• Manash Pratim Gogoi

      Articles written in Journal of Earth System Science

    • Analyses of fold profiles by changing weight parameters of NURB curves

      Manash Pratim Gogoi Soumyajit Mukherjee Tapos K Goswami

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      Analyses of Non-Uniform Rational B-spline (NURB) curve by varying weights at its nodal points and projection ratio produce several kinetically plausible symmetric and asymmetric fold morphologies in 2D promptly and efficiently with varied overall geometries, curvature of limbs, sharpness/bluntness of hinges, extent of hinge zone, tightness/interlimb angles, etc. Some of these folds are new geometries what other approaches, such as those with Bézier curve, did not produce so far. Natural fold profiles can be matched with NURB curves from photographs.

    • Petrography and whole-rock geochemistry of Oligocene Barail Sandstones of Surma basin: Implications for tectono-provenance and paleoclimatic condition


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      The Oligocene Barail Sandstones of Surma basin from parts of Champhai District of Mizoram, northeast India has been studied for their tectono-provenance setting using petrography and geochemistry. The studied sandstones are poor to moderately sorted, subarkosic to sub-litharenite and show dominance of quartz (avg. 54.46%) followed by feldspars (avg. 7.22%), rock fragments (avg. 4.98%), mica (avg. 5.89%), matrix (avg. 14.47%) and cement (avg. 12.98%). Dominance of polycrystalline and undulatory monocrystalline quartz indicates contribution from medium grade metamorphic sources, primarily of granite gneisses. High concentration of SiO$_{2}$ with moderate to low concentration of Al$_{2}$O$_{3}$, Fe$_{2}$O$_{3}$, MgO, Na$_{2}$O and K$_{2}$O resembles the composition of upper continental crust. Moreover, moderate to high concentration of Th and V, depleted value of Ni along with TiO$_{2}$/Zr suggests derivation of sediments from felsic sources. The ratios of Eu/Eu* (avg. 0.63) and La$_{\rm {N}}$/Lu$_{\rm{N}}$ bears resemblance with the upper continental crust. Overall analyses show that the sediments were derived from the felsic terrain of neighbouring orogens probably represented by granite-gneisses and have undergone a moderate degree of weathering (avg. values of CIA: 70.20, CIW: 81.03, PIA: 77.63, WIP: 38.45, ICV: 1.06, I$_{\rm{w}}$ = 2) in a semi-humid to humid climatic conditions [Q$_{\rm{p}}$ /(F + RF):Q$_{\rm{t}}$ /(F + RF) = 0.20].

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