A geochemical study on the Lansdowne granite and granite gneiss, Garhwal Lesser Himalaya, Uttarakhand (India)

The Lansdowne klippe in the Lesser Himalaya is a thrust-plunging syncline comprising Precambrian granite and granite gneiss, prominently exposed around Jaiharikhal-Lansdowne in Garhwal region.The study area consists metasedimentary rocks, quartzose-phyllite, mylonite/phyllonite, granitic and augen gneisses.Granites exhibit medium-coarse, hypidiomorphic, and porphyritic textures with minerals Pl-Kfs-Qtz-Bt-Mus-Tour-Mag-Ap-Zr-Ep.Granite gneisses exhibit a mineral composition similar to that of granite, but with a well-developed foliation plane.Near fault zones, mylonitic textures with quartz ribbons and sericite occurrences, indicate NW-SE shearing.Textural features (porphyritic, perthitic) and geochemical characteristics (alkalic-ferroan, peraluminous), suggest slow cooling from a direct magmatic origin within syn-collisional to post-orogenic settings.