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Distinguishing the effect of diapir growth on magnetic fabrics of syn‐diapiric overburden rocks: Basque–Cantabrian basin, Northern Spain
Author(s) -
Soto Ruth,
Beamud Elisabet,
Roca Eduard,
Carola Eloi,
Almar Ylenia
Publication year - 2017
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/ter.12262
Subject(s) - diapir , lineation , geology , compression (physics) , sedimentary depositional environment , geochemistry , overburden , structural basin , paleontology , geomorphology , tectonics , materials science , composite material
Abstract An analysis of Anisotropy of Magnetic Susceptibility was done on Aptian–Albian sediments from the Basque–Cantabrian basin. Samples were collected from 39 sites in the halokinetic sequences of the Bakio, Bermeo, Guernica and Mungia diapirs; 28 sites were sampled close to diapirs, and 11 sites were far from the diapir edges. The magnetic foliation is parallel to bedding, suggesting it reflects depositional and compaction processes, whereas the orientation of magnetic lineation varies. Far from the diapir edges, the magnetic lineation is interpreted as being related to the regional Pyrenean compression. Close to diapir edges, the observed behaviour shows that diapirs, predominantly formed by rigid ophites, have acted as buttresses, with shadow areas at their northern faces being protected from the Pyrenean compression. The high sensitivity of AMS makes it a very useful tool to distinguish deformation in halokinetic sequences related to diapir growth from that related to subsequent compression.