Calcite fabrics in the hinge zones of experimentally folded single layers of marble and limestone

Abstract

The preferred orientations of poles to (0006) and (1014) planes in calcite have been studied in the inner and outer arcs of experimentally produced single-layer buckle folds in Carrara marble and Solnhofen limestone. The textures produced in the medium-grained marble differ from that of the fine-grained limestone. Further, the pole figures from the inner fold arcs are characterized by a general orthorhombic symmetry and a strong preferred orientation of the crystallographic fabric elements, whereas that from the outer fold arcs generally exhibits a triclinic symmetry and a weak preferred orientation. The difference in the pole figures in medium-grained marble and fine-grained limestone is attributed to the mechanism of internal deformation in calcite. The orthorhombic symmetry of the pole figures from the inner fold arc suggests a coaxial strain history in this zone, whereas the triclinic symmetry of the fabric diagrams from the outer fold arcs is attributed to a non-coaxial strain history. © 1989.