%0 Journal Article
%A Fernández Barrenechea, José María
%A Rodas, Magdalena
%A Frey, Martín
%A Alonso Azcárate, Jacinto
%A Mas Mayoral, José Ramón
%T Clay diagenesis and low-grademetamorphism of Tithonian and Berriasiansediments in the Cameros Basin (Spain)
%D 2011
%@ 0009-8558
%U https://hdl.handle.net/20.500.14352/42464
%X The clay mineral assemblages of the Tithonian and Berriasian sediments (Tera andOncala Groups) in the eastern part of the Cameros basin are investigated at seven localities. Thelowest-grade assemblage, located on the southern border of the basin, contains calcite + quartz +hematite + kaolinite + mixed-layer illite-smectite (R = 1, 6585% illite layers) + discrete illite (IC= 0.50.65D82y). Systematic increases in the illite and chlorite crystallinities suggest increasingmetamorphic grade from the northwest part of the basin to the southeast. This trend does not followthe pattern previously described for the overlying late Berriasian–early Aptian sediments (Urbio´n andEnciso Groups), which exhibit a higher metamorphic grade. This may result from local variations insedimentary facies, as well as the circulation of hot migratory fluids. Tertiary compression occurringlong after the main metamorphic event is considered to be responsible for the enhanced illite andchlorite crystallinities measured in the SE extreme of the basin.
%~