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

<p<Remnants of the Caribbean Large Igneous Plateau (C-LIP) are found as thicker than normal oceanic crust in the Caribbean Sea that formed during rapid pulses of magmatic activity at <span class="inline-formula"<∼91</span<–88 and <span class="inline-formula"<∼76</span< Ma. Strong geochemical evidence supports the hypothesis that the C-LIP formed due to melting of the plume head of the Galápagos hotspot, which interacted with the Farallon (Proto-Caribbean) plate in the eastern Pacific. Considering 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 <span class="inline-formula"<km</span< 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 (<span class="inline-formula"<&lt;50</span< <span class="inline-formula"<km</span<). 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 C-LIP 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 <span class="inline-formula"<km</span< depth. The interpreted plume conduits spatially correlate with the thinner crustal regions present in both basins; therefore, we 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 inflow of the hot, buoyant plume head. Finally, using six different kinematic models, we test the hypothesis that the C-LIP originated above the Galápagos hotspot; however, misfits of up to <span class="inline-formula"<∼3000</span< <span class="inline-formula"<km</span< are found between the present-day hotspot location and the mantle anomalies, reconstructed back to 90 <span class="inline-formula"<Ma</span<. Therefore, we shed light on possible sources of error responsible for this offset and discuss two possible interpretations: (1) the Galápagos hotspot migrated (<span class="inline-formula"<∼1200</span<–3000 <span class="inline-formula"<km</span<) westward while the Caribbean plate moved to the north, or (2) the C-LIP was formed by a different plume, which – if considered fixed – would be nowadays located below the South American continent.</p<.

Medienart:	E-Artikel

Erscheinungsjahr:	2021
Erschienen:	2021

Enthalten in:	Zur Gesamtaufnahme - volume:12
Enthalten in:	Solid Earth - 12(2021), Seite 275-298

Sprache:	Englisch

Beteiligte Personen:	Á. M. Gómez-García [VerfasserIn] Á. M. Gómez-García [VerfasserIn] Á. M. Gómez-García [VerfasserIn] Á. M. Gómez-García [VerfasserIn] E. Le Breton [VerfasserIn] M. Scheck-Wenderoth [VerfasserIn] G. Monsalve [VerfasserIn] D. Anikiev [VerfasserIn]

Links:	doi.org [kostenfrei] doaj.org [kostenfrei] se.copernicus.org [kostenfrei] Journal toc [kostenfrei] Journal toc [kostenfrei]

Themen:	Geology Stratigraphy

doi:	10.5194/se-12-275-2021

funding:
Förderinstitution / Projekttitel:

PPN (Katalog-ID):	DOAJ056162901