IVORY-COAST MICROTEKTITES AND GEOMAGNETIC REVERSALS

The reported association of the Ivory Coast microtektite occurrence with the onset of the Jaramillo normal polarity subchron has given support to the notion that impact events can give rise to geomagnetic reversals. We re‐evaluate the paleomagnetic stratigraphy of two critical deep‐sea sediment cores bearing Ivory Coast microtektites (K9‐57 and V27‐239) and show that this event likely occurred during the Jaramillo subchron approximately 30 kY after its onset and 40 kY before its termination. This new result thus argues against any causal relationship between the Ivory Coast tektite‐producing event and a geomagnetic polarity reversal. © 1990 by the Chinese Geophysical Society