Pervasive Hydrothermal Events Associated with Large Igneous Provinces Documented by the Columbia River Basaltic Province.

ABSTRACT: The degree and extent of crustal hydrothermal alteration related to the eruption of large igneous provinces is poorly known and not easily recognizable in the field. We here report a new δ¹⁸O dataset for dikes and lavas from the Columbia River Basalt Group (16-15 Ma) in the western USA, and document that dikes on average are 1-2‰ more depleted in δ¹⁸O than basalt flows. We show that this observation is best explained with the involvement of heated meteoric  waters during their cooling in the crust. The largest 6-8‰ depletion is found around and inside a 10 m-thick feeder dike that intruded the 125 Ma Wallowa tonalitic batholith. This dike likely operated as a magma conduit for 4-7 years, based on the extent of heating and melting its host rocks. We show that this dike

SUBMITTER: Bindeman IN 

PROVIDER: S-EPMC7311473 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature