Open Access

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

Atul K. Singh
Atul K. Singh
, 
Manoj K. Jaiswal
Manoj K. Jaiswal
, 
Jitendra K. Pattanaik
Jitendra K. Pattanaik
 and 
Maha Dev
Maha Dev
   | Nov 12, 2016
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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
© 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.

(a) The study region lies in the northern part of West Bengal, India. (b) The figure shows the tectonic division of the Himalayas and the present study area, (c) The figure shows the major geomorphic features in the study area. The sampling sites are marked with red star. The northern most fault known as Gorubathan is marked by black line just below the Samsing surface. The two other E-W scarps/faults viz. Matiali and Chalsa are also shown in the figure. The NNE-SSW and nearly N-S scarps along which the Murti and Neora rivers flow respectively are also shown in the figure (after Goswami et al., 2013). (d) This is the Google earth image of the region showing the major rivers in the area. A red star shows the OSL sample location of S-5 coinciding with the location of radiocarbon date provided by Guha et al. (2007) (e) The figure shows the height of the different geomorphic features from the river bed near the Chalsa scarp along the line AB in Fig. 1c (after Goswami et al., 2013).
(a) The study region lies in the northern part of West Bengal, India. (b) The figure shows the tectonic division of the Himalayas and the present study area, (c) The figure shows the major geomorphic features in the study area. The sampling sites are marked with red star. The northern most fault known as Gorubathan is marked by black line just below the Samsing surface. The two other E-W scarps/faults viz. Matiali and Chalsa are also shown in the figure. The NNE-SSW and nearly N-S scarps along which the Murti and Neora rivers flow respectively are also shown in the figure (after Goswami et al., 2013). (d) This is the Google earth image of the region showing the major rivers in the area. A red star shows the OSL sample location of S-5 coinciding with the location of radiocarbon date provided by Guha et al. (2007) (e) The figure shows the height of the different geomorphic features from the river bed near the Chalsa scarp along the line AB in Fig. 1c (after Goswami et al., 2013).

The figure shows different sampling location along with the field photographs from different locations. (a) The figure shows the JRM section from which the sample JRM-1 was collected (from T4) on the banks of Juranti river near Matiali scarp. The 42° south dipping beds are marked by dashed black lines (Scale = 15 cm). (b) This figure shows a part of KRC section from which samples KRC-1 and KRC-2 (both from T2) were collected. KRC-3 was collected from T4 and was behind this section, KRC-4 was collected from T1 to the south of this photograph. The dashed black line shows the deformed beds and the orange line shows the unconformity in the T2 terrace. The height of section is about 20 m from river bed. (c) The photograph of the JRC section from which the samples JRC-1 and JRC-2 were collected, in the foreground Juranti river could be seen. Sampling location of JRC-1 is marked and the sample JRC-2 was collected from the west facing scarp of the same section (along Neora river). A scale of ~2m is marked in the lower right corner of the image. (d) NRM-1 was collected from this section, it represents the T3 terrace and parallel horizontal beds of sediments could be seen. NRM-2 was collected from the opposite bank. The black and white scale in the figure is 50 cm. (e) The photograph shows the NRC section, from which the samples NRC-1 and NRC-2 were collected (both from T4). The whole section has a very gentle slope towards north. For scale two students could be seen (~170 cm) in the right side of the photograph. The sample NRC-3 was collected from the opposite bank of the Neora river.
The figure shows different sampling location along with the field photographs from different locations. (a) The figure shows the JRM section from which the sample JRM-1 was collected (from T4) on the banks of Juranti river near Matiali scarp. The 42° south dipping beds are marked by dashed black lines (Scale = 15 cm). (b) This figure shows a part of KRC section from which samples KRC-1 and KRC-2 (both from T2) were collected. KRC-3 was collected from T4 and was behind this section, KRC-4 was collected from T1 to the south of this photograph. The dashed black line shows the deformed beds and the orange line shows the unconformity in the T2 terrace. The height of section is about 20 m from river bed. (c) The photograph of the JRC section from which the samples JRC-1 and JRC-2 were collected, in the foreground Juranti river could be seen. Sampling location of JRC-1 is marked and the sample JRC-2 was collected from the west facing scarp of the same section (along Neora river). A scale of ~2m is marked in the lower right corner of the image. (d) NRM-1 was collected from this section, it represents the T3 terrace and parallel horizontal beds of sediments could be seen. NRM-2 was collected from the opposite bank. The black and white scale in the figure is 50 cm. (e) The photograph shows the NRC section, from which the samples NRC-1 and NRC-2 were collected (both from T4). The whole section has a very gentle slope towards north. For scale two students could be seen (~170 cm) in the right side of the photograph. The sample NRC-3 was collected from the opposite bank of the Neora river.

Log showing stratigraphic position of different sections from which the samples were collected.
Log showing stratigraphic position of different sections from which the samples were collected.

(a) The BLSL shine down curve for the quartz from the JRM-1 sample. (b) The laboratory generated dose growth for the sample JRM-1. (c) The dose recovery test was performed on the S-5, laboratory dose of 151.4 Gy was administered and it was recovered, the red dots represent the recovered doses. It was found that all the five aliquots showed very good recovery with less than 10% of deviation from the given lab dose. (d) Histogram showing the dose distribution for the sample JRM-1.
(a) The BLSL shine down curve for the quartz from the JRM-1 sample. (b) The laboratory generated dose growth for the sample JRM-1. (c) The dose recovery test was performed on the S-5, laboratory dose of 151.4 Gy was administered and it was recovered, the red dots represent the recovered doses. It was found that all the five aliquots showed very good recovery with less than 10% of deviation from the given lab dose. (d) Histogram showing the dose distribution for the sample JRM-1.

OSL age table of analyzed samples showing various parameters for age calculation.

S.No.Sample NameTerraceU (ppm)Th (ppm)K (%)Moisture (%)ED (Gy)Dose Rate (Gy/ka)Age (ka)No. of discs
1JRM-1T42.30±0.0119.61±0.082.28±0.0215±5590.6±55.33.5±0.2171±1815
2NRM-1T32.81±0.0213.53±0.672.59±0.0210±5217.3±57.23.6±0.259.7±1610
3NRM-2T42.41±0.0616.89±0.572.43±0.0210±5306.7±26.73.6±0.284.6±8.67
4S-53.14±0.0318.40±0.651.27±0.0115±575.6±18.92.7±0.127.8±726
5KRC-1T24.71±0.1212.02±0.311.74±0.0110±5158±36.83.2±0.247.7±10.713
6KRC-2T23.32±0.0323.71±0.562.36±0.0310±5172.7±414.2±0.241.4±1018
7KRC-3T42.09±0.1012.58±0.061.47±0.0110±5199.4±4.62.5±0.180.8±4.718
8KRC-4T12.31±0.0113.07±0.101.75±0.0110±578.1±23.22.8±0.228.6±8.515
9NRC-1T42.26±0.0610.64±0.131.51±0.0815±5209±44.52.3±0.189.1±17.311
10NRC-2T42.94±0.1215.81±0.161.79±0.0210±5226.3±60.93.1±0.272.6±19.918
11NRC-3T23.17±0.0215.98±0.032.41±0.0110±5211.6±68.13.7±0.259.4±18.113
12JRC-1T42.88±0.0215.97±0.092.28±0.2910±5369.4±91.93.6±0.399.03±25.311
13JRC-2T1a2.90±0.0414.75±0.281.81±0.1210±517.9±3.83±0.25.9±1.312

Details of sampling location along with coordinates and relative stratigraphic positions.

S. No.Sample NameHeight above mean sea level of River bed (m)LocationThickness of sand bed (m)Height from river bed (m)
1JRM-126°56'34.1"N88°47'16.6"E287Western bank of Juranti river, near Matiali scarp, basement of T40.51.5
2NRM-126°56'14.6"N88°45'41.3"E251Eastern bank of Neroa, near Matiali scarp, from T30.53
3NRM-2-do--do-Western bank of Neroa near Matiali scarp from the T40.31
4S-526°57'51.2"N88°55'51.8"E358Uplifted scarp material near Taljhora0.54
5KRC-126°53'1.1"N88°47'32.9"E178Western bank of Kurti river near Chalsa scarp, from T20.53
6KRC-2-do--do--do-1.0518
7KRC-3-do--do-Western bank of Kurti river near Chalsa scarp, from T40.2615
8KRC-4-do--do-Western bank of Kurti river near Chalsa scarp, from T10.283.5
9NRC-126°53'37.3"N88°46'30.9"E188Eastern bank of Neora river near Chalsa scarp from T40.612
10NRC-2-do--do-Eastern bank of Neora river near Chalsa scarp from T40.330
11NRC-326°53'13.6"N88°46'22.2"E166Western bank of Neora river near Chalsa scarp from T20.33
12JRC-126°54'05.1''N88°46'13.4"E189Near confluence of Neora and Juranti rivers from T40.51.5
13JRC-2-do--do-Near confluence of Neora and Juranti from T1a0.32
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