DOI: 10.5176/2251-3361_GEOS12.83
Authors: Animesh Mandal, W. K. Mohanty, S. P. Sharma
Abstract: South Purulia Shear Zone (SPSZ) within the
Singhbhum craton of East Indian Shield has been identified with
similar geometrical shape and mineralization; like famous
copper-uranium belt of Singhbhum Shear Zone (SSZ). This
increases the possibility of the existence of uranium
mineralization in SPSZ. The mineralization of this region is
mainly structural guided and hydrothermally generated. Thus,
an integrated gravity-magnetic study was performed around
Manbazar-Kutni area across SPSZ to identify the subsurface
structures and probable correlation with mineralization. The
first degree trend surface separated residual gravity as well as
the Bouguer gravity and magnetic anomaly maps depicted the
ESE-WNW trending SPSZ on the SW part of the area. 2D
forward gravity modeling across the shear zone clearly reveals
the presence of nearly 12 km wide low density zone (most likely
sheared granite and mineralization zone) extending up to Chepua
village under a thin cover of granitic schist of CGGC. Some cross
cutting faults are also identified within the study area. The
presently observed negative gravity and moderately high
magnetic anomalies around Dighi, Chepua villages are also
characterized by medium to high hydro-uranium anomaly from
earlier hydro-uranium anomaly studies. Therefore, the negative
gravity and moderate positive magnetic anomaly zone is
concluded to be hydrothermally altered brecciated zone and
these are the possible uranium mineralized zone. Since surface
signature of nuclear radiation has not been observed, uranium
mineralized zone could be at a large depth. Thus, the study
demonstrates the effectiveness of gravity-magnetic method for
subsurface structural investigation and to identify the
mineralization zones in conjunction with other know
mineralization indication.
Keywords: SPSZ, Gravity, Magnetic, 2D modeling, hydrouranium
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