New Palaeomagnetic Data from the Main and Upper Zones of the Bushveld Complex

摘要

The Bushveld Complex (BC) has been the subject of many palaeomagnetic investigations since 1959. Despite these studies, systematic inconstancies have been found between the palaeomagnetic findings and well constrained ages determined for the Bushveld Complex. One concern is the large spread in pole positions previously determined for the different zones of the BC. This has been interpreted in prior studies to indicate that the Bushveld was emplaced and cooled below the Curie temperature of magnetite over a time span of 50 Ma. This inconsistency has prompted the current re-investigation of the palaeomagnetic results. New palaeomagnetic data collected in the Main and Upper zones of the Eastern and Western limbs of the BC, yielded palaeomagnetic poles that eliminated the spread in the apparent polar wander path. This observation is in agreement with precise age data, constraining the time period of emplacement of the BC. Fold tests applied to each zone yielded statistically positive results supporting a primary magnetic signature and indicate that the complex was intruded in a near horizontal position.