Juyal, N., Sundriyal, Y.P., Rana, N., Chaudhary, S., Singhvi, A.K. 2010. Late Quaternary fluvial aggradation and incision in the monsoon-dominated Alaknanda valley, Central Himalaya, Uttrakhand, India. J. Quaternary Sci., Vol. 25 pp. 1293–1304. ISSN 0267-8179.
Late Quaternary fluvial aggradation and incision in the monsoon-dominated Alaknanda valley, Central Himalaya, Uttrakhand, India†
Article first published online: 23 NOV 2010
Copyright © 2010 John Wiley & Sons, Ltd.
Journal of Quaternary Science
Volume 25, Issue 8, pages 1293–1304, December 2010
How to Cite
juyal, N., Sundriyal, Y., rana, N., chaudhary, S. and Singhvi, A. k. (2010), Late Quaternary fluvial aggradation and incision in the monsoon-dominated Alaknanda valley, Central Himalaya, Uttrakhand, India. J. Quaternary Sci., 25: 1293–1304. doi: 10.1002/jqs.1413
- Issue published online: 25 NOV 2010
- Article first published online: 23 NOV 2010
- Manuscript Accepted: 30 MAR 2010
- Manuscript Revised: 26 MAR 2010
- Manuscript Received: 24 OCT 2009
- DST. Grant Number: SR/S4/ES-139/2005
- late Quaternary;
- optical dating;
- Central Himalaya
The present study aims to explain the spatial and temporal variability in phases of aggradation/incision in response to changes in climate and seismicity during the late Quaternary in the Alaknanda River valley (a major tributary of the river Ganges or Ganga). Geomorphology, stratigraphy and optical dating of the fluvial sediment reveal that the oldest fluvial landforms preserved in the south of the Main Central Thrust are debris flow terraces developed during the early part of pluvial Marine Isotopic Stage 3. Following this, a period of accelerated incision/erosion owing to an increase in uplift rate and more intense rainfall occurred. In the Lesser Himalaya, three phases of valley fill aggradation around 26 ± 3 ka, 18 ± 2 ka and 15 ± 1 ka and 8 ± 1 ka occurred in response to changes in monsoon intensity and sediment flux. The last phase was regionally extensive and corresponds to a strengthening of the early Holocene Indian Summer Monsoon. A gradual decline in the monsoon strength after 8 ± 1 ka resulted in reduced fluvial discharge and lower sediment transport capacity of the Alaknanda River, leading to valley fill incision and the development of terraces. The study suggests that fluvial dynamics in the Alaknanda valley were modulated by monsoon variability and the role of tectonics was subordinate, limited to providing accommodation space and post-deposition modification of the fluvial landforms. Copyright © 2010 John Wiley & Sons, Ltd.