Magnetostratigraphy of a Part of Middle Bhuban Sequence (Surma Group), Aizawl, Mizoram

A 560 m thick rock succession of Middle Bhuban Formation (Surma Group) exposed between Bawngkawn and Durtlang, Aizawl, Mizoram has been studied for its magnetostratigraphic attributes. A total of 7 normal and 7 reverse magneto-Zones have been delineated in this section. The GPTS correlated ages of this section lie between -21.77 Ma (at the base) to ∼15.16 Ma (at the top) with a total duration of ∼6.6 Ma. The GPTS event C6n occurring at the stratigraphic level between 146 m to 266 m may be considered for basin wide correlation as it is the longest normal event that has been recorded with greater confidence i. e. better alpha- 95. The average sediment accumulation rate (SAR) estimated for this section is 8.48 cm/Ka. Overall the SAR is higher in the lower part of the section with a spike of 26.8 cm/Ka at <21 Ma. The decrease in SAR to 2.1 cm/Ka at around 18 Ma in the upper part of the section may be investigated for possible hiatus.