<abstract xmlns="http://www.w3.org/1999/xhtml">Alluvial fans are important geomorphic archives because of its strategic location at mountain front which can provide clues to the past climate and tectonics. In general, they provide information about optimum climate condition suitable for fan formation. We provide a detailed luminescence chronology of alluvial fan in north West Bengal, India. The regional fan surface (T44) has been dissected by E-W trending Himalayan thrusts known as Matiali and Chalsa thrusts and have various terraces named as T3, T2 and youngest one as T1. Luminescence ages suggest that the formation of the alluvial fan (regional surface) started before 171 ka and continued till 72 ka covering a time span of nearly 100 ky; suggesting of weaker monsoon at 72 ka. Matiali fault activated after 171 ky. Chalsa fault is suggested to be active during 48–41 ka. The last aggradational phase was around 6 ka which led to the formation of T1a terrace. The study suggests that climatic fluctuation during the period were shaping the morphology of the alluvial fan, along with tectonic activities on the two faults.</abstract>

Alluvial fans are important geomorphic archives because of its strategic location at mountain front which can provide clues to the past climate and tectonics. In general, they provide information about optimum climate condition suitable for fan formation. We provide a detailed luminescence chronology of alluvial fan in north West Bengal, India. The regional fan surface (T44) has been dissected by E-W trending Himalayan thrusts known as Matiali and Chalsa thrusts and have various terraces named as T3, T2 and youngest one as T1. Luminescence ages suggest that the formation of the alluvial fan (regional surface) started before 171 ka and continued till 72 ka covering a time span of nearly 100 ky; suggesting of weaker monsoon at 72 ka. Matiali fault activated after 171 ky. Chalsa fault is suggested to be active during 48–41 ka. The last aggradational phase was around 6 ka which led to the formation of T1a terrace. The study suggests that climatic fluctuation during the period were shaping the morphology of the alluvial fan, along with tectonic activities on the two faults.

Luminescence chronology of alluvial fan in North Bengal, India: Implications to tectonics and climate

Department of Earth Sciences, Indian Institute of Science Education and Research, Kolkata 741246,

Environment and Earth Sciences, Central University of Punjab, Bathinda-151001, Punjab,

Geochronometria

This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Alluvial fans are important geomorphic archives because of its strategic location at mountain front which can provide clues to the past climate and tectonics....

Luminescence chronology of alluvial fan in North Bengal, India: Implications to tectonics and climate

Article Category: Research Article

Published Online: Nov 12, 2016

Page range: 102 - 112

Received: Jun 30, 2015

Accepted: Jul 01, 2016

DOI: https://doi.org/10.1515/geochr-2015-0037

Keywords
OSL dating, SAR, North Bengal Himalayas, alluvial fan, fluvial terraces

© 2015 A. K. Singh

This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Luminescence chronology of alluvial fan in North Bengal, India: Implications to tectonics and climate

Article Category: Research Article

Published Online: Nov 12, 2016

Page range: 102 - 112

Received: Jun 30, 2015

Accepted: Jul 01, 2016

DOI: https://doi.org/10.1515/geochr-2015-0037

KeywordsOSL dating, SAR, North Bengal Himalayas, alluvial fan, fluvial terraces

© 2015 A. K. Singh

This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Keywords
OSL dating, SAR, North Bengal Himalayas, alluvial fan, fluvial terraces