Katie Lucas HBSc thesis abstract

Thesis Title: 
Paleomagnetism and Magnetic Fabrics of the Akamas Ophiolite as Compared to the Troodos Ophiolite, Cyprus

Paleomagnetism and magnetic fabrics were determined for 2903 samples of the Akamas ophiolite, for comparison with the Troodos ophiolite, both located on the island of Cyprus.  The relationship between the ophiolites is inferred from the anisotropy of magnetic susceptibility (AMS), natural remnant magnetism (NRM) combined with low temperature demagnetization (LTD) and thermal demagnetization (TD), and paleopole studies.

From these data, it is determined that the ophiolites are of similar origin but produced at different times and locations.  Akamas is a Triassic slow spreading center from a rifted continental margin and Troodos is a Cretaceous slow spreading center from a suprasubduction zone.  The magnetic fabric from both Akamas and Troodos is that of an S-fabric, with a slightly continuity into the L-fabric field.  The AMS data for both ophiolites dips east-south-east, with two distinct regions of foliation, one steep and one shallow.  Principle component analysis determined two distinct magnetic polarities, both exhibiting a mild tectonic smearing.  The paleopole for these data points is determined to be 73 N, 95 W and 75 N, 85 E in a normal field and 27 S, 45 E and 10 S, 20 E in a reversed field.  The mean declination and inclination for these data is 159/-62 and 210/-47 in a normal field and 159/62 and 210/47 in a reversed field (a95 = 10.6).  These data are plotted in the apparent polar wander path for Cyprus determined by Borradaile and Gauthier (in prep.).  It is concluded that the difference in magnetic polarity seen in the PCA analysis of the NRM (LTD, TD) results represent a reversal of the Earth's magnetic field.  This reversal is confirmed by magnetostratigraphy comparisons with Upper Triassic data.  The paleopole data also indicates a ~120° anticlockwise rotation of the Akamas ophiolite and the Mamonia terrain, prior to the documented 90° anticlockwise rotation of Cyprus.