Pedogenic modification and structure evolution in palustrine facies as exemplified by the Bembridge Limestone (Late Eocene) of the Isle of Wight, southern England

Discriminating between tectonism and climate signatures in palustrine deposits: Lessons from the Miocene of the Teruel Graben, NE Spain

“…12) reveals its similarity to that observed at present in different areas of Las Tablas de Oaimiel (Fig. 13) and to that described by Armenteros and Daley (1998 ) for the Late Eocene of the Isle of Wight. This palaeogeography shows relative homogeneity in sedimentary and pedogenic processes operating across the entire study area, which probably reflects the infill of the lake accommodation space and subsequent exposure of wide areas (Fig.…”

“…Coated grains are a typical feature of many lacustrine/palustrine deposits (Alonso-Zarza et al., 1992;Armenteros and Daley, 1998) as well as of calcretes (Calvet and Julia, 1983). In palustrine settings, the formation of coated grains is considered to be the result of both inorganic and organic processes.…”

“…In palustrine settings, the formation of coated grains is considered to be the result of both inorganic and organic processes. Inorganic processes such as wetting and drying cycles are the main cause of desiccation and brecciation of lacustrine primary deposits and thus of the isolation of micrite fragments from the whole deposit to form isolated micritic fragments or nodules (Freytet and Plaziat, 1982;Armenteros and Daley, 1998). Roots and microorganisms can also contribute to the fragmentation of lacustrine deposits, as observed in the Miocene of the Madrid Basin (Alonso-Zarza et al., 1992 ).…”

“…Their formation is the combined effect of mechanical fragmentation either by desiccation or by root penetration of the primary deposits leading to gradual separation or individualization of carbonate grains (grainification) and then to their coating (Alonso-arza etal., 1992;Armenteros and Daley, 1998 ). Later reworking, organic activity, internal sedimentation, and vadose and phreatic cementation produced a complex limestone fabric (AlonsoZarza et al, 1992) of a compound ooidal microstructure (Armenteros and Daley, 1998) or syngenetic grainstone (Mazzullo and Birdwell, 1989), which reflects the most intense alteration of the initial deposit. However, these modifications The most outstanding feature is that the micro-karst surface (see description above) ( Fig.…”

Paleoclimatic implications (Late Cretaceous–Paleogene) from micromorphology of calcretes, palustrine limestones and silcretes, southern Paraná Basin, Uruguay

“…During the last decades, several types of duricrust have been the subject of many studies, including calcretes (Semeniuk and Meagher, 1981;Tandon and Narayan, 1981;Arakel, 1982;Wright, 1982;Goudie, 1983;Braithwaite, 1983;Esteban and Klappa, 1983;Machette, 1985;Wright, 1990;Wright and Tucker, 1991;Mack and James, 1994;Wright and Platt, 1995;Pimentel et al, 1996;Mack et al, 2000;Khadkikar et al, 2000;Alonso Zarza, 2003;Huerta and Armenteros, 2005;Kalaf, 2007, among others), silcretes (Thiry and Millot, 1986;Thiry and Milnes, 1991;Thiry, 1999;Ullyott and Nash, 2006, among others) and palustrine limestones (Armenteros et al, 1997;Armenteros and Daley, 1998;Tandon and Andrews, 2001;Freytenet and Verrecchia, 2002;Alonso Zarza, 2003;Huerta and Armenteros, 2005; among others). They are common throughout the stratigraphic record in continental basins but particularly abundant in some intervals of Mesozoic and Cenozoic stratigraphic intervals.…”