10.6084/m9.figshare.3453416.v1
S. E. Bryan
S. E.
Bryan
T. Orozco-Esquivel
T.
Orozco-Esquivel
L. Ferrari
L.
Ferrari
M. López-Martínez
M.
López-Martínez
Pulling apart the Mid to Late Cenozoic magmatic record of the Gulf of California: is there a Comondú Arc?
Geological Society of London
2016
rhyolitic
oceanic plate subduction
future site
Incorrect petrotectonic interpretations result
Western Mexico
Past tectonic interpretations
volcanism
Cenozoic magmatic record
source contributions
Gulf
mantle wedge
lithosphere
extension
Cenozoic magmatism
Comond
18 Ma
California
subducting Guadalupe Plate
rift environment
subduction processes
fluid flux
silicic compositions
km
Geology
2016-06-21 11:23:29
Dataset
https://geolsoc.figshare.com/articles/dataset/Pulling_apart_the_Mid_to_Late_Cenozoic_magmatic_record_of_the_Gulf_of_California_is_there_a_Comond_Arc_/3453416
<p>The composition of the lithosphere can be fundamentally altered by long-lived subduction processes such that subduction-modified
lithosphere can survive for hundreds of millions of years. Incorrect petrotectonic interpretations result when spatial–temporal–compositional
trends of, and source contributions to, magmatism are not properly considered. Western Mexico has had protracted Cenozoic
magmatism developed mostly in-board of active oceanic plate subduction beneath western North America. A broad range of igneous
compositions from basalt to high-silica rhyolite were erupted with intermediate to silicic compositions in particular, showing
calc-alkaline and other typical subduction-related geochemical signatures. A major Oligocene rhyolitic ignimbrite ‘flare-up’
(>300 000 km<sup>3</sup>) switched to a bimodal volcanic phase in the Early Miocene (<em>c.</em> 100 000 km<sup>3</sup>), associated with distributed extension and opening of numerous graben. Extension became more focused <em>c.</em> 18 Ma resulting in localized volcanic activity along the future site of the Gulf of California. This localized volcanism
(known as the Comondú ‘arc’) was dominantly effusive and andesite–dacite in composition. Past tectonic interpretations of
Comondú-age volcanism may have been incorrect as these regional temporal–compositional changes are alternatively interpreted
as a result of increased mixing of mantle-derived basaltic and crust-derived rhyolitic magmas in an active rift environment
rather than fluid flux melting of the mantle wedge above the subducting Guadalupe Plate.
</p>