TY  - SER
AU  - Simón, J.L. 
AU  - Soriano, A. 
TI  - Diapiric deformations in the quaternary deposits of the Central Ebro Basin, Spain
KW  - Aragon Spain
KW  - Ebro basin - Europe
KW  - Field studies
KW  - Iberian peninsula
KW  - Quaternary
KW  - Saragossa Spain
KW  - Structural geology
N2  - From a study of 24 outcrops in Neogene and Quaternary deposits of the central Ebro Basin, a number of diapiric deformations have been recognized, two principal types being differentiated: domal or pillow structures, and piercement or intrusive structures. The former are incipient diapirs of gypsum. Piercing structures have reverse faulted contacts not caused by halokinesis; here Neogene marls are the active plastic material, contrasting with the competent behaviour of gypsum. These intrusive structures are viscous diapirs which easily pierce the non-consolidated, low strength Quaternary gravel overburden and submit it to a horizontal compressive stress. As a consequence, reverse faults and flexures develop in it. Generally normal faults and tension cracks do not appear. Underlying gypsum beds are frequently pulled up into diapirs and they constitute the structural core.

Density contrast and conditions for plastic flow exist at the marl–gravel boundary. It seems to have been specially common at the time of Quaternary fluvial sedimentation, so that much deformation is synsedimentary. Diapiric phenomena have been very active during early to middle Pleistocene time, becoming weaker afterwards
ER  -