Preprints
https://doi.org/10.5194/se-2020-153
https://doi.org/10.5194/se-2020-153

  28 Sep 2020

28 Sep 2020

Review status: a revised version of this preprint was accepted for the journal SE and is expected to appear here in due course.

The preserved plume of the Caribbean Large Igneous Plateau revealed by 3D data-integrative models

Ángela María Gómez-García1,2,3, Eline Le Breton4, Magdalena Scheck-Wenderoth1, Gaspar Monsalve2, and Denis Anikiev1 Ángela María Gómez-García et al.
  • 1GFZ German Research Centre for Geosciences, Potsdam, 14473, Germany
  • 2Universidad Nacional de Colombia – Medellín, Facultad de Minas
  • 3CEMarin – Corporation Center of Excellence in Marine Sciences
  • 4Institute of Geological Sciences, Freie Universität Berlin, Berlin, 12249, Germany

Abstract. Remnants of the Caribbean Large Igneous Plateau (CLIP) are found as thicker than normal oceanic crust in the Caribbean Sea, that formed during rapid pulses of magmatic activity at ~ 91–88 Ma and ~ 76 Ma. Strong geochemical evidence supports the hypothesis that the CLIP formed due to melting of the plume head of the Galápagos hotspot, which interacted with the Farallon (Proto-Caribbean) plate in the east Pacific. Considering the plate tectonics theory, it is expected that the lithospheric portion of the plume-related material migrated within the Proto-Caribbean plate, in a north–north-eastward direction, developing the present-day Caribbean plate. In this research, we used 3D lithospheric-scale, data-integrative models of the current Caribbean plate setting to reveal, for the first time, the presence of positive density anomalies in the uppermost lithospheric mantle. These models are based on the integration of up-to-date geophysical datasets, from the Earth’s surface down to 200 km depth, which are validated using high-resolution free-air gravity measurements. Based on the gravity residuals (modelled minus observed gravity), we derive density heterogeneities both in the crystalline crust and the uppermost oceanic mantle (< 50 km). Our results reveal the presence of two positive mantle density anomalies beneath the Colombian and the Venezuelan basins, interpreted as the preserved fossil plume conduits associated with the CLIP formation. Such mantle bodies have never been identified before, but a positive density trend is also indicated by S-wave tomography, at least down to 75 km depth. The interpreted plume conduits spatially correlate with the thinner crustal regions present in both basins; therefore, we to propose a modification to the commonly accepted tectonic model of the Caribbean, suggesting that the thinner domains correspond to the centres of uplift due to the income of the hot, buoyant plume head. Finally, using six different kinematic models, we test the hypothesis that the CLIP originated above the Galápagos hotspot; however, misfits of up to ~ 3000 km are found between the present-day hotspot location and the mantle anomalies, reconstructed back to 90 Ma. Therefore, we shed light on possible sources of error responsible for this offset and discuss two possible interpretations: (1) The Galápagos hotspot migrated (~ 1200–3000 km) westward while the Caribbean plate moved to the north, or (2) The CLIP was formed by a different plume, which – if considered fixed – would be nowadays located below the South American continent.

Ángela María Gómez-García et al.

 
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
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Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement

Ángela María Gómez-García et al.

Ángela María Gómez-García et al.

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