ArticlePDF Available

Abstract and Figures

Sands along Brahmaputra River of Bangladesh have long been considered to be a source of heavy minerals (HMs) since it traversed a long way through various terrains. An attempt has been made under this research work to determine the kinds and amounts of heavy minerals in the sands sourced from the river system. Samples from 14 locations along Brahmaputra River covering 30 km distance from upstream to downstream of the river are found to contain different heavy minerals concentration with a range of 7.92-25.16 weight% with the remaining of the sample comprising silicate and aluminosilicates. Mineral characterization from peak positions in diffractogram of X-ray Diffraction (XRD) evaluate quartz, feldspar and mica are major categories light mineral while rutile, magnetite, illmenite, zircon, monazite, garnet, uranium arsenide and uranium fluoride are the major types heavy minerals. Ilmenite and rutile are main contributors of total heavy mineral (THM). Titanium bearing minerals ilmenite and rutile contributes 26.22%-31.01% and 14.57%-23.50% of THM. In the present study area, most of the sands are found to be fine and medium grained as obtained from the particle sizes analysis using 18-to 230-mesh.
Content may be subject to copyright.
International Journal of Geosciences, 2016, 7, 47-52
Published Online January 2016 in SciRes. http://www.scirp.org/journal/ijg
http://dx.doi.org/10.4236/ijg.2016.71005
How to cite this paper: Khalil, Md.I., Khan, Md.N.I., Kabir, Md.Z., Majumder, R.K., Ali, Md.I., Paul, D. and Islam, S.M.A.
(2016) Heavy Minerals in Sands along Brahmaputra (Jamuna) River of Bangladesh. International Journal of Geosciences, 7,
47-52. http://dx.doi.org/10.4236/ijg.2016.71005
Heavy Minerals in Sands along
Brahmaputra (Jamuna) River
of Bangladesh
Md. Ibrahim Khalil1*, Md. Nazrul Islam Khan2, Md. Zafrul Kabir1, Ratan Kumar Majumder1,
Md. Idris Ali3, Debasish Paul3, Syed Mohammad Azharul Islam4
1Nuclear Minerals Unit, Atomic Energy Research Establishment, Dhaka, Bangladesh
2Material Science Division, Atomic Energy Center, Bangladesh Atomic Energy Commission, Dhaka, Bangladesh
3Health Physics and Radioactive Waste Management Unit, Atomic Energy Research Establishment, Dhaka,
Bangladesh
4Department of Physics, Jahangirnagar University, Dhaka, Bangladesh
Received 25 December 2015; accepted 25 January 2016; published 28 January 2016
Copyright © 2016 by authors and Scientific Research Publishing Inc.
This work is licensed under the Creative Commons Attribution International License (CC BY).
http://creativecommons.org/licenses/by/4.0/
Abstract
Sands along Brahmaputra River of Bangladesh have long been considered to be a source of
heavy minerals (HMs) since it traversed a long way through various terrains. An attempt has
been made under this research work to determine the kinds and amounts of heavy minerals in
the sands sourced from the river system. Samples from 14 locations along Brahmaputra River
covering 30 km distance from upstream to downstream of the river are found to contain dif-
ferent heavy minerals concentration with a range of 7.92 - 25.16 weight% with the remaining
of the sample comprising silicate and aluminosilicates. Mineral characterization from peak po-
sitions in diffractogram of X-ray Diffraction (XRD) evaluate quartz, feldspar and mica are major
categories light mineral while rutile, magnetite, illmenite, zircon, monazite, garnet, uranium
arsenide and uranium fluoride are the major types heavy minerals. Ilmenite and rutile are
main contributors of total heavy mineral (THM). Titanium bearing minerals ilmenite and rutile
contributes 26.22% - 31.01% and 14.57% - 23.50% of THM. In the present study area, most of
the sands are found to be fine and medium grained as obtained from the particle sizes analysis
using 18- to 230-mesh.
Keywords
Heavy Minerals, River, Sand, Bangladesh
*Corresponding author.
Md. I. Khalil et al.
48
1. Introduction
Minerals are the composite of different elements and occur naturally as crystalline inorganic substances in sedi-
ments. Mineral sediments, sands and mud are weathered from mountain belts, transported by rivers, glaciers or
wind and deposited. Minerals are classified into two types on the basis of its density such as light minerals (spe-
cific density less than 2.9/103 kg·m3) and heavy minerals (specific density greater than 2.9/103 kg·m3) [1]. The
erosion of weathered rocks and minerals results in the concentration of the more resistant and higher specific
gravity (density) minerals (2.9/103 kg·m3).
The Brahmaputra River originating in Tibet and flowing through Tibet and the north-eastern part of India en-
ters Bangladesh in Kurigram District. The immense amount of sediment carried by the Brahmaputra River, de-
rived from intense erosion of the Himalayas (in the north), is delivered to the Bay of Bengal. During transporta-
tion sandy materials laid down on the bed of the river, forming sand bars. The thickness of sand deposits up to
gravel bed is 44 m [2]. For economic exploitation of mineral sands, it is necessary to identify the minerals
present, quantify total reserves of sand deposits, determine the contents and quality of economic minerals, and
find the market demands in the country and abroad. Non-marine alluvial sand placer deposits are also known to
be sources of heavy minerals (HMs), e.g. Gbangbama deposit in Sierra Leone [4], central Kalimantan, Borneo,
Indonesia [3]. Compared to HM sand accumulations in beach sand deposits, the concentration of HMs in river
sands is generally lower, with as little as 5% - 10% total HMs [4]. Heavy mineral river deposits may be promi-
nent in Bangladesh as the river and drainage systems within Bangladesh are extensive, carrying large quantities
of sandy sediments to the coastal regions, e.g. the Brahmaputra River carries an estimated (7.35 - 8.00) × 108
tone of sediment per year [5] [6]. The alluvial sediments contain both light and HMs with the HMs generally
deposited on the bed of the river systems forming HM-rich sand bars.
Heavy minerals, having higher specific gravity, occur in all sands. Some sands contain large enough concen-
trations of valuable heavy minerals to serve as commercial sources of these minerals. The kinds and amounts of
heavy minerals occurring in Brahmaputra River are of great interest to warrant commercial exploitation. An at-
tempt has been made through this study to know the heavy minerals concentration together with individual
heavy mineral quantification along Brahmaputra River in Bangladesh.
2. Materials and Methods
2.1. Study Area
The present study area covers Kurigram sadar, Ulipur and Chilmari Upazila of Kurigram district which is tra-
versed by Brahmaputra (Jamuna) river (25˚48'26"; 89˚45'09" - 25˚33'32"; 89˚41'01"). The study area covers sta-
ble sand bars in an area of 30 km × 4 km from upstream to downstreamof the Brahmaputra River in the Kuri-
gram district, north-eastern Bangladesh (Figure 1).
2.2. Sample Collection and Analysis
The present study covers about 30 km × 4 km area from which 14 successive locations were selected and num-
bered as DK1-DK14. From each location two samples were collected from sand bar (chars”) and river bed found
in the study area. The sample locations were recorded in terms of degree-minute-second (latitudinal and longitu-
dinal position) using a hand-held global positioning system (GPS) (Model: Magellan-Map-410) unit. Each loca-
tion is separated by a distance of approximately 2 km (approximately 1 minute in co-ordinate system). The sam-
ples were collected at the depth of 0 - 5 cm by plastic spade during summer period of 2014 and collected sam-
ples were packed in polyethylene bags. Each sample has the weight of about 2 kg. The collected samples were
air dried at room temperature in open air.
Preparation and preliminary analysis of sediment samples were carried out as per the procedure given in
Carver [7] and Solai et al. [8]. Heavy mineral separation was carried out using heavy liquid bromoform of 2.89
specific gravity as per the standard procedures outlined by Milner [9]. The total heavy mineral percentages
(THM) were calculated. Using a hand magnet, magnetic minerals (magnetite) were separated from the heavy
mineral fractions and the weight percentage was estimated. The samples were also examined to measure their
granulometric fractions such as contents of sand, silt and clay. Using an ASTM sieve, about 100 g of sediment
was taken for separation of sand, silt and clay fractions by sieving.
Md. I. Khalil et al.
49
Figure 1. Location map of the study area.
For mechanical separation 10 kg raw sand samples were dried in the sun to remove moisture. Separation of
heavy and light minerals was carried out depending on specific gravity/density of the minerals using labora-
tory shaking table. For each sample, heavy minerals fraction obtained after density separation dried in burner.
Magnetite, ilmenite, rutile and zircon mixed with others were separated using Induced Roll Magnetic Separa-
tor (IRMS) applying fixed magnetic intensity at 0.5 amp, 2.5 amp, 5.5 amp, and 7.5 amp condition, respec-
tively.
Powder X-ray Diffraction (XRD) is a versatile technique that can be used to identify any crystalline sub-
stances, such as most minerals. It can also be used to quantify the proportions of different minerals or indeed
many other substances when they are present in a mixture. Powder X-ray diffraction analysis is seemingly the
perfect technique for crystalline-mixture analysis, since each component of the mixture produces its characteris-
tic pattern independently of the others, making it possible to identify the various components by unscrambling
their superposed patterns. An X-ray beam of known wavelength is focused on a powdered sample and X-ray
diffraction peaks are measured using a detector. In the present study X-ray diffraction technique has been uti-
lized to discern these properties. The phase identification was performed using Philips X’Pert Pro multipurpose
X-ray diffractometer which uses copper Kα radiation. X-ray generator operated at 40 kV and 30 mA, and all
scans were run at a speed of 2˚ per minute, from 10˚ to 70˚, with a continuous step size of 0.02.
3. Results and Discussion
3.1. Heavy Mineral Separation Analysis
The heavy mineral separation analysis has been carried out to know the total heavy mineral (THM) weight per-
centage in the present samples. Weight percentage of separated heavy minerals in most of the samples varied
from 8% to 15%, while in one sample it reaches to 25%; similar THM value is reported for Brahmaputra river
sand [10]. The THM percentage is varied greatly from site to site. It is minimum in DK13 and it is maximum in
DK4 (Figure 2). Other sites are having intermediate values.
Average THM value in the sand samples of the study area is 12.40% while low (within10%) THM percentage
is encountered in four locations. These values of THM are higher than the other river of Bangladesh as observed
in someshari river [11]. The actual sorting and concentration of heavy minerals takes place due to the actions of
two principal agents i.e. action of waves/currents and wind. Mechanical separation of raw sand using Induced
Md. I. Khalil et al.
50
Roll Magnetic Separator (IRMS) resulted to separate magnetite, ilmenite, rutile and zircon mixed with other
minerals. Separation of samples DK1, DK8 and DK12 reveals that ilmenite and rutile are main contributors of to-
tal heavy mineral (THM). Titanium bearing minerals ilmenite and rutile contributes 26.22% - 31.01% and 14.57%
- 23.50% of THM.
3.2. Granulometric Analysis
Granulometric analysis has been carried out to know the content of sand, silt and clay (%) in the present sedi-
ments. Percentage of sand, silt and clay (%) content of the samples are presented in Figure 3. Sand is the main
constituent in all the sampling locations, which varied from 91.87% to 99.74%. Silt content is the least constitu-
ent which varied from 0.03% to 7.98%. In the samples studied, the heavy minerals occur predominantly in the
60- to 200-mesh sieve grade (Table 1). 75% - 90% heavy minerals of THM occur in 60- to 120-mesh while
some heavy mineral grains are finer but most of the samples contain negligible amounts of material of this grain
size. In a given sample, the heavy minerals are primarily finer grained than the average grain size of the whole
sample.
Figure 2. Heavy minerals weight% in the sand sample of the study area.
Figure 3. Distribution of sand, silt and clay (%) content in sediment samples of the study area.
0.00
5.00
10.00
15.00
20.00
25.00
30.00
Heavy Minerals%
8.37
14.38
12.92
25.16
10.92
12.43
10.33
9.87
10.95
13.01
14.83
11.52
7.92
10.00
DK1
DK2
DK3
DK4
DK5
DK6
DK7
DK8
DK9
DK10
DK11
DK12
DK13
DK14
Md. I. Khalil et al.
51
3.3. X-Ray Diffraction
X-ray diffraction is a unique analytical tool for the analysis of geological samples. It is the most important and
informative technique for identification and characterization of minerals in the sediments. The XRD spectra
were recorded for all the sediment samples to determine the mineralogical composition. A representative dif-
fractogram is shown in Figure 4 along with name of the minerals present.
The XRD pattern (Figure 4) indicates that the compositions are of single-phase structure since no ambiguous
reflections other structure is evidenced. Analyzing the XRD patterns we notice that the position of the peaks
comply with the reported value. All diffraction peaks of the studied samples are compared to the reported struc-
ture for relevant base sand samples. The observed peaks at 2 theta value of 18.37, 21.24, 23.86, 26.97, 29.01,
30.10, 35.42, 36.95, 38.43, 39.62, 40.64, 44.24, 46.10, 47.81, 50.53, 53.43, 55.30, 60.28, 63.68, 68.55 confirmed
that the sand is mainly containing Quartz, Monazite, Feldspar, Uranium Fluoride, Rutile, Zircon, Hematite,
Kayanite, Uranium Arsenide. Observed peak positions were matched against the International Centre for Dif-
fraction Data (ICDD) Joint Committee on Powder Diffraction System (JCPDS) card database.
The Brahmaputra drains the Tibetan Plateau of China and is dominated by upland tributaries originating in the
Himalayas. The Brahmaputra flows through various rock types including Precambrian metamorphics (high-grade
schists, gneisses, quartzites, metamorphosed limestones), felsic intrusives, and Paleozoic-Mesozoic sandstones,
shales and limestones [12]. From the heavy mineral assemblage study of the Brahmaputra-Jamuna River sand, it
can be postulated that there are several types of source rock complexes are exist in the specific source area
Table 1. Grain size distribution and weight% of heavy minerals.
Heavy Mineral Wt%
60-mesh 120-mesh 200-mesh Pan
Ilmenite 8.79 - 25.72 54.76 - 63.27 13.50 - 19.45 5.33 - 8.02
Rutile 11.33 - 55.82 36.03 - 62.42 7.12 - 22.00 1.00 - 4.26
Zircon + others 15.25 - 53.03 42.21 - 73.41 4.51 - 11.00 0.10 - 0.40
10 20 30 40 50 60 70
0
200
400
600
800
1000
R
M
R, Z, M
K
UF
F, UAs
Q, R
Q, F, M
FeO
Q, UAs
R
R, KQ, FeO
Q, UAs, UF
F, Z, K
F, M, FeO
R, M, Z F, Z
Q, F, M
UF
Intensity
2Theta(deg)
DK-11
Figure 4. The representative XRD pattern of the sand sample. M = Monazite, Q = Quartz, F = Feldspar, UF = Uranium Flu-
ride, R = Rutile, Z = Zircon, FeO = Magnetite, K = Kyanite, UAs = Uranium Arsenide.
Md. I. Khalil et al.
52
mainly Lesser Himalayan and Indo-Burman Ranges with having little influence of Himalayan tributaries and
north Himalayan [13]. Heavy minerals obtained in the study might have the similar source as described by the
researchers.
4. Conclusion
The heavy fractions of sands along the Brahmaputra River are primarily the source of the iron titanium and iron
oxide minerals magnetite and ilmenite. Most of the heavy minerals are in the 60- to 200-mesh size range. Most
of the samples have between 8 and 15 percent heavy minerals. Ilmenite ranges from about 4 to 9 percent and ru-
tile ranges from about 3 to 5 percent. Such percentages are much higher than those of Someshari river sands of
Bangladesh. Considering the high heavy mineral concentration in river sands, the possibility of commercial uti-
lization of the heavy minerals in sands along the Brahmaputra River is quite a burning issue at the present time.
Acknowledgements
The authors are thankful to local Administration and people of the study area for their assistance during field
work. The authors are also grateful to laboratory staffs of Nuclear Minerals Unit of Atomic Energy Research
Establishment for their assistance in laboratory analysis. This work is financed by the Ministry of Science and
Technology, Government of The People’s Republic of Bangladesh under the Special Allocation program 2014-
2015.
References
[1] de Meijer, R.J., James, J.R., Jennings, P.J. and Koeyers, J.E. (2001) Cluster Analysis of Radionuclide Concentration in
Beach Sand. Applied Radiation and Isotopes, 54, 535-542. http://dx.doi.org/10.1016/S0969-8043(00)00196-2
[2] Umitsu, M. (2001) Holocene Sea-Level Changes and Coastal Evolution in Japan. The Quaternary Research, 30, 187-
196.
[3] Aral, H., Pownceby, M.I. and Im, J. (2008) Characterisation and Beneficiation of Zircon-Rich Heavy Mineral Concen-
trates from Central Kalimantan (Borneo, Indonesia). Transactions of the Institution of Mining and Metallurgy Section
B—Applied Earth Science, 117, 77-87. http://dx.doi.org/10.1179/174327508X339837
[4] Force, E.R. (1991) Geology of Titanium-Mineral Deposits. Geological Society of America, Special Paper 259.
http://dx.doi.org/10.1130/spe259-p1
[5] Coleman, J.M. (1969) Brahmaputra River: Channel Processes and Sedimentation. Sedimentary Geology, 3, 139-239.
http://dx.doi.org/10.1016/0037-0738(69)90010-4
[6] Rahman, M.A., Biswas, P.K., Zaman, M.N., Miah, M.Y., Hossain, T. and Imamul Huq, S.M. (2012) Characterisation
of the Sand of Brahmaputra River of Bangladesh. Bangladesh Journal of Scientific and Industrial Research, 47, 167-
172.
[7] Carver, R.E. (1971) Heavy Mineral Separation. In: Carver, R.E., Ed., Procedures in Sedimentary Petrology, Wiley,
NewYork, 427-452.
[8] Solai, A., Suresh Gandhi, M., Chandrasekaran, K. and Ram Mohan, V. (2009) Distribution of Heavy Mineral Sand
Their Provenance Studies in and around Tamiraparani Estuary and off Tuticorin Tamil Nadu, India. International
Journal of Earth Sciences and Engineering, 2, 527-543.
[9] Milner, I. (1962) Sedimentary Petrology. George Allen and Unwin Ltd., London, 643-715.
[10] Rahman, M.A., Pownceby, M.I., Haque, N., Bruckard, W.J. and Zaman, M.N. (2014) Characterisation of Titanium-
Rich Heavy Mineral Concentrates from the Brahmaputra River Basin, Bangladesh. Applied Earth Science (Transac-
tions of the Institution of Mining and Metallurgy B), 123, 222-233.
[11] Rahman, M.A., Zaman, M.N., Biswas, P.K., Sultana, S. and Nandy, P.K. (2015) Physical Separation for Upgradation
of Valuable Minerals: A Study on Sands of the Someswari River. Bangladesh Journal of Scientific and Industrial Re-
search, 50, 53-58. http://dx.doi.org/10.3329/bjsir.v50i1.23810
[12] Huizing, H.G.J. (1971) A Reconnaissance Study of the Mineralogy of Sand Fractions from East Pakistan Sediments
and Soils. Geoderma, 6, 109-133. http://dx.doi.org/10.1016/0016-7061(71)90029-2
[13] Jasy, J.B., Rahman, M.J.J. and Yeasmin, R. (2010) Sand Petrology of the Exposed Bar Deposits of the Brahmapu-
tra-Jamuna River, Bangladesh: Implication for Provenance. Bangladesh Geoscience Journal, 16, 1-22.
... On average, the beach The occurrence of large amounts of HMs in the bedload of Brahmaputra-Jamuna River sediments has been known for decades [10][11][12][13][14][15]. Recent studies to examine the potential for recovering VHM from sand bars of the northern Brahmaputra-Jamuna River have been reported by Rahman et al. [16][17][18] and Khalil et al. [19]. Rahman et al. [18] determined that the THM percentage of the Brahmaputra-Jamuna sand bars was lower than the beach sand deposits, ranging from 4-17 wt%. ...
... While exploitation of VHMs from river sand deposits is uncommon, primarily due to the typically low grades encountered, the river systems in Bangladesh are constantly renewed through annual transport of ~1800 The occurrence of large amounts of HMs in the bedload of Brahmaputra-Jamuna River sediments has been known for decades [10][11][12][13][14][15]. Recent studies to examine the potential for recovering VHM from sand bars of the northern Brahmaputra-Jamuna River have been reported by Rahman et al. [16][17][18] and Khalil et al. [19]. Rahman et al. [18] determined that the THM percentage of the Brahmaputra-Jamuna sand bars was lower than the beach sand deposits, ranging from 4-17 wt%. ...
Article
Full-text available
Abstract:Bangladesh’s heavy minerals deposits in river systems remain largely unexplored withpast research restricted to beach placer deposits along the south-eastern coastline of the country.In this study, 64 samples were collected from stable sand bars from the northern BrahmaputraRiver. The average total heavy minerals (THM) from all sample sites was 10.73 wt%, with theTHM concentrations generally highest at the outermost edges of the river and lowest within themid-channel regions. There was no variation in THM content from north (upstream) to south(downstream). Valuable heavy minerals (VHMs) magnetite, ilmenite, garnet and zircon made uparound 25–30 wt% of the THM content, with other heavy minerals including amphibole, pyroxene,kyanite, sillimanite, monazite, apatite and xenotime making up the remaining 70–75 wt%. A VHMdistribution map showed that the upstream division of the studied area appeared to be the mostprospective for valuable heavy minerals. A bench scale heavy mineral sands beneficiation flowsheetinvolving unit processes employing gravity, magnetic and electrostatic properties was designed andbased on a detailed characterisation and phase analysis of the resulting fractions, it was determinedthat VHMs made up ~2 wt% of the material recovered. Of these, garnet and ilmenite made up the bulkof the VHMs at levels of 0.88 and 0.51 wt%, respectively, with recoveries of >83%. Characterisation ofthe concentrates showed that further refinement of the processing conditions is required to generateconcentrates that are potentially suitable for commercial applications. Keywords:heavy minerals; distribution; separation; characterisation; Brahmaputra River sand
... Scrutinizing on these heavy minerals and their characteristics help us in unraveling the extrabasinal and intrabasinal pathways i.e. source area weathering and hydraulic processes respectively, which influences the formation of HM deposits (Kumar and Sreejith, 2010). Previously, the majority of studies targeting upon placers of the Brahmaputra is centered on their economic potential and the way of transport and deposition of their heavy minerals (Goodbred and Kuehl, 1999;Galy and France-Lanord, 1999;Gleason et al., 2002;Best et al., 2007;Garzanti et al., 2004Garzanti et al., , 2010Pickering et al., 2014;Khalil et al., 2016;Rahman et al., 2014Rahman et al., , 2019. Besides, the provenance of the river detritus were discussed through bulk sediment geochemistry (Bhuiyan et al., 2011;Rahman et al., 2020), but rarely expanded to an in-depth mineralogical study so as to fine-tune the pathway and ultimate source of these ore minerals with respect to the Himalayan upliftment and exhumation. ...
Article
The present study describes results obtained from the chemistry of detrital heavy minerals i.e. pyroxene, amphibole, biotite, garnet, epidote and Fe-Ti oxides in fluvial sediments of the northern Brahmaputra River (Bangladesh) with an aim to determine conditions of their petrogenesis and provenance. The primary and secondary genera of ferromagnesian minerals occurred in calc-alkaline and peraluminous subduction zone. In which, the garnets are Fe-rich, indicating mostly almandine component (Alm65–Pyp16–Grs8–Sps6 averagely), occurred in medium to high grade metasedimentary rocks in the Lesser Himalaya (LH), along the Main Central Thrust (MCT) and the eastern Himalayan syntaxis. Besides, the fingerprint of omphacite and actinolite owe to ascertain the co-existence of garnet developed in ultrahigh-pressure (UHP) eclogites that may also be drained from the Tso Morari massif. Augite to aegirine-augite pyroxenes emphasizes Fe enrichment in basaltic systems and high to ultrahigh grade metamorphic rocks, which are exposed in the LH, Shillong Plateau, Mikir Hills, South Tibetan Detachment System (STDS), eastern Himalayan syntaxis and Tso Morari massif. Geochemistry and thermobarometry of the primary magmatic amphiboles and biotites manifest the source of granitoid and granodiorite like bodies, and their windows are exposed in the Bomi–Chayu, Gangdese arcs and the western Arunachal Himalaya. Again, metamorphosed Fe-Ti oxide minerals are well-exposed along the NE Lesser Himalaya, where magmatic derivative of Fe-Ti oxide minerals were modified through the diffusional processes in low-grade metamorphism (534–562 °C with 10–22.1–10−21.5 fo2). Integrating the aforementioned discussion with the thermochronology, it is evident that the eastern Himalayan syntaxis is the major source of sediment flux, which is carried mostly by the upper Himalayan tributaries i.e. Yigong, Parlung, Dibang and Lohit. Also, the lower Himalayan tributaries i.e. Subansiri and Manas drain the sequestered derivatives dominantly from the Arunachal Himalayan. Tso Morari eclogites (NW Himalaya) have also contribution somewhat of dense minerals to the Tsangpo-Brahmaputra River system. Thus, scrutinizing the fingerprint of single-grain detrital minerals provides key information regarding the source terrains and tectonics of the Himalayan sequences.
... From the XRD analysis in our sediment samples, we found Feldspar (F), Zircon (Z), Monazite (M) and Quartz (Q) as the key minerals, which were identified by comparing with Joint Committee on Powder Diffraction System (JCPDS) database. The findings of the study were also matched with the study performed on the sandbars of Jamuna River in Bangladesh by Khalil et al. (2016). The peak of the samples observed at 2 theta values of 6. 26, 8.8, 12.48, 20.82, 22.06, 26.6, 27.98, 29.8, 36.52, ...
Article
Increased urbanization and industrial development has led to diminished mainland for agricultural activities. This gives rise to the global temperature and reduction in the agricultural productivity. In the context of agri-cultural intensification, riverine ecosystem plays an important role. The sandbars provide adequate and stable socio-economic returns by sustaining agronomic and farming activities. However, a comprehensive under-standing of cropping pattern and farming activities involving the societal, environmental and socio-economic aspects is necessary. This study focuses on investigating the knowledge on sandbar utilization and developing an optimization model to understand the current activities practiced in riverine ecosystems. Sandbar suitability for agricultural purposes was evaluated by performing sediment analysis, which plays an important role in the growth of crops in the sandbars. The experimental observations and field studies revealed that the vegetated and cultivated sandbars consist of silty and loamy soils, favoring agriculture and the newly formed sandbars were devoid of silt and clay. Subsequently, the optimization model aimed at supporting the decisions for planning of agricultural activities in sandbars. The optimal results when compared with the existing practice in a selected sandbar, showed reduction in the area allocated to rice and oilseeds, alongside an increase in percentage of fi-bres, cereals, potato and vegetables. The percentage area under rice cultivation reduced by 8% and fibres, vegetables and cereals increased by 7% annually. The net annual benefit under optimal allocations increased from 1.32 Billion Rupees to 1.53 Billion Rupees against the existing pattern. These results were significant in perceiving the shift in the pattern of agricultural activities from the prevailing traditional practices to newer dimensions, which would be beneficial for the farmers to increase their revenue. The suggestions from the study provides a comprehensive understanding and interactions between the agricultural system and society via optimization approaches, that will benefit the impoverished and can be a boon into the agriculture revolution amidst urban expansions.
... These light and heavy minerals might be originated from the source rocks as the river travels a long-way path containing igneous, metamorphic and sedimentary rocks. Brahmaputra (Jamuna) river sediment is found to contain 8%-15% heavy mineral concentration in an average [23,24] which is ultimately contributing to the natural radioactivity. XRD peaks confirmed the presence of quartz, monazite, feldspar, uranium fluoride, rutile, zircon, hematite, kyanite, and uranium arsenide minerals. ...
Article
Full-text available
Distribution of the natural radionuclides (238U, 232Th, and 40K) and their specific activities in sands and sediments of the Brahmaputra (Jamuna) river of Bangladesh together with mineral characteristics has been studied to assess the radiation levels as well as to develop a baseline database for comparison in the future in case of any change in the area under study due to anthropogenic activities. The radiological parameters of natural radioactivity were assessed calculating the radium equivalent activity, hazard index, the absorbed dose rate, and annual effective dose. The average activity concentrations of 226Ra (238U), 232Th, and 40K in sand and sediment were found to be 59 ± 2 & 60 ± 2 Bq/kg, 113 ± 5 & 135 ± 5 Bq/kg, and 983 ± 42 & 1002 ± 43 Bq/kg, respectively. The calculated average absorbed dose rate and annual effective dose were found to be 150 nGy/h and 0.18 mSv/year respectively. These high values are associated with mineral content of the sediment. X‑ray diffraction peaks of sand and sediment samples identify quartz, feldspar, rutile, zircon, monazite, uranium fluoride, hematite, kyanite, and uranium arsenide minerals to be present in the samples.
Article
Full-text available
According to the SNI, the type of concrete for use as nuclear radiation shielding is concrete or mortar that contains hematite, ilmenite, magnetite, barite, or ferrophosphorus synthesis. This study is focused on the characterization of iron sand from and river sand from Papua. The purpose of this research was to determine the specific content of gravity and minerals in iron sand and river sand from Papua. The specific gravities of the sands were measured by manual experiment in a laboratory, while their mineral content were calculated using XRF and SEM - EDS method. The result showed that the specific gravities of iron sand and river sand were 2.66 and 2.50, respectively. The XRF method revealed that the iron sand contained 41.68% Silica, 33.84% Iron, and 24.48% other minerals. The river sand on the other hand contained 58.98% Silica (Si), 26.87% Iron (Fe), and 14.15% other minerals. The SEM -EDS method showed that the iron sand was composed of 39.99 % SiO2, 21.67 % FeO, and, and 38.34 % others; while the river sand contained 39.28% SiO2, 17.45 % FeO, and 43.27 % others. The result showed that both sands have the potentials to be isolated from hematite minerals or magnetite.
Article
Full-text available
The study is carried out to develop a physical separation method for upgradation of valuable minerals from sands of the Someswari River. Understanding the morphology and mineralogy of the heavy minerals may allow development of processing methods that produce the higher grade products. For this purpose, grain size analysis, microscopic, spectroscopic study and feasibility of physical separation by shaking table, electrostatic plate separator and induced roll magnetic separator have been done. Considering the huge quantity of sandy materials of the studied river sands and separation of heavy minerals magnetite, ilmenite and garnet from the bulk sands and further treatment of the light mineral quartz to remove iron coating could be use as glass-sands; either the light mineral quartz or heavy minerals will be the main product. From the overall study by physical separation method, the Someswari River is identified as potential resources for mineral processing.Bangladesh J. Sci. Ind. Res. 50(1), 53-58, 2015
Article
Full-text available
The aim of this paper is to study on the mineralogy, morphology, magnetic property and composition of the sand of Brahmaputra River, Bangladesh. The sand has been collected from randomly selected seven places and separated by High Intensity Rolling Magnetic Separator into three fractions, viz. magnetic, para-magnetic and non-magnetic parts. The identifications of the valuable heavy minerals existing in these fractions have been performed. The valuable heavy minerals in the separated fractions have been counted under reflected and polar-izing microscope and it is found that the magnetic fraction contains ilmenite, magnetite and garnet. The major grain size fraction of the mag-netic fraction is 125 -250 μm (57.18%). Zircon, rutile, xenotime, monazite, sillimanite etc. have been counted in other two fractions. X-ray Diffraction (XRD), X-ray Fluorescence (XRF) and Isodynamic Separator have been applied for mineral assessment and to quantify the rel-ative proportion of mineral species.
Article
Full-text available
The study area Tamiraparani is located between latitudes 8° 25΄ and 9° 13΄ N, and longitudes 77° 10΄ to 78° 10΄ E along the south- east coast of India. All samples were collected between Pre-monsoon July 2003 and Post-monsoon February 2004. The heavy mineral assemblage of the study region is governed by the distribution of different type of minerals. However, the assemblage is dominated by a few selective minerals like garnet (colourless), garnet (pink), zircon, rutile, chlorite, etc. This clearly indicates that in premonsoon period the erosional activities are predominant than the post-monsoon. In both the monsoons, sediments were transported from river and estuary towards the beach and marine regimes. In pre-monsoon whatever sediment deposited were transported and shifted due to longshore current action. But, in the post-monsoon, due to depositional environment whatever the sediments deposited is mainly due to the multi-source like riverine and marine influence is observed.
Chapter
More than 90 percent of the titanium minerals currently produced come from magmatic ilmenite deposits and from young shoreline placer deposits. This means that the two geologic processes most directly responsible for economic titanium-mineral deposits are (1) the accumulation of dense oxide-rich liquids immiscible in cooling magmas of ferrodioritic to gabbroic composition, and (2) the interference between deposition and entrainment in the enrichment of dense minerals on the upper swash zones of beaches (and removal of some concentrates to eolian environments). Both processes are essentially mechanical; i.e., chemical remobilization of titanium does not form its major ore deposits. Both processes also require precursor conditions that ensure that titanium is present predominantly in the form of oxide minerals. In magmatic deposits, these are physical and chemical conditions that favor titanium-oxide over titanium-silicate minerals. In sedimentary deposits, these conditions are a combination of proper source rocks, weathering history, and sedimentary conduits, all necessary to permit the supply of favorable minerals and prevent their dilution with unfavorable ones. Some titanium-mineral production currently comes from fluvial placer deposits (Gbangbama, Sierra Leone) and from deeply weathered alkalic pyroxenites (Tapira, Brazil). In addition, several other deposit types could well become economic in the near future: (1) rutile from eclogites, (2) rutile from contact-metasomatic zones of alkalic anorthosites, (3) perovskite from alkalic pyroxenites, and (4) rutile byproduct from porphyry Cu-Mo deposits; detrital titanium-mineral deposits could be exploited (5) on continental shelves, (6) in Pleistocene glaciolacustrine deltas, or (7) in older, semiindurated beach deposits. If young shoreline placers are depleted, these other deposit types may become important.
Article
The Brahmaputra River of Bangladesh is a potential source of significant amounts of heavy mineral (HM) sand concentrates. This study provides the first ever reported characterisation data for a bulk titanium-rich HM sand sample sourced from the river system. The prepared concentrate contained ∼10-15 wt-% HMs with the remaining 85-90 wt-% of the sample comprising silicate and aluminosilicates. Modal analysis for the Fe- and Ti-rich components indicated that the HM concentrate contained 4·7% primary ilmenite, 4·4% Fe-oxide (magnetite), 0·91% titanomagnetite, 0·94% titanite and 0·08% rutile. Quantitative analysis of the ilmenite component showed the TiO2 content of the ilmenite was within the range 40-52 wt-%TiO2 (average ∼48 wt-%TiO2) with major impurities including MnO (1·83 wt-%) and MgO (0·20 wt-%) and minor impurities being Al2O3 (0·02 wt-%), Cr2O3 (0·03 wt-%), SiO2 (0·08 wt-%) and V2O5 (0·08 wt-%). Based on the composition of ilmenite and current specifications regarding ilmenite compositional purity, the most likely method for processing would be via the sulphate route.
Article
Recent progress in Holocene sea-level studies and studies on coastal evolution in Japan are reviewed. Several studies recorded either a slight fall or slow rise of sea-level in the early Holocene, and some studies recognized minor regressions after the culmination of rapid postglacial transgression. Coastal landforms have changed remarkably during the Holocene. Many drowned valleys were formed in the middle Holocene, and the coast lines in Japan were very rugged at the time. -from Author
Article
Central Kalimantan is an emerging and potentially significant zircon and heavy mineral (HM) province. Characterisation and beneficiation testwork was conducted on two HM alluvial tailings and two zircon-rich concentrates sourced from artisanal production in the Sampit region in Central Kalimantan. The HM assemblage in all samples was dominated by a zircon-rich component. A premium grade zircon product (>66%ZrO2+HfO2 and U+Th<500 ppm) was produced by employing standard electrostatic and magnetic separation procedures. An ilmenite-rich fraction (~59%TiO2) containing minor rutile and leucoxene was also successfully produced as a coproduct. Problem impurities in the ilmenite-rich fraction included significant levels (2.55%) of chromia (Cr2O3) which was concentrated in discrete chrome-bearing spinels. Implications of the mineralogy and chemistry of this fraction for future processing are discussed. No attempt was made to recover the rutile and leucoxene.
Article
Two main sand provinces comprising nearly all the sediments of East Pakistan can be recognized on the basis of their sand mineralogy. One province contains most of the folded Tertiary sedimentary formations bordering East Pakistan in the north, east and southeast as well as old clays, “Madhupur clay”, which occupy extensive terrace-like areas in the centre and west. These sediments are characterized by low contents of feldspars and micas and by high contents of epidote, zircon, tourmaline, kyanite, staurolite and sillimanite in the heavy sand fraction. Except perhaps for the youngest sedimentary formations of this group which are of Pliocene-Early Pleistocene age, the sediments of this main province probably mainly originated from the crystalline rocks of the old Indian peninsula.
Article
The Ganges and Brahmaputra rivers combined have formed one of the largest deltas in the world, comprising some 23,000 sq. miles. These rivers originate within the Himalayan Mountains and drain an enormous land area before entering East Pakistan. Individually, each of the rivers discharges in excess of 2.5 million cusecs of water during flood, and combined they carry nearly 6 million cusecs of water to the Bay of Bengal, nearly three times the amount borne by the Mississippi River. Having such a large drainage area, the rivers are also heavily charged with sediment, transporting approximately 13 million tons of suspended sediment per day during flood. The large discharge and heavy sediment load cause the rivers to be extremely unstable, and the channels are constantly migrating laterally. Within Recent times both rivers have occupied and abandoned numerous river courses. The Brahmaputra followed a route some 60 miles to the east of its present course only 200 years ago. The long-term patterns of river migration indicate that the Ganges has been migrating eastward, whereas the preferred migration of the Brahmaputra is westward. These movements are obviously controlled by major faults or fractures in the earth's crust.