@misc{10481/57997,
year = {2019},
month = {9},
url = {http://hdl.handle.net/10481/57997},
abstract = {Three types of glaucony grains were identified in the late Eocene (~35.5–34.1 Ma) sediments from
Ocean Drilling Program (ODP) Hole 696B in the northwestern Weddell Sea (Antarctica). The grains are
K2O-rich (~7 wt%) and formed by smectite-poor interstratified ~10 Å glauconite-smectite with flaky/
rosette-shaped surface nanostructures. Two glaucony types reflect an evolved (types 1 and 2 glaucony;
less mature to mature) stage and long term glauconitization, attesting to the glaucony grains being
formed in situ, whereas the third type (type 3 glaucony) shows evidences of alteration and reworking
from nearby areas. Conditions for the glaucony authigenesis occurred in an open-shelf environment
deeper than 50 m, under sub-oxic conditions near the sediment-water interface. These environmental
conditions were triggered by low sedimentation rates and recurrent winnowing action by bottomcurrents,
leading to stratigraphic condensation. The condensed glaucony-bearing section provides an
overview of continuous sea-level rise conditions pre-dating the onset of Antarctic glaciation during the
Eocene-Oligocene transition. Sediment burial, drop of O2 levels, and ongoing reducing (postoxic to
sulphidic) conditions at Hole 696B, resulting in iron-sulphide precipitation, were a key limiting factor for
the glauconitization by sequestration of Fe2+.},
organization = {Funding for this research is provided by the Spanish Ministry of
Science and Innovation (grants CTM2014-60451-C2-1-P and CTM2017-89711-C2-1-P, CGL2016-75679P) cofunded
by the European Union through FEDER funds and RNM-208 group (Discontinuidades estratigráficas,
Junta de Andalucía, Spain).},
publisher = {Springer Nature},
title = {Glaucony authigenesis, maturity and alteration in the Weddell Sea: An indicator of paleoenvironmental conditions before the onset of Antarctic glaciation},
doi = {10.1038/s41598-019-50107-1},
author = {López Quirós, Adrián and Escutia Dotti, Carlota and Sánchez Navas, Antonio and Nieto García, Fernando and García Casco, Antonio and Martín Algarra, Agustín and Evangelinos, Dimitris and Salabarnada, Ariadna},
}