Source and mobility of Rare Earth Elements in a sedimentary aquifer system: Aquitaine basin Southern FranceReport as inadecuate




Source and mobility of Rare Earth Elements in a sedimentary aquifer system: Aquitaine basin Southern France - Download this document for free, or read online. Document in PDF available to download.

1 BRGM - Bureau de Recherches Géologiques et Minières

Abstract : The large Eocene Sand aquifer system of the Aquitaine sedimentary basin was studied through various hydrological, chemical and isotopic tools. This system extends over 116,000 km² in the South west part of the French territory. The aquifer being artesian in the west of the district and confined with piezometric levels around 250-m depth in the east. The -Eocene Sands-, composed of sandy Tertiary sediments alternating with carbonate deposits, is a multi-layer system with high permeability and a thickness of several tens of metres to a hundred metres. The Eocene Sand aquifer system comprises at least five aquifers: Paleocene, Eocene infra-molassic sands IMS, early Eocene, middle Eocene, and late Eocene. One important feature, in these confined systems isolated from anthropogenic influence, is the range in salinities by a factor of 10, from 250 mg-L up to 2.5 g-L. The ΣREE, in the range 2-54 ng-L, with a dependence on salinity when expressed in % HCO3 or SO4, reflect the carbonate or evaporite source of REEs. The UCC normalized-REE patterns show a large variability as exemplified by the REE flat patterns-low SREE associated with salinity controlled by HCO3.





Author: Philippe Négrel - Emmanuelle Petelet Giraud - Romain Millot - Eline Malcuit -

Source: https://hal.archives-ouvertes.fr/



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