The Plateau – Meghalaya PCS Free Notes

Geographical location of Meghalaya

January 15, 2018October 4, 2024 by rawan239

Geographical location of Meghalaya

The state of Meghalaya (the abode of clouds) is geographically known as the “Meghalaya Plateau” or the “Shillong Plateau”. The area is made of the oldest rock-formations. Meghalaya consists of the Garo, Khasi and Jaintia hills along with their outliers formed by the Assam ranges. It is the detached north-eastern extension of the Peninsular India. Part of it lies buried under the alluvium deposited by the Ganga-Brahmaputra system of rivers. This gap is known as Malda gap (between Raj Mahal hills/Chhota Nagpur and the Shillong Plateau).

Meghalaya Plateau’s elevation varies between 150 meters to 1961 meters above sea level. The Plateau is highly dissected and has irregular terrain in the western and northern side. The southern side is marked by a continuous escarpment with steep slopes. The broken hills and ranges in the north are not of a well defined boundary.

The western part of the plateau or the Garo hills has an elevation of 600m above sea level. The most important relief feature of this part of the plateau is the Tura range with its highest point at Nokrek 1515 meters above sea level. The central and the eastern part of the plateau or the Khasi and the Jaintia hills district play prominent senile topography. This part of the plateau is characterised by the presence of many peneplained surfaces, flat-topped hills and numerous river valleys. The central upland zone is the most important relief feature of the area and covers more than one-third of the area, east of the Garo hills. The highest point of this part of this plateau and that of the entire state is the Shillong peak whose elevation is about 1965m above sea level. Geographical location of Meghalaya

In the Garo hills, the important rivers of the northern system from west to east are the Kalu, Ringgi, Chagua, Ajagar, Didram, Krishnai and Dudnai. Of these only the Krishnai and Kalu are navigable. The important rivers of the southern system are Daring, Sanda, Bandra, Bhogai, Dareng and Simsang. Simsang is the largest river in the Garo hills and navigable only for about 30 Km. other navigable rivers are Nitai and the Bhupai.

In the central and eastern section of the plateau the important northward flowing rivers are Umkhri, Digaru and Umiam and the south-flowing rivers are Kynchiang (Jadukata), Mawpa, Umiew or Barapani, Myngot and Myntdu.

Relief and structure of Meghalaya

January 15, 2018September 26, 2024 by rawan239

Relief and structure of Meghalaya

Meghalaya is an upland area formed by a detached block of the Deccan plateau. Its summits vary in elevation from 4,000 to 6,000 feet (1,220 to 1,830 metres). The Garo Hills in the west rise abruptly from the Brahmaputra River valley to about 1,000 feet (300 metres) and then merge with the Khasi Hills and Jaintia Hills, adjacent highland systems that form a single massif of tablelands separated by a series of eastward-trending ridges. The southern faces of the plateau, overlooking the Bangladesh lowlands, is particularly steep.

Meghalaya Plateau belongs to the part of Super Continent of Gondwanaland, i.e., the Peninsular table land, but is detached from the latter by the intervening spread of the alluvium of the Ganga and the Brahmaputra. The structural history of the region reveals several phases of erosion, sedimentation, diastrophism, intrusion, movements of land and sea, and emission.

The plateau is mainly made up of rocks of the pre-Cambrian age. The pre-Tertiary and Tertiary rocks occur above these rocks on its western and southern margins. Stratigraphically the rocks of the plateau belong to five broad geological formations, namely the Archaean gneissic complex, the Shillong group of rocks, the lower Gondwana, the Sylhet traps, and Cretaceous – Tertiary – Quarternary Sediment.

The Archaean-gneissic complex occupies the central and northern parts of Meghalaya Plateau. The rocks include gneiss, granite, quartzites, schists, etc. The Shillong group of rocks lying unconformably over the gneissic complex, occurs in the central and eastern parts of the plateau These include phylite, quartzites, schists and conglomerates.

The lower Gondwana rocks are found in the western part of Garo Hills which include pebble beds, sandstones and shale. The Sylhet trap is exposed along the southern border of the Khasi Hills in an east-west direction, and rests unconformably over the eroded pre-Cambrian basement rocks. These rocks are predominantly basalt, rhyolite and acid tuffs.

The Garo Hills region of the State, in its greater portion, is formed of gneissic rocks overlaid by sandstones and 1 conglomerates of Cretaceous-Tertiary system.

The sediments of this system of rocks are known as the Garo group in the region. This group of rocks is again divided into the Simsang, Baghmara and the Chengapara formations. The Simsang is the oldest formation in the Garo group which lies conformably over the Kopili series (the youngest formation of the Jaintia group of Cretaceous – Tertiary sediments), and consists of siitstone and sandstone.

the Baghmara formation includes sand, pebble, conglomerates and clay which lie conformably over the Simsang formation. The Chengapara formation consists of sand, siitstone and clay. On the top of these Cretaceous-Tertiary formations rests limestone of Numulitic age, while sandstones of upper Tertiary origin form low hiiis along the Mymensing border. Relief and structure of Meghalaya

The Khasi Hills are located east of the Garo Hills. The other Khasi tribes did not have princes but their twenty petty states (hima), and sometimes even smaller tribal divisions, are led by one or two Chiefs -selected in various ways- usually styled Siem, Syiem. The names of these chieftainships are : Bhawal, Cherra (or Sohra; capital Cherrapunji), Dwara (capital Hat Dwara), Jirang, Khyri(e)m (capital Cherrapunjee, under a Radja), Langrin, Lungiong, Maharam, Malai Sohmat, Marriw, Mawdon, Mawiang, Mawlong, Mawphlang, Mylliem (including Shillong city, the colonial capital of all Tribal Assam), Nobosohphoh, Noglwai, Nongkhlaw, Nongspung, Nongstoin, Pamsanggut, Rambrai, Shella, Sohiong. or Sardar .

The Jaintia Hills are located further to the east from the Khasi Hills. The twelve Chiefs of the elaka (tribal province) of the Jaintia, a Khasi subtribe of the) Pantars = Syntengs tribes, are styled Dolloi, and the land is called after them in Khasi: KA RI KHADAR DOLLOI ‘Land of 12 Tribal Chiefs‘) – they are in Nartiang itself (see the Raja, uniquely also styled, as premier Chief: U Kongsong), and in Amwi, Jowai, Lakadong, Mynso, Nongbah, Nongjngi, Nongphyllut, Nongtallang, Raliang, Shangpung, Sutnga (see below; also cited as seat of a Syiem) Above them is the only true princely ruler of the area, the Raja of Jaintiapur.

His winter capital is now in Bangladesh, with his summer residence shifted from Sutnga (where the family started as Syiems) to Nartiang; also a palace in the commercial center Borghat. The Jaintia Hills used to be a part of the Jaintia Hills District. The district has been bifurcated into two separate districts,namely, East Jaintia Hills and West Jaintia Hills on 31 July 2012.

Rivers and drainage system of Meghalaya

January 15, 2018September 12, 2024 by rawan239

Rivers and drainage system of Meghalaya

One of the world’s wettest regions is found in Meghalaya. Mawsynram and Cherrapunji (Sohra) in the East Khasi Hills district are geographically considered as the rainiest places in the World. — Cherrapunji, which has an average annual precipitation of about 11,430 mm (450 inches) during monsoon season (from May to September) and Mawsynram, a village directly west of Cherrapunji, where rainfall of around 17,800 mm (700 inches) per year has been recorded. The area receives rainfall on an average for 160 days in a year, spread over 6 to 8 months from March to October.

Physiographically, Meghalaya represents a remanant of an ancient plateau of Pre-Cambrian Peninsular shield, block lifted to its present height and is referred as Meghalaya Plateau or as Shillong-Mikir massif. It is the detached northeastern extension of Indian Peninsular shield, part of which lies beneath the alluvium deposited by Ganga Brahmaputra system of rivers. The rivers of the State are rainfed and therefore their discharge dwindles during summer. Important rivers in Garo Hills region are Daring, Sanda, Bugi, Dareng and Simsang. In the central and eastern part of the plateau are Umkhri, Digaru, Umngot and Myntdu rivers.

The surface water resource is tapped in a number of places by constructing dams across the rivers. The reservoirs, like the Umium and Kopili, so developed are not only used for irrigation and drinking water but also for generating electricity. Inspite of this, the area experiences shortage of water during the summer resulting in crisis for drinking water. This is mainly due to topographical and geomorphological conditions apart from alterations of the natural land surface by way of development, mining and urbanization.

Moreover, the characteristic hilly and steep sloping terrain condition in the area with localized small valleys results in very high surface run-off during the monsoon.

Some of the important rivers of Meghalaya are as follows:

Digaru

Digaru is a river originating in the Garo-Khasi hills of Meghalaya state in India, flowing towards the northeast and then meeting the Kolong river and then merging with the Brahmaputra river. The name Digaru originated from a Kachari/Mech word ‘Di’ which means water and ‘Garo’ means the people living in the Garo hills. Hence Digaru literally means “water of the Garo”.

Kopili River

The Kopili originates in the Meghalaya plateau and flows through southern Assam before its confluence with the Brahmaputra. In Assam it drains the districts of Karbi Anglong, Dima Hasao, Kamrup and Rivers and drainage system of Meghalaya Nagaon. The river flows for a total length of 290 kilometres (180 mi) and has a catchment area of 16,420 square kilometres (6,340 sq mi). It is noted for several spectacular waterfalls along its course which has several deep gorges and rapids in the 120 kilometres (75 mi) of its flow before debouching into the plains at Nagaon district.

Myntdu River

Myntdu River is one of the major water bodies in Jaintia Hills District, Meghalaya, locally known as ‘ka Tawiar ka Takan’ (Our Guardian Angel) in the Pnar dialect. It is a blessing to the residents of the town of Jowai and adjacent places. Its abundant water is used to irrigate the Myntdu Valley, located on the outskirts of Jowai town. The river, originating at 1,420 metres (4,660 ft) above sea level, is fit for hydro-power development.

The river flows across Jowai, and then through Leshka (where a Hydro Project Dam is being constructed) to reach a village Borghat, within Jaintia Hills, before finally entering Bangladesh, where it is locally called ‘Shari’.

Piyain River

Piyain River a trans-boundary river of India and Bangladesh. It is a tributary of the Surma river, which is originates from the Umgat river of Assam. The river enters Bangladesh through Sylhet district. The length of the river is 145 km. Piyain river has emerged from the river om or Umagat river or Assam.

Someshwari River

Someshwari River, known as Simsang River in the Indian state of Meghalaya, is a major river in the Garo Hills of Meghalaya and Netrakona District of Bangladesh. It divides the Garo Hills into two parts.