| Abstract: | During folding of the Scaglia Rossa limestone in Umbria, Italy, deformation was mainly accommodated by pressure solution cleavage. Fossils between the cleavage planes appear visibly undeformed, yet the limestone possesses a weak magnetic fabric. The maximum and intermediate principal axes of the magnetic anisotropy ellipsoid define a distinct magnetic foliation plane within which a weak concentration of the maximum axes forms a magnetic lineation. Neither of these features is of sedimentary origin. Results from a slumped outcrop, where bedding and a cleavage induced by overburden compaction have different attitudes, show that the magnetic foliation is caused by the compaction. Comparisons with field-derived structural data suggest that the magnetic lineation was produced tectonically during deformation of the Apennine fold belt. |
