Paleointensity of the Earth’s magnetic Beld at 􏰊 117 Ma determined from the Rajmahal and Sylhet Trap Basalts, India

We present here the paleointensity results of basalt samples from Rajmahal and Sylhet Traps of eastern India to know the strength of the earth’s magnetic field during the early Cretaceous from these locations. The modified version of the Thellier–Thellier paleointensity method of, in field-zero field-zero field-in field (IZZI) protocol and systematic partial thermoremanent magnetization (pTRM) checks were used for the paleointensity determination. Rock magnetic investigations on these rocks indicate ‘magnetite’ is the main remanence carrier with single domain (SD) to pseudosingle domain (PSD) nature. The samples have yielded low paleofield intensities between 6.97 ± 2.21 and 23.47 ± 2.08 lT (mean 17.20 ± 1.89 lT). The corresponding virtual dipole moment (VDM) ranges from 1.16 to 4.17 9 1022 Am2 (mean 2.93 9 1022 Am2) which is approximated as to 30% of the present-day Beld strength (8 9 1022 Am2). Our new results compared with published paleointensities from these basalts as well as rocks of Cretaceous normal superchron (CNS) time around the globe are in good agreement.


Citation: M R KAPAWAR and VENKATESHWARLU MAMILLA , 2021. J. Earth Syst. Sci. (2021)130:154, external link