Climate-driven compositional modifications of arc volcanoes along the East Equatorial Pacific Margin-The magmatic response to a cooling planet
Por:
Errazuriz-Henao, Carlos, Gomez-Tuena, Arturo, Parolari, Mattia, Weber, Marion
Publicada:
1 nov 2022
Categoría:
Earth and planetary sciences (miscellaneous)
Resumen:
Magmatic arcs modulate global climate over geological timescales through
outgassing and rock weathering, but recognizing the fingerprints of
climate change in arc magmas remains challenging. Here we combine
geologic, tectonic, and geochemical data of seafloor sediments and arc
volcanoes from the East Equatorial Pacific (EEP) to build a
biogeodynamic framework by which we can relate the compositions of arc
volcanoes to those of sub -ducted sediments, and by extension, to
regional and global environmental changes. Using this framework, we show
that the well-documented increases in biologically mediated authigenic
Ba and U contents of seafloor sediments at the onset of the so-called
``carbonate crash'' (12-9 Ma) were triggered by an escalation in
biological productivity and an augmented efficiency of respiratory
carbon storage. We suggest that the temporal modifi-cation of the
oceanic carbon cycle was not solely enabled by the uplift of the Panama
Isthmus, but also regulated by the synchronous formation of three
wind-powered seasonal upwellings systems -Tehuantepec, Papagayo, and
Panama- that developed in the context of steepening meridional
temperature gradients, intensified at-mospheric circulation and global
climate cooling since the Middle Miocene. Sediments deposited in the
context of these newly established upwelling systems became anomalously
enriched in authigenic U and Ba not only in comparison to older
sediments, but also with respect to geographically adjacent areas of the
EEP where vigorous upwellings are absent. These peculiar environmental
conditions thus produce a heterogeneous ocean floor that upon subduction
and eventual interaction with the mantle wedge creates arc volcanoes
with compositional fluctuations that mimic those of the ocean sediments.
These findings indicate that the oceanographic and biogeochemical
effects of climate change can be engraved on the silicate Earth.
Filiaciones:
Errazuriz-Henao, Carlos:
Univ Nacl Autonoma Mexico, Ctr Geociencias, Queretaro 76230, Mexico
Gomez-Tuena, Arturo:
Univ Nacl Autonoma Mexico, Ctr Geociencias, Queretaro 76230, Mexico
Parolari, Mattia:
Univ Nacl Autonoma Mexico, Inst Geol, Ciudad Univ, Cd Mx 04510, Mexico
Weber, Marion:
Univ Nacl Colombia, Fac Minas, Dept Geociencias & Medio Ambiente, Carrera 80 65-223, Medellin, Colombia
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