RT Journal Article
T1 Circulación de fluidos en fracturas en el miembro superior de la Fm. Armàncies (Eoceno, Pirineo oriental)
T1 Fluid history through fractures in the upper part of the Armàncies Formation (Eocene, Pyrenean Basin)
A1 Caja, Miguel Ángel
A1 Permanyer, Albert
A1 Marfil Pérez, Rafaela
A1 Martín Crespo, Tomás
AB The presence of oil shows associated with fractures provides a significant opportunity to unravel the type,origin and evolution of fluids involved in fractures cementation and their relationship to oil migration. Twostages of calcite cement were distinguished in the fractures of the Eocene Armàncies platform carbonates:i) C1 calcite cement is characterised by fence-like crystals with abundant twin planes and inclusions, dullred luminescence, relative high Fe and Mg content and d18O values ranging from -6.2‰ to -4.8‰ VPDB.C1 precipitated from meteoric fluids during burial in reducing conditions. ii) C2 calcite cement ischaracterised by blocky clean crystals showing dark brown to red luminescence alternating with brightyellow bands, relatively low Fe and Mg content, and d18O values from -9.6‰ to -8.9‰ VPDB. C2 containsaqueous and hydrocarbon fluid inclusions with mode homogenisation temperatures of 120ºC. This cementprecipitated from a fluid at higher temperature and relatively less reducing conditions than C1. Porosityassociated with C2 is filled with liquid oil that reached 115ºC. Therefore, free oil and fluid inclusions oilcome from the same migration pulse. Oil migration timing was synchronous with C2 and continued whencalcite cementation completed
PB Sociedad Geológica de España
YR 2005
FD 2005
LK http://hdl.handle.net/10272/8650
UL http://hdl.handle.net/10272/8650
LA spa
DS Repositorio Institucional de la Universidad de Huelva
RD 30 may 2026