The Cretaceous Normal Polarity Superchron is an outlier in the distribution of geomagnetic polarity chron lengths. During the Superchron the field was of apparent constant normal polarity for approximately 37 million years. This has led some authors to propose the geomagnetic field has two fundamental states: one in which the field reverses and one in which the reversal process ceases. Against these well-founded inferences is the mounting evidence for one or more brief (less than 100 kyr) intervals of reversed polarity, called reversal events, during the Superchron. The evidence for reversal events includes recent paleomagnetic data from the Rajmahal Hills of eastern India. However, it is unclear from the available data whether reversals actually occurred. In addition, the reported directions could record a geomagnetic excursion rather than a true field reversal. The proposed work addresses these questions through a field program in eastern India coupled with laboratory studies, including paleomagnetic, rock magnetic and radiometric age analyses. If confirmed, the reversal event in the Rajmahal lavas represents a fundamental conflict between model predictions and observations with implications for the generation of the geomagnetic field.
