The Barind Tract is a Pleistocene physiographic unit covering 7,770 sq km in northwest Bangladesh and parts of West Bengal, India. It consists of reddish clay soils deposited during the last glacial period when monsoon rainfall was heavier and rivers spilled over their banks. The tract is bounded by rivers and separated into units with entrenched dendritic drainage patterns. It underwent uplift and tilting, influencing river courses over time. The Barind Tract is characterized by its elevated terrain, reddish clay soils, and sparser vegetation compared to surrounding floodplains.

1. Barind Tract and its Geological
Evolution

2. Barind Tract
Barind Tract is the largest Pleistocene physiographic unit of the bengal
basin, covering an area of about 7,770 sq. km. It has long been
recognized as a unit of old alluvium, which differs from the surrounding
floodplains. In Bangla, it is spelled and pronounced as Varendra Bhumi.
Geographically this unit lies roughly between latitudes 24'20'N and
25'35'N and longitudes 88'20'E and 89'30'E. It covers most of Dinajpur,
Rangpur, Pabna, Rajshahi, Bogra, and Joypurhat districts of Rajshahi
Division and Rangpur Division in Bangladesh as well as entirety of Uttar
Dinajpur, Dakshin Dinajpur and most of Maldah districts in West

4. This physiographic unit is bounded by the karatoya to the east, the
mahananda to the west, and the northern bank of the ganges to the
South. A lower fault scarp marks the eastern edge of the Barind Tract,
and the little jamuna, atrai and Lower Punarbhaba rivers occupy fault
troughs. The western part of this unit has been tilted up; parts of the
western edge are more than 15m higher than the rest of the tract and the
adjoining Mahananda floodplain. The southern part of the main eastern
block of the Barind Tract is tilted down towards the southwest and
passes under lower Atrai basin sediments in the south.

5. Weather Condition:
Based on rainfall, humidity, temperature and wind pressure the weather
condition is classified into four types, such as,
 pre-monsoon
 monsoon
 post-monsoon and
 winter
Rainfall is comparatively little in this region, the average being about
1,971 mm. It mainly occurs during the monsoon. Rainfall varies from
place to place as well as year to year.

6. This region has already been designated as drought prone. Its average
temperature ranges from 35'C to 25'C in the hottest season and 9'C to
15'C in the coolest season. Generally this region is rather hot and is
considered semi-arid. In summer, some of the hottest days experience a
temperature of about 45'C or even more in Rajshahi area, particularly in
lalpur upazila. In winter it falls to about 5'C in some places of Dinajpur
and Rangpur districts.

7. Physiography
Physiographically this region is divided into three units.
 Recent Alluvial Fan,
 Barind Pleistocene
 Recent Floodplain.
These morphologic units are separated by long, narrow bands of recent
alluvium. The floodplain of the Mahananda flanks the west side while the
Karatoya delineates the eastern margin. The punarbhaba, Atrai and Old
Jamuna with headwaters in the foothills of the Himalayas, Which have cut
across the Pleistocene and their floodplains separate the units.

8. These and numerous other streams are responsible for the development
of a broad Piedmont alluvial plain, which delineates the northern flank
of the Tract. The Tista alluvial fan is located to the north of the area. In
the Barind region, three distinct channel patterns are observed. In the
north there is a great number of small braided streams, which have built
a broad piedmont alluvial plain along the foothills of the Himalayas.
The major rivers of these alluvial plains are the Atrai and the
Punarbhaba, with entrenched valleys. On the Pleistocene unit, there are
numerous small entrenched, tightly meandering streams,

9. which have developed an overall dendritic pattern and flow into the
major north-south rivers of the Barind unit. There are some major
valleys that separate the Pleistocene unit into some north-south
elongated units. These valleys are followed by some major rivers, such
as the Mahananda in the west, the Karatoya in the east, the Atrai and the
Punarbhaba in between. The largest unit is bounded by the river
Punarbhaba and the Atrai. Another large unit is bounded by the Karatoya
and the Little Jamuna. Many small channels, mostly of dendritic pattern,
flow through the individual units.

10. In the Barind region, three distinct channel patterns are observed. In the
north there is a great number of small braided streams, which have built
a broad piedmont alluvial plain along the foothills of the Himalayas. The
major rivers of these alluvial plains are the Atrai and the Punarbhaba,
with entrenched valleys. On the Pleistocene unit, there are numerous
small entrenched, tightly meandering streams, which have developed an
overall dendritic pattern and flow into the major north-south rivers of the
Barind unit.

11. There are some major valleys that separate the Pleistocene unit into some
north-south elongated units. These valleys are followed by some major
rivers, such as the Mahananda in the west, the Karatoya in the east, the
Atrai and the Punarbhaba in between. The largest unit is bounded by the
river Punarbhaba and the Atrai. Another large unit is bounded by the
Karatoya and the Little Jamuna. Many small channels, mostly of
dendritic pattern, flow through the individual units.

12. However, it is very interesting that the course of the Karatoya is
controlled by a southeast trending fault. In the late 17th century, the
major stream of this region was tista which, near Jalpaiguri, branched
and followed the course of the Depa-Punarbhaba to the west, the Atrai
due south and the Little Jamuna to the southeast. All of these rivers
discharged into the Ganges. Of these rivers, the Atrai seems to have been
the major channel in the late 17th century with the Punarbhaba as the
second most important.

13. But now the Tista, Karatoya and Atrai flow into the jamuna
(Brahmaputra). The river courses, particularly of the Tista, changed
suddenly in 1787 during a major flood. This change could have been
accompanied by renewed uplift and tilting of the Barind surface. At the
present time, the Punarbhaba, Atrai and Little Jamuna still carry some
flood flow but they generally can be considered as antecedent streams
carrying mainly local runoff water of the uplifted Barind area.

14. Origin and Evolution of Barind Tract
The Barind is floored by the characteristic of Pleistocene sediments
known as the Madhupur (Barind) Clay. The Madhupur clay is reddish
brown in color, oxidized, sticky and rather compact. JP Morgan and WG
McIntire assumed these deposits to be of fluvial origin. Actually they
were deposited in the late Pleistocene time towards the end of the last
glacial period. Nearly 18,000 years ago, the last glacial period reached
the peak of activities.

15. During that time the sea level dropped to 100m to 130m below the
present-day level. Then the ice-melt water flowed into the Bay of
Bengal. Right at that time the northeast monsoon climatic condition
commenced in the subcontinent. Rainfall was not then dominating the
Bengal plain. Bengal rivers only flowed with ice-melt water through
their narrow and incised valleys. Later, 12,000 years ago, the southwest
monsoon climate started dominating the region, and brought heavy
rainfall over the Bengal Basin.

16. The monsoon rainfall was even more intense than at present. The narrow
Bengal rivers could not discharge this huge quantity of water, supplied by
huge rainfall as well as the ice-melt water from the Himalayan Range. The
rivers spilled over the banks and deposited sediments over the large
Bengal plain washing the sediments to the south where the sediments
prevailed in the Barind Tract and madhupur tract and also in the lalmai
area. Afterwards, climatic conditions started to change, making
temperature rather hot, which readily influenced the Bengal river courses,

17. the sea level started rising again and the depressed regions began getting
more sediments. But these Holocene (Recent time) sediments could not
reach such a height that they would be deposited over the earlier
Madhupur sediments. There is another school of thought that suggests a
tectonic origin for the Pleistocene high terrace. This school says that the
Pleistocene sediments were deposited in large depressions of the Barind
and Madhupur regions. After the deposition due to the neotectonic
movement, these regions uplifted and formed high terraces.

18. Barind Tract Characteristic Distribution
Barind tract is one of the several terraces of Pleistocene age within the
Bengal basin. This tract is characterized by its comparatively high
elevation, reddish and yellowish clay soils (Khiyar in local terminology),
entrenched dendritic stream pattern and a relative paucity of vegetation.
a)North-eastern Outliers: Three separate sections of the barind tract are
surrounded by Tista deposits. These outliers differ from the main tract in
having deep red-brown soils. The sharp edges of parts of these outliers
suggests some block faulting.

19. b)Eastern Barind: This area enclose is roughly 1930.39 sq km and
cover the whole parts of the Upazila of Taras, Singra, Nandigram,
Raninagar, Adamdighi, Kahaloo, Khetlal, Sherpur, Bogra, Dupchanchia,
Shibganj, Panchbibi, Joypurhat, Gobindaganj, Palashbari, Pirganj,
Mithapukur, Badarganj, Saidpur, Parbatipur, Nawabganj, Ghoraghat and
Hakimpur.
c)The East-Central Barind: This part is the narrowest of the four parts,
being only 12 km in average width. Its length is 97 km from
Chirirbandar Upazila to Mahadebpur Upazila. Out of its 676 sq km 507
sq km are in Bangladesh.

20. d)West-Central Barind: This large section of the terrace is 145 km long and
varies from 16 km to 37 km in breadth. About 1770 sq km of it is in
Bangladesh. This part includes a bit of east of the Dinajpur town between the
Kankra and Atrai rivers, almost the whole of Godagari, Tanor, Niamatpur,
Nachole and Porsha Upazila and parts of Dinajpur, Mahadebpur, Gomastapur,
Chapai-Nawabganj and Pabna Upazilas.
e)Western Barind: Four small sections of the western Barind projects into
Bangladesh in Gomastapur and Porsha Upzilas along the Purnabhaba and
Tangon rivers. Though the Tangon does form a small part of the boundary
between India and Bangladesh, its valley ends in Mahananda River flood-plain.