Naresh Chandra Pant
Articles written in Journal of Earth System Science
Volume 122 Issue 3 June 2013 pp 677-698
Preeti Singh Ashima Saikia Naresh Chandra Pant Pramod Kumar Verma
The present study is on the Ultra High Pressure Metamorphic rocks of the Tso Morari Crystalline Complex of the northwestern Himalayas. Five different mineral associations representative of five stages of P–T (pressure–temperature) evolution of these rocks have been established based on metamorphic textures and mineral chemistry. The pre-UHP metamorphic association 1 of Na-Ca-amphibole + epidote ± paragonite ± rutile ± magnetite with T–P of ∼500° C and 10 kbar. This is followed by UHP metamorphic regime marked by association 2 and association 3. Association 2 (Fe< Mg< Ca-garnet + omphacite + coesite + phengite + rutile ± ilmenite) marks the peak metamorphic conditions of atleast 33 kbar and ∼750° C. Association 3 (Fe< Mg< Ca-garnet + Na-Ca amphibole + phengite ± paragonite ± calcite ± ilmenite ± titanite) yields a P–T condition of ∼28 kbar and 700°C. The post-UHP metamorphic regime is defined by associations 4 and 5. Association 4 (Fe< Ca< Mg-garnet + Ca-amphibole + plagioclase (An05) + biotite + epidote ± phengite yields a P–T estimate of ∼14 kbar and 800°C) and association 5 (Chlorite + plagioclase (An0.5) + quartz + phengite + Ca- amphibole ± epidote ± biotite ± rutile ± titanite ± ilmenite) yields a P–T value of ∼7 kbar and 350°C.
Volume 130 All articles Published: 19 November 2021 Article ID 0234 Research article
NILANJANA SORCAR SNEHA MUKHERJEE NARESH CHANDRA PANT J AMAL DEV N NISHANTH
Major and trace element analyses of monazite by electron probe microanalyzer (EPMA) are routinely
carried out for several decades. U–Th–total Pb method of monazite dating is currently considered as a reliable and
acceptable tool to decipher the time of geological events. The purpose of the present study isto establish the
quantification conditions of monazite chronology using SXFive tactis EPMA, recently installed at the National
Centre for Earth Science Studies, Thiruvananthapuram, India. Consistency in the chemical-chronological data of
the monazites starting from the chronologically well-constrained Maocyr monazite data followed by the analysis
of monazite from the garnet-cordierite gneiss of the Kerala Khondalite Belt confirms the reliability of the
NCESS-EPMA facility for the U–Th–total Pb chemical age dating of monazite. By applying the same analytical
setup of chemical dating, the monazites from metapelites of Madurai Block of Southern Granulite Terrain, India
yield two peak ages in probability density diagram of
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