JURASSIC TECTONIC HISTORY OF THE OTAGO SCHIST, NEW-ZEALAND

A regional reanalysis of the Otago Schist shows that ductile mesoscopic structures can be interpreted as elements of a single, progressive, heterogeneous, noncoaxial, Jurassic deformation related to juxtaposition of the Caples and Torlesse terranes. Stretching lineations are parallel, oblique, and perpendicular to the orogen in various parts of Otago, but changes in trend are generally unrelated to the terrane boundary. Structural geometry and rare shear criteria indicate that the Caples terrane overthrust the Torlesse terrane from the south and west, but precise transport directions are not known, being model-dependent. Macroscopic recumbent folds may be present in the schist, but mainly in the form of partially developed nappe structures truncated by zones of retransposed foliation and/or high strain.