The problem of glaucony from the Shannon Sandstone (Campanian, Wyoming)

Abstract

Terra Nova, 23, 100–107, 2011 Abstract The Shannon Sandstone, one of the most controversial units in the field of stratigraphy, was first interpreted as a shelf sand‐ridge deposit, but subsequent studies have furnished different interpretations, from lowstand‐shoreface to incised‐valley models. Despite a general consensus among previous workers about the significance of glaucony for Shannon interpretation, mineralogical characterization of the green grains has never been undertaken: identification of glaucony has been restricted to visual inspection. Accurate characterization of ‘highly glauconitic’ deposits from the Shannon Sandstone (Powder River Basin of Wyoming, Section W3) reveals that sedimentological interpretation of the greensands relies mostly upon mistaken mineral identity. Glaucony appears as a minor component of the rock and proves to be poorly mature and significantly less abundant (0–6%) than previously inferred (up to 85%). Characterization of the glauconitic minerals, however, provides data that contribute to Shannon interpretation.

Unusual seawater composition of the Late Cretaceous Tethys imprinted in glauconite of Narmada basin, central India

“…Glauconite is an excellent marker of stratigraphic condensation associated with transgressive deposits (Amorosi, 1995(Amorosi, , 1997(Amorosi, , 2011Amorosi & Centineo, 1997;Banerjee et al 2012aBanerjee et al , b, 2015Banerjee et al , 2016aBansal et al 2017Bansal et al , 2018. A recent review indicates unusually high abundance of glauconite during the Early Cretaceous, Late Cretaceous and Eocene, accounting for roughly 11 %, 18 % and 12 % of a total record of 453 glauconite occurrences respectively (Banerjee et al 2016b).…”

The formation of authigenic deposits during Paleogene warm climatic intervals: a review

“…1, 7). Several factors determine the formation of glauconite, including depositional conditions, sedimentation rate, seawater temperature, availability of iron and potassium (Odin and Matter 1981;Amorosi 1995Amorosi , 1997Amorosi , 2011Amorosi , 2012Amorosi and Centineo 1997;El Albani et al 2005;Amorosi et al 2007Amorosi et al , 2012Meunier and El Albani 2007;Banerjee et al 2016aBanerjee et al , 2016bMandal et al 2020). The following section discusses the influence of the controlling factors in the formation of authigenic glauconite during the Paleogene.…”