Abstract:
The North Singhbhum Mobile Belt (NSMB) is a 200 km long, curved Proterozoic fold–
thrust belt that skirts the northern margin of the Archean Singhbhum Craton of NE India. The
Singhbhum Shear Zone (SSZ) developed between the Dhanjori and Chaibasa formations near the
southern margin of the NSMB and represents an important Cu-U-P metallotect. A SHRIMP U–Pb
zircon date of 1861±6 Ma, obtained for the syn- to post-kinematic Arkasani Granophyre that has
intruded the SSZ, provides a minimum age for the prolonged tectonic activity and mineralization along
the SSZ and for the time of closure of the Chaibasa and Dhanjori sub-basins. The Dalma Volcanic
Belt, a submarine rift-related bimodal mafic-felsic volcanic suite, forms the spine of the NSMB. A
SHRIMP U–Pb zircon igneous crystallization date of 1631±6 Ma was obtained for an unfoliated
felsic volcanic rock from the base of the Dalma volcanic sequence. These new findings suggest that
the different sub-basins in the NSMB evolved diachronously under contrasting tectonic environments
and were juxtaposed during a later orogenic movement.
