Xuzhou, 221116, China
2School of Safety Engineering, China University of Mining and Technology, Xuzhou, 221116, China
3Geosciences Environnement Toulouse, Observatoire Midi Pyrénées, Toulouse, 31400, France
4Centre for Exploration Targeting, The University of Western Australia, Perth, WA 6009, Australia
Abstract. High-grade tectono-metamorphic domains in the Sefwi terrane of Ghana are separated from adjacent low-grade greenstone belts by two main shear zones. The high-grade rocks are thought to have been exhumed along sinistral shear zones during the D2 ENE-WSW transtension. To better understand the role boundary conditions and the spatial relationship of faults play in the re-distribution of partially molten lower crust, ten 3D thermo-mechanical models have been constructed. The results show that the normal component of velocity boundary conditions mainly controls the exhumation of the lower crust which occurred along pre-existing faults, while the exhumation in the relay zones between faults is controlled by the ratio of extension rate to shear rate applied at the boundaries. The strike of the exhumation belt made of partially molten lower crust rocks in the relay zone is sub-orthogonal to the transtension direction. The isostatic compensation from low-density upper mantle to overlying crust (thinning) is higher under transtension than under extension.

The lower crust exhumation influenced by inherited shear zones can be used to better understand the loci of the high-grade rocks in the Sefwi terrane. We suggest that the Kukuom-Juaboso domain composed of up to amphibolite-migmatite facies probably resulted from the concentration of partially molten rocks in the relay zone between the Ketesso and Kenyase shear zones during the D2 ENE-WSW transtension. The two shear zones probably underwent two main stages for growth and maturation from the D1 to D2 deformation phases. The regional exhumation of the high-grade rocks in the Sefwi terrane probably occurred within a duration of less than 5Ma.

Citation: Feng, X., Wang, E., Ganne, J., Martin, R., and Jessell, M. W.: 3D numerical modelling of the re-distribution of partially molten lower crust rocks in relay zones between faults during transtension: Implications for the Sefwi terrane, SW Ghana, Solid Earth Discuss., https://doi.org/10.5194/se-2017-142, in review, 2018.
Xiaojun Feng et al.
Xiaojun Feng et al.
Xiaojun Feng et al.

Viewed

Total article views: 286 (including HTML, PDF, and XML)

HTML PDF XML Total BibTeX EndNote
230 46 10 286 1 9

Views and downloads (calculated since 30 Jan 2018)

Cumulative views and downloads (calculated since 30 Jan 2018)

Viewed (geographical distribution)

Total article views: 280 (including HTML, PDF, and XML)

Thereof 278 with geography defined and 2 with unknown origin.

Country # Views %
  • 1

Saved

Discussed

Latest update: 26 Apr 2018
Publications Copernicus
Download
Share