Journal - Early Proterozoic granite of the Taplejung Window, far eastern Lesser Nepal Himalaya

Early Proterozoic granite of the Taplejung Window, far eastern Lesser Nepal Himalaya

 B. N. Upreti. S. M. Rai and D. R. Koirala

Department of Geology, Tribhuvan University, Tri-Chandra Campus,Ghantaghar, Kathmandu, Nepal

H. Sakai

Department of Earth Sciences, Kyushu University, Ropponmatsu, Fukuoka, 810-8560, Japan

Y. Takigami

Kanto Gakuen University, Ohta-shi, Gunma, 373-8515, Japan

Jour. Nepal Geol. Soc., 2003, Vol. 28, 9–18


Abstract

The Lesser Himalayan Sequence of the Taplejung Window in the far eastern Nepal Himalaya can be divided into Taplejung Formation, Mitlung Augen Gneiss and Linkhim Schist (from bottom to top respectively). The window is a large domal shaped anticline plunging to the east.

 

Two-mica granite bodies (Amarpur Granite, Kabeli Khola Granite and Tamor River Granite) have intruded the metasediments of Taplejung Formation. The granite bodies are discordant to subconcordant in relation to the country rocks. Quartz, alkali feldspar, plagioclase, muscovite, biotite and tourmaline are the main constituent minerals of the granite. Generally, the core of granite bodies is undeformed, where as the marginal part is gneissfied with S-C mylonitic texture showing the top to south sense of shear. This sense of shear is related to the movement along the Main Central Thrust (MCT). All the samples from the granitic bodies fall under the granite field in the normative quartz-alkali feldspar-plagioclase (QAP) triangular diagram. The mineral composition shows that the granite is peraluminous in nature. The Kabeli Khola Granite has yielded a 40Ar/39Ar muscovite age older than 1.6 Ga indicating its magmatic age. The granites of the study area can also be correlated with the 1.8 Ga Ulleri type augen gneiss of central Nepal.

Member Login
NEWS AND EVENTS
  • Jul
    08

    Academic and professional development Sub Committee of the Nepal Geological Society and Nepal Geological Students’ Society in collaboration with Central Department of Geology has organized a training and interaction program entitled “Mining and Engineering Geology in field” on 23rd  Asadh 2075 at the conference hall of the Central Department of Geology, Kirtipur.

  • May
    21

    Nepal Geological Society has organized a press meeting on the memory of 2015 Gorkha Earthquake on 2075/1/12 at the conference hall of Department of Irrigation, Jawalakhel

Activities and Information

Activities of 17th and 18th Executive Committee
Nepal Geological Society
P.O.Box No. 231
Kathmandu, Nepal
FREEPHONE: +977-01-4437874
Email: info@ngs.org.np