Plate kinematics beyond geomagnetic reversals: the South Atlantic Ocean during the Cretaceous superchron Academic Article uri icon

abstract

  • Globally correlatable marine magnetic anomalies record past polarity reversals and changes in the strength of the dipolar geomagnetic field. Traditionally, plate reconstruction models rely on reversals-related anomalies leading to a well-known major temporal gap and tectonic ambiguities in the existing kinematic models for the Cretaceous normal superchron (120.6-83.5 Ma), a long period when no polarity reversal took place. Recent findings on the behavior of the geomagnetic field during the superchron (Granot et al., 2012) provide new time markers that may be used to define internal isochrons within the Quiet Zones. We examined the magnetic anomalies above the slow to intermediate spreading South Atlantic Quiet Zones to build a new kinematic model for the opening of the basin. We calculated six sets of finite rotation parameters for Anomalies M4 (126.5 Ma), M0 (120.6 Ma), Q2 (~ 108 …

publication date

  • December 1, 2013