As the basalt cools and solidifies it will take on the magnetic orientation of the Earth at that time. Therefore there will be no difference between that of land and ocean flood basalts. However, the strength of the Earth's magnetic field is not uniform and so the actual remanence will vary with the geographical location of the basalt, e.g. the magnetic dip increases with latitude. Moreover, the Earth's magnetic field is not uniform so the cooling lava will adopt any anomalies at the location at which it is formed.

@Alastair Bain McDonald sir,, actually my question is that since ocean floor is already basalt but when flood basalt is out pored on ocean floor there will be two layer of basalt then both layer of basalt will show combined effect of magnetic anomaly then how does this anomaly varies with that of only ocean floor ??

Hi Pankar,

Am I correct in thinking you are asking about the basalts laid down by the Reunion hot spot? If so then those basalts will be laid down on top of the already solidified Indian Ocean basalts which will have remanent magnetism from the time they solidified. The Reunion basalts will take up the magnetism that fits with the time when they solidify. The remanent magnetism from the Indian ocean basalts is so weak that its effect on the Reunion basalts will be negligible.

HTH,

Cheers, Alastair.

@Alastair Bain McDonald,,, thank you sir