TY - JOUR
T1 - From early contraction to post-folding fluid evolution in the frontal part of the bóixols thrust sheet (Southern Pyrenees) as revealed by the texture and geochemistry of calcite cements
AU - Nardini, Nicholas
AU - Muñoz-López, Daniel
AU - Cruset, David
AU - Cantarero, Irene
AU - Martín-Martín, Juan Diego
AU - Benedicto, Antonio
AU - Gomez-Rivas, Enrique
AU - John, Cédric M.
AU - Travé, Anna
PY - 2019/2/1
Y1 - 2019/2/1
N2 - © 2019 by the authors. Licensee MDPI, Basel, Switzerland. Structural, petrological and geochemical (δ 13 C, δ 18 O, clumped isotopes, 87 Sr/ 86 Sr and ICP-MS) analyses of fracture-related calcite cements and host rocks are used to establish a fluid-flow evolution model for the frontal part of the Bóixols thrust sheet (Southern Pyrenees). Five fracture events associated with the growth of the thrust-related Bóixols anticline and Coll de Nargó syncline during the Alpine orogeny are distinguished. These fractures were cemented with four generations of calcite cements, revealing that such structures allowed the migration of different marine and meteoric fluids through time. During the early contraction stage, Lower Cretaceous seawater circulated and precipitated calcite cement Cc1, whereas during the main folding stage, the system opened to meteoric waters, which mixed with the connate seawater and precipitated calcite cement Cc2. Afterwards, during the post-folding stages, connate evaporated marine fluids circulated through newly formed NW-SE and NE-SW conjugate fractures and later through strike-slip faults and precipitated calcite cements Cc3 and Cc4. The overall paragenetic sequence reveals the progressive dewatering of Cretaceous marine host sediments during progressive burial, deformation and fold tightening and the input of meteoric waters only during the main folding stage. This study illustrates the changes of fracture systems and the associated fluid-flow regimes during the evolution of fault-associated folds during orogenic growth.
AB - © 2019 by the authors. Licensee MDPI, Basel, Switzerland. Structural, petrological and geochemical (δ 13 C, δ 18 O, clumped isotopes, 87 Sr/ 86 Sr and ICP-MS) analyses of fracture-related calcite cements and host rocks are used to establish a fluid-flow evolution model for the frontal part of the Bóixols thrust sheet (Southern Pyrenees). Five fracture events associated with the growth of the thrust-related Bóixols anticline and Coll de Nargó syncline during the Alpine orogeny are distinguished. These fractures were cemented with four generations of calcite cements, revealing that such structures allowed the migration of different marine and meteoric fluids through time. During the early contraction stage, Lower Cretaceous seawater circulated and precipitated calcite cement Cc1, whereas during the main folding stage, the system opened to meteoric waters, which mixed with the connate seawater and precipitated calcite cement Cc2. Afterwards, during the post-folding stages, connate evaporated marine fluids circulated through newly formed NW-SE and NE-SW conjugate fractures and later through strike-slip faults and precipitated calcite cements Cc3 and Cc4. The overall paragenetic sequence reveals the progressive dewatering of Cretaceous marine host sediments during progressive burial, deformation and fold tightening and the input of meteoric waters only during the main folding stage. This study illustrates the changes of fracture systems and the associated fluid-flow regimes during the evolution of fault-associated folds during orogenic growth.
KW - Bóixols thrust sheet
KW - Fractures
KW - Geochemistry of calcite cements
KW - Meteoric and marine fluids
KW - Southern Pyrenees
U2 - 10.3390/min9020117
DO - 10.3390/min9020117
M3 - Article
VL - 9
JO - Minerals
JF - Minerals
SN - 2075-163X
M1 - 117
ER -