The oldest paleomagnetic anomalies in the Arabean Sea

A detailed chronology of the north Arabean seabottom is restored. Evidences of linear sublatitudial anomalies in the magnetic-field north of 20 degree s N are obtained and identified as paleomagnetic anomalies (together with r elated subchrons) C29-C32n.2n. We can not exclude a possibility of alternat e dating of paleomagnetic anomalies in spreading cell 4. In the latter case anomaly 32n.2n can not have a spreading nature and may reflect the contine nt-ocean boundary (OCB anomaly). The presented identification of magnetic a nomalies does not contradict available geological-geophysical materials (in cluding the materials of Deep Sea Drilling) in the North-Western part of th e Indian ocean and well known paleogeodynamic reconstructions. From the pai nt of view of the presented analysis the beginning of spreading can be date d by the time of subchron C31n (67.737-68.737 my) or possibily, C32n.2n (71 .6 my). The evidences of oceanic nature:for the Lakshmi ridge, formerly kno wn as continental fragment, are presented.