English · हिन्दी · తెలుగు · தமிழ் · മലയാളം · मराठी · ಕನ್ನಡ

Glaciers, wind, groundwater and waves

ಕನ್ನಡದಲ್ಲಿ ವಿವರಣೆ

Geomorphology: plates, earthquakes, volcanoes and landforms · Part 4 / 4 · Fact-checked on 8 November 2026 · how we check

Written with AI from the sources listed at the bottom of this page, then fact-checked by a separate AI.

How glaciers carve cirques, arêtes, horns, U-shaped and hanging valleys and fjords and leave moraines, drumlins, eskers and outwash plains; how wind shapes deserts and builds barchans, seif dunes and loess; karst landforms and cave deposits in limestone; and the cliffs, arches, stacks, spits, bars, lagoons and emergent and submergent coasts made by waves.

Each idea is explained first in Kannada (ಕನ್ನಡ), ending with the English and Hindi exam terms, followed by the same point in exam English. UPSC Prelims is in English or Hindi, so understand it in Kannada and revise it in English.

ಭಾಗ 3ರಲ್ಲಿ ಶಿಥಿಲೀಕರಣ ಕಲ್ಲನ್ನು ಸಡಿಲಿಸುವುದನ್ನು, ನದಿಗಳು ಆ ಚೂರುಗಳನ್ನು ಹೊತ್ತೊಯ್ಯುವುದನ್ನು ನೋಡಿದೆವು. ಸವೆತ ಮಾಡುವವರಲ್ಲಿ ನದಿಯೇ ಮುಖ್ಯ, ಆದರೆ ಒಂಟಿಯಲ್ಲ. ಮನೆಯ ಎಲ್ಲ ಕೆಲಸ ಒಬ್ಬರೇ ಮಾಡುವುದಿಲ್ಲವಲ್ಲ — ತಣ್ಣನೆಯ ಬೆಟ್ಟಗಳಲ್ಲಿ ಹಿಮ, ಮರುಭೂಮಿಯಲ್ಲಿ ಗಾಳಿ, ಸುಣ್ಣದಕಲ್ಲಿನ ನೆಲದಲ್ಲಿ ಅಂತರ್ಜಲ, ಕಡಲತೀರದಲ್ಲಿ ಅಲೆಗಳು ಕೆಲಸ ಮಾಡುತ್ತವೆ. ಪ್ರತಿಯೊಂದೂ ನೆಲ ಸವೆಸುತ್ತದೆ, ತಂದದ್ದನ್ನು ಬಿಟ್ಟು ಹೊಸ ರೂಪಗಳನ್ನೂ ಕಟ್ಟುತ್ತದೆ. (→ English: weathering, erosion · हिन्दी: अपक्षय, अपरदन)

In exam EnglishPart 3 showed how weathering loosens rock and how rivers carry the debris away. No agent of erosion works over more of the land than running water, yet others matter too. Where the climate is cold enough for snow to last all year, moving ice takes over; where rain is scarce and plants are few, wind becomes important; where the rock is limestone, water working underground dissolves whole landscapes; and along every coast, waves attack the land. Each both wears land away and builds new landforms from what it drops.

ಹಿಮನದಿ ಎಂದರೆ ಅನೇಕ ವರ್ಷ ಒತ್ತಲ್ಪಟ್ಟ ಹಿಮ ಗಟ್ಟಿ ಮಂಜುಗಡ್ಡೆಯಾಗಿ, ತನ್ನ ಭಾರದಿಂದಲೇ ನಿಧಾನವಾಗಿ ಸರಿಯುವ ದೊಡ್ಡ ಹಿಮರಾಶಿ. ಎರಡು ಬಗೆ: ಇಡೀ ಭೂಖಂಡ ಮುಚ್ಚುವವು (ಅಂಟಾರ್ಕ್ಟಿಕಾ, ಗ್ರೀನ್‌ಲ್ಯಾಂಡ್), ಕಣಿವೆಗಳಲ್ಲಿ ನಿಧಾನವಾಗಿ ಹರಿಯುವ ಮಂಜುಗಡ್ಡೆಯ ನದಿಗಳಂತಹವು (ಸಿಯಾಚಿನ್, ಗಂಗೋತ್ರಿ). ಗಂಗೋತ್ರಿಯಿಂದ ಭಾಗೀರಥಿಗೆ ನೀರು. ಇದು ಕಲ್ಲುಗಳನ್ನು ಹಿಡಿದು ಕೀಳುತ್ತದೆ, ತಳದಲ್ಲಿ ಸಿಕ್ಕಿದ ಕಲ್ಲುಗಳಿಂದ ನೆಲ ಕೆರೆಯುತ್ತದೆ — ಉಪ್ಪುಕಾಗದದಿಂದ ಮರ ಉಜ್ಜಿದಂತೆ. ನದಿ ಕಿರಿದಾದ ಕಾಲುವೆ ಕೊರೆದರೆ, ಇದು ಇಡೀ ಕಣಿವೆಯನ್ನೇ ಕೆತ್ತುತ್ತದೆ. (→ English: glacier · हिन्दी: हिमनद)

In exam EnglishA glacier is a body of ice built up from years of packed snow, heavy enough that its own weight makes it creep downhill or spread outward. Continental glaciers, or ice sheets, bury entire landmasses; today only Antarctica and Greenland carry them. Valley or mountain glaciers flow down valleys like slow rivers of ice; the Siachen and Gangotri glaciers of the Himalaya are examples, and meltwater from Gangotri forms the Bhagirathi, one of the source streams of the Ganga. Ice erodes in two main ways. It freezes onto loosened blocks and pulls them out as it moves (plucking), and the rock fragments frozen into its base scrape and polish the bed beneath (abrasion). Because ice is solid and thick, it erodes the whole valley floor and sides, not just a narrow channel as a river does.

ಹಿಮನದಿ ಎತ್ತರದ ಬೆಟ್ಟಗಳಲ್ಲಿ ವಿಶೇಷ ರೂಪಗಳನ್ನು ಕೆತ್ತುತ್ತದೆ. ಕಣಿವೆಯ ತಲೆಯಲ್ಲಿ ಆರಾಮಕುರ್ಚಿ ಆಕಾರದ ತಗ್ಗು (ಸರ್ಕ್) — ಹಿಮ ಕರಗಿದಾಗ ಅದರಲ್ಲಿ ಪುಟ್ಟ ಕೆರೆ. ಎರಡು ತಗ್ಗುಗಳು ಎದುರುಬದುರಾಗಿ ಕೊರೆದರೆ ನಡುವೆ ಚಾಕುವಿನ ಅಂಚಿನಂತಹ ಏಣು (ಅರೇಟ್). ಮೂರು-ನಾಲ್ಕು ಕಡೆಯಿಂದ ಕೊರೆದರೆ ಚೂಪಾದ ಶಿಖರ (ಹಾರ್ನ್) — ಆಲ್ಪ್ಸ್‌ನ ಮ್ಯಾಟರ್‌ಹಾರ್ನ್. ನದಿಯ 'V' ಕಣಿವೆಯನ್ನು ಇದು ಅಗಲವಾದ 'U' ಮಾಡುತ್ತದೆ. ಸಣ್ಣ ಪಕ್ಕದ ಕಣಿವೆಗಳು ಮೇಲೆ ನೇತಾಡಿ ಜಲಪಾತಗಳಾಗಿ ಕೊನೆಗೊಳ್ಳುತ್ತವೆ. ಸಮುದ್ರದಲ್ಲಿ ಮುಳುಗಿದ 'U' ಕಣಿವೆ ಫಿಯಾರ್ಡ್ — ನಾರ್ವೆ. (→ English: glacier · हिन्दी: हिमनद)

In exam EnglishAt the head of a valley glacier, ice deepens a hollow into the mountainside to form a cirque, a steep-walled, armchair-shaped basin that often holds a small lake, a tarn, after the ice melts. When two cirques eat into a mountain from opposite sides, the wall left between them is whittled into a thin, sharp ridge called an arête. When cirques eat into a single mountain from three or more sides, what remains is a sharp, pyramid-shaped summit known as a horn; the Matterhorn in the Alps is the textbook example. Lower down, the glacier widens and deepens a river's V-shaped valley into a U-shaped trough with a broad floor and steep sides. Side valleys whose smaller glaciers could not cut as deep are left hanging high above the main valley; these hanging valleys often end in waterfalls. Where a glacial trough reaches the coast and is drowned by the sea, it becomes a fjord, a long, deep inlet such as those of Norway.

ಹಿಮನದಿ ನುಣ್ಣನೆಯ ಹುಡಿಯಿಂದ ಮನೆಯಷ್ಟು ದೊಡ್ಡ ಬಂಡೆಗಳವರೆಗೆ ಹೊತ್ತು, ಕರಗುವಲ್ಲಿ ಬಿಡುತ್ತದೆ. ಜರಡಿ ಹಿಡಿಯದ ಈ ಮಿಶ್ರಣ ಟಿಲ್; ಅದರ ದಿಬ್ಬಗಳು ಮೊರೇನ್. ಬದಿಗಳಲ್ಲಿ ಪಾರ್ಶ್ವ ಮೊರೇನ್, ಎರಡು ಹಿಮನದಿಗಳು ಸೇರುವಲ್ಲಿ ಮಧ್ಯದಲ್ಲಿ, ಹಿಮ ಕೊನೆಗೆ ತಲುಪಿದಲ್ಲಿ ಅಂತ್ಯ ಮೊರೇನ್, ತಳದಲ್ಲಿ ಹರಡಿದ್ದು ತಳ ಮೊರೇನ್. ಮೊಟ್ಟೆ ಆಕಾರದ ದಿಣ್ಣೆಗಳು ಡ್ರಮ್ಲಿನ್; ಹಿಮದ ಕೆಳಗಿನ ಸುರಂಗಗಳಲ್ಲಿ ಹರಿದ ನೀರು ಬಿಟ್ಟ ಅಂಕುಡೊಂಕಾದ ಏಣುಗಳು ಎಸ್ಕರ್. ಹೊರಗೆ ಹರಿಯುವ ನೀರು ಮರಳನ್ನು ಜರಡಿ ಹಿಡಿದು ಹರಡಿದಂತೆ ಬಯಲು ಮಾಡುತ್ತದೆ. (→ English: moraine · हिन्दी: हिमोढ़)

In exam EnglishIce carries huge loads of debris, from fine rock flour to boulders, and drops it where it melts. This unsorted debris is called till, and ridges or sheets of till are called moraines. A lateral moraine forms along each side of a valley glacier; where two glaciers meet, their inner lateral moraines join as a medial moraine down the middle; a terminal moraine marks the farthest point the ice reached; and a ground moraine is the uneven sheet of till left on the valley floor as the ice retreats. Ice sheets also shape till into drumlins, smooth oval hills whose blunt end faces the direction the ice came from. Streams of meltwater running through tunnels beneath the glacier deposit long, snaking ridges of sand and gravel known as eskers, while streams issuing from the front of the ice spread sorted sand and gravel across a wide outwash plain.

ಗಾಳಿ ಸಡಿಲ, ಒಣ ಮರಳನ್ನು ಮಾತ್ರ ಎತ್ತಬಲ್ಲದು; ಆದ್ದರಿಂದ ಗಿಡ ಕಡಿಮೆ ಇರುವ ಮರುಭೂಮಿಯಲ್ಲಿ ಅದು ದೊಡ್ಡ ಸವೆತ ಶಕ್ತಿ. ಮೊರದಲ್ಲಿ ಕೇರಿ ಹೊಟ್ಟು ಊದಿದಂತೆ ಮರಳು ಹಾರಿಸುವುದರಿಂದ ಆಳವಿಲ್ಲದ ತಗ್ಗುಗಳು. ಮರಳಿನಿಂದ ಕಲ್ಲನ್ನು ಉಜ್ಜುವುದು — ಭಾರದ ಮರಳು ನೆಲದ ಹತ್ತಿರವೇ ಹಾರುತ್ತದೆ, ಹಾಗಾಗಿ ಕಲ್ಲಿನ ಕೆಳಭಾಗ ತೆಳುವಾಗಿ ಅಣಬೆ ಕಲ್ಲು ಆಗುತ್ತದೆ. ಸುತ್ತಲಿನ ನೆಲ ಸವೆದು ಒಂಟಿಯಾಗಿ ನಿಂತ ಗಟ್ಟಿ ಬೆಟ್ಟ ಇನ್ಸೆಲ್‌ಬರ್ಗ್ (ಉಲುರು). ಬೆಟ್ಟದ ಬುಡದ ಇಳಿಜಾರು ಕಲ್ಲುನೆಲ ಪೆಡಿಮೆಂಟ್; ಮಳೆಯ ನಂತರ ತುಂಬಿ, ಆವಿಯಾಗಿ ಉಪ್ಪಿನ ಪದರ ಬಿಡುವ ತಗ್ಗು ಪ್ಲಾಯಾ. (→ English: erosion · हिन्दी: अपरदन)

In exam EnglishWind can move only loose, dry particles, so it is a major agent of erosion mainly in deserts, where plants are sparse and sand is plentiful. Deflation is the lifting and blowing away of loose material, which can scoop out shallow basins called deflation hollows. Abrasion is the sand-blasting of rock by grains the wind carries; because the heaviest grains travel close to the ground, rock is cut fastest near its base, which can leave a mushroom rock, a cap of rock perched on a narrower stem. Rare but violent sheet floods also shape deserts. An inselberg is a lone, steep hill of resistant rock that remains standing on a plain once the surrounding land has been eroded away; Uluru in Australia is often cited. Pediments are gently sloping rock surfaces at the foot of desert mountains, and playas are flat basins that hold shallow lakes after rain and leave a crust of salt when the water evaporates.

ಗಾಳಿಯ ವೇಗ ಕಡಿಮೆಯಾದರೆ ಅಥವಾ ಅಡ್ಡಿ ಬಂದರೆ ಮರಳನ್ನು ಬಿಡುತ್ತದೆ — ಅದೇ ಮರಳು ದಿಬ್ಬ. ಗಾಳಿಯ ಕಡೆಯ ಮೆಲ್ಲನೆಯ ಇಳಿಜಾರು ಹತ್ತಿ, ಆಚೆಯ ಕಡಿದಾದ ಮುಖದಲ್ಲಿ ಜಾರುತ್ತದೆ; ಹಾಗಾಗಿ ದಿಬ್ಬ ಗಾಳಿಯ ದಿಕ್ಕಿನಲ್ಲಿ ಸರಿಯುತ್ತದೆ. ಅರ್ಧಚಂದ್ರಾಕಾರ, ಕೊಂಬುಗಳು ಗಾಳಿ ಹೋಗುವ ಕಡೆ — ಬರ್ಕಾನ್ (ಗಾಳಿ ಒಂದೇ ದಿಕ್ಕು, ಮರಳು ಕಡಿಮೆ). ಗಾಳಿಗೆ ಸಮಾಂತರವಾದ ಉದ್ದ ಏಣುಗಳು — ಸೀಫ್. ಥಾರ್ ಮರುಭೂಮಿಯಲ್ಲಿ ಅನೇಕ ದಿಬ್ಬಗಳು. ಅತಿ ನುಣ್ಣನೆಯ ಧೂಳು ದೂರ ಹಾರಿ ಲೋಯೆಸ್ ಆಗಿ ಶೇಖರವಾಗುತ್ತದೆ — ಚೀನಾದ ಪ್ರಸ್ಥಭೂಮಿ; ಫಲವತ್ತು, ಆದರೆ ಗಿಡ ಹೋದರೆ ಸುಲಭವಾಗಿ ಕೊಚ್ಚಿಹೋಗುತ್ತದೆ. (→ English: sand dune, loess · हिन्दी: बालुका स्तूप, लोएस)

In exam EnglishWhen wind slows down or meets an obstacle, it drops its sand, and the commonest result is a sand dune. Sand is pushed up a dune's gentle windward slope and slides down its steeper sheltered face, so the dune creeps downwind. Its shape depends on how much sand there is and how steady the wind is. A barchan is a dune shaped like a crescent moon, with its two tips trailing downwind; barchans form where the wind blows mostly from one direction and sand is limited. Seif or longitudinal dunes are long, narrow ridges that run parallel to the main wind direction. The Thar Desert of Rajasthan has extensive fields of dunes of several kinds. The finest particles, silt, can be carried far beyond the desert and settle as loess, a thick, fine-grained, yellowish deposit. The Loess Plateau of northern China is the best-known example; loess makes fertile soil but erodes very easily once its plant cover is removed.

ಸುಣ್ಣದಕಲ್ಲಿನ ನೆಲದಲ್ಲಿ ಅಂತರ್ಜಲ ಅದ್ಭುತ ಮಾಡುತ್ತದೆ. ಮಳೆನೀರು ಗಾಳಿ, ಮಣ್ಣಿನಿಂದ ಕಾರ್ಬನ್ ಡೈಆಕ್ಸೈಡ್ ಹೀರಿ ದುರ್ಬಲ ಆಮ್ಲವಾಗುತ್ತದೆ — ನಿಂಬೆರಸದಲ್ಲಿ ಸುಣ್ಣ ಕರಗಿದಂತೆ ಕಲ್ಲನ್ನು ಕರಗಿಸುತ್ತದೆ. ಬಿರುಕುಗಳು ದೊಡ್ಡದಾಗಿ ಕಾಲುವೆ, ಗುಹೆಗಳಾಗುತ್ತವೆ; ಇಂತಹ ನೆಲ ಕಾರ್ಸ್ಟ್ ಭೂಲಕ್ಷಣ (ಸ್ಲೊವೇನಿಯಾದ ಪ್ರದೇಶದ ಹೆಸರು). ಮೇಲೆ ಆಲಿಕೆ ಆಕಾರದ ತಗ್ಗುಗಳು (ಸಿಂಕ್‌ಹೋಲ್), ತೊರೆ ಮಾಯವಾಗುವ ರಂಧ್ರ (ಸ್ವಾಲೋ ಹೋಲ್) — ಹಾಗಾಗಿ ಮೇಲೆ ನದಿಗಳು ಕಡಿಮೆ. ತಗ್ಗುಗಳು ಸೇರಿದರೆ ಉವಾಲಾ, ಚಪ್ಪಟೆ ತಳದ ದೊಡ್ಡ ತಗ್ಗು ಪೋಲ್ಯೆ. (→ English: karst topography · हिन्दी: कार्स्ट स्थलाकृति)

In exam EnglishGroundwater does its most striking work in limestone and dolomite. Rain that has absorbed carbon dioxide on its way through the air and the soil becomes mildly acidic (carbonic acid), and this acid slowly eats away calcium carbonate; this is the carbonation met in Part 3. Over long periods the water widens joints and cracks into channels and caves, and a landscape dominated by this dissolving action is called karst topography, after the Karst (Kras) region on the border of Slovenia and Italy. On the surface, the first sign is the sinkhole, a funnel-shaped hollow formed where the rock dissolves from below or the roof of a cavity collapses. A swallow hole is an opening through which a surface stream disappears underground, so karst areas often have few surface rivers. Neighbouring sinkholes may merge into a larger depression called an uvala, and the largest closed basins, with flat floors that may stretch for kilometres, are called poljes.

ಗುಹೆಗಳನ್ನು ಕೊರೆದ ನೀರೇ ಅವನ್ನು ಅಲಂಕರಿಸುತ್ತದೆ. ಚಾವಣಿಯಿಂದ ತೊಟ್ಟಿಕ್ಕುವ ಹನಿ ಗಾಳಿ ತಾಗುತ್ತಲೇ ಕಾರ್ಬನ್ ಡೈಆಕ್ಸೈಡ್ ಕಳೆದುಕೊಂಡು, ಕರಗಿದ ಸುಣ್ಣ ಹಿಡಿದಿಡಲಾರದೆ ಪುಟ್ಟ ಉಂಗುರವಾಗಿ ಬಿಡುತ್ತದೆ. ಸಾವಿರಾರು ವರ್ಷಗಳಲ್ಲಿ ಚಾವಣಿಯಿಂದ ನೇತಾಡುವ ಮೇಣದಬತ್ತಿಯಂತಹ ಕಂಬ — ಸ್ಟಾಲಕ್ಟೈಟ್. ಕೆಳಗೆ ಬಿದ್ದ ಹನಿಗಳು ನೆಲದಿಂದ ಮೇಲೇರುವ ಸ್ಟಾಲಗ್ಮೈಟ್ ಕಟ್ಟುತ್ತವೆ. ಎರಡೂ ಸೇರಿದರೆ ಕಂಬ. ಬೊರ್ರಾ ಗುಹೆಗಳು, ಬೇಲಂ ಗುಹೆಗಳು (ಆಂಧ್ರಪ್ರದೇಶ), ಮೇಘಾಲಯದ ಗುಹೆಗಳು ಉದಾಹರಣೆ. (→ English: stalactite, stalagmite · हिन्दी: आश्चुताश्म, निक्षेपाश्म)

In exam EnglishBelow ground, the same water that hollows out caves also decorates them. When water seeping through the roof of a cave reaches the open air of the cave, it loses some of its dissolved carbon dioxide and can no longer hold all its calcium carbonate, so a tiny ring of calcite is left behind with each drop. Over millennia these rings build a stalactite, an icicle-like column hanging from the ceiling. Water that drips onto the floor deposits calcite there too, building a stalagmite that rises upward from the ground. When a stalactite and a stalagmite meet, they form a pillar or column. Among India's limestone caves are Borra in the Eastern Ghats and Belum, both in Andhra Pradesh, along with the long cave networks of Meghalaya.

ಕಡಲತೀರದಲ್ಲಿ ಅಲೆಗಳೇ ಮುಖ್ಯ ಸವೆತ ಶಕ್ತಿ. ಸುತ್ತಿಗೆಯಿಂದ ಮತ್ತೆ ಮತ್ತೆ ಬಡಿದಂತೆ ಅವು ನೀರು, ಮರಳು, ಉರುಟುಕಲ್ಲುಗಳನ್ನು ಬಂಡೆಗೆ ಎಸೆಯುತ್ತವೆ. ಗಟ್ಟಿ ಬಂಡೆಯ ಕೆಳಭಾಗ ಕೊರೆಯಲ್ಪಟ್ಟು ಮೇಲ್ಭಾಗ ಕುಸಿದರೆ ಕಡಿದಾದ ಕಡಲ ಬಂಡೆಗೋಡೆ (ಕ್ಲಿಫ್). ಅದು ಹಿಂದೆ ಸರಿದಾಗ ತಳದಲ್ಲಿ ಚಪ್ಪಟೆ ಕಲ್ಲಿನ ಜಗಲಿ ಉಳಿಯುತ್ತದೆ. ಅಲೆಗಳು ದುರ್ಬಲ ಜಾಗದಲ್ಲಿ ಗುಹೆ ಕೊರೆಯುತ್ತವೆ; ಗುಹೆ ಆಚೆ ತೂರಿದರೆ ಸೇತುವೆಯಂತಹ ಕಮಾನು; ಅದರ ಚಾವಣಿ ಬಿದ್ದರೆ ಸಮುದ್ರದಲ್ಲಿ ಒಂಟಿ ಕಂಬ (ಸ್ಟ್ಯಾಕ್). ಇವೆಲ್ಲ ಒಂದೇ ಕಥೆಯ ಸರಣಿ ಹಂತಗಳು. (→ English: erosion · हिन्दी: अपरदन)

In exam EnglishAlong the coast, waves are the main agent of erosion. Breaking against the shore, they hurl water, sand and pebbles at the rock. Where the land meets the sea in hard rock, waves undercut the base of the slope until the rock above collapses, forming a steep sea cliff. The cliff keeps retreating landward, leaving at its base a gently sloping shelf of rock, the wave-cut platform, which low tide may uncover. Waves attack lines of weakness in a headland first, hollowing out sea caves. If two caves on either side of a headland meet, or one cave cuts right through, a sea arch is formed; when the roof of the arch falls, the seaward part is left standing alone as a stack, which is in turn worn down to a stump. Cliffs, caves, arches and stacks are thus stages in one sequence.

ಅಲೆಗಳ ರಭಸ ಕಡಿಮೆಯಾಗುವಲ್ಲಿ — ಶಾಂತ ಕೊಲ್ಲಿಗಳಲ್ಲಿ — ನಿಕ್ಷೇಪಣ ನಡೆಯುತ್ತದೆ. ನಮಗೆ ಗೊತ್ತಿರುವ ಕಡಲ ಮರಳದಂಡೆ ಅದೇ. ತೀರದುದ್ದಕ್ಕೂ ಹರಿಯುವ ಪ್ರವಾಹ ಮರಳನ್ನು ಪಕ್ಕಕ್ಕೆ ತಳ್ಳುತ್ತ, ಒಂದು ತುದಿ ನೆಲಕ್ಕೆ ಅಂಟಿ ಇನ್ನೊಂದು ತುದಿ ಸಮುದ್ರಕ್ಕೆ ಚಾಚುವ ಮರಳಿನ ನಾಲಿಗೆ (ಸ್ಪಿಟ್) ಕಟ್ಟುತ್ತದೆ. ಕೊಲ್ಲಿಯ ಬಾಯಿಯನ್ನು ಪೂರ್ತಿ ಮುಚ್ಚಿದರೆ ಅದು ಬಾರ್; ಹಿಂದೆ ಸಿಕ್ಕಿದ ಶಾಂತ ನೀರು ಲಗೂನ್ — ಕೆರೆಗೆ ಏರಿ ಕಟ್ಟಿದಂತೆ. ದ್ವೀಪವನ್ನು ನೆಲಕ್ಕೆ ಜೋಡಿಸುವ ಮರಳ ಏಣು ಟೊಂಬೊಲೊ. ಚಿಲಿಕಾ (ಒಡಿಶಾ), ಪುಲಿಕಾಟ್ (ಆಂಧ್ರ–ತಮಿಳುನಾಡು ಗಡಿ), ಕೇರಳದ ಹಿನ್ನೀರು ಉದಾಹರಣೆ. (→ English: deposition, lagoon · हिन्दी: निक्षेपण, लैगून)

In exam EnglishWhere waves lose energy, in sheltered bays or along gently sloping shores, deposition dominates. A beach, a strip of sand or pebbles shifted by the waves, is the most familiar form. Currents running along the shore carry sand sideways, and where the coastline changes direction they can build a spit, a ridge of sand or shingle attached to the land at one end and projecting into the sea at the other. If a ridge grows across the mouth of a bay and closes it, it is called a bar, and the sheltered water trapped behind it becomes a lagoon. A sand ridge that links an island to the mainland is called a tombolo. India's east coast has some of the largest lagoons in the country: Chilika Lake in Odisha, the biggest brackish-water lagoon in India, is separated from the Bay of Bengal by a long sandbar, and Pulicat Lake lies on the Andhra Pradesh–Tamil Nadu border. The backwaters of Kerala, including Vembanad Lake, are also lagoons cut off behind sand bars.

ತೀರಗಳು ನೆಲ ಮತ್ತು ಸಮುದ್ರ ಮಟ್ಟದ ಬದಲಾವಣೆಗಳನ್ನೂ ತೋರಿಸುತ್ತವೆ. ನೆಲ ಮೇಲೆದ್ದರೆ ಅಥವಾ ಸಮುದ್ರ ಇಳಿದರೆ — ಉನ್ಮಜ್ಜಿತ ತೀರ: ನೇರ, ನಯವಾದ, ಅಗಲ ಮರಳದಂಡೆಗಳು, ಲಗೂನ್‌ಗಳು, ನೈಸರ್ಗಿಕ ಬಂದರುಗಳು ಕಡಿಮೆ. ನೆಲ ಕುಸಿದರೆ ಅಥವಾ ಸಮುದ್ರ ಏರಿದರೆ — ನಿಮಜ್ಜಿತ ತೀರ: ಕಣಿವೆಗಳು ಮುಳುಗಿ ಅಂಕುಡೊಂಕಾದ ತೀರ, ರಿಯಾಗಳು, ಫಿಯಾರ್ಡ್‌ಗಳು, ಒಳ್ಳೆಯ ನೈಸರ್ಗಿಕ ಬಂದರುಗಳು. ಬಕೆಟ್‌ಗೆ ನೀರು ಸುರಿದಾಗ ಗೋಡೆಯ ಗೆರೆಗಳು ಮುಳುಗುವಂತೆ ಯೋಚಿಸಿ. ನಮ್ಮ ಪೂರ್ವ ತೀರವನ್ನು ಉನ್ಮಜ್ಜಿತ, ಪಶ್ಚಿಮ ತೀರವನ್ನು ಹೆಚ್ಚಾಗಿ ನಿಮಜ್ಜಿತ ಎನ್ನುತ್ತಾರೆ. (→ English: emergent coast, submergent coast · हिन्दी: निर्गत तट, निमग्न तट)

In exam EnglishCoasts also record changes in the level of land and sea. An emergent coast forms where the land has risen or the sea has fallen. Such coasts tend to be straight and smooth, with wide beaches, offshore bars and lagoons and few natural harbours. A submergent coast forms where the land has sunk or the sea has risen, drowning the lower parts of valleys. Such coasts are indented and irregular: drowned river valleys called rias, drowned glacial troughs called fjords, and deep inlets that make good natural harbours. In Indian geography the broad eastern coastal plain, with its deltas and lagoons, is normally treated as an emergent coast, while the narrower western plain is seen as mostly submerged.

ಒಟ್ಟಾಗಿ ನೋಡಿದರೆ — ನದಿಯಂತೆಯೇ ಪ್ರತಿ ಶಕ್ತಿಯೂ ಬಲ ಇರುವಲ್ಲಿ ಸವೆಸುತ್ತದೆ, ಬಲ ಕುಗ್ಗಿದಲ್ಲಿ ಬಿಡುತ್ತದೆ. ಹಿಮನದಿ ಮೇಲೆ ಸರ್ಕ್, 'U' ಕಣಿವೆ ಕೆತ್ತಿ ಕೆಳಗೆ ಮೊರೇನ್ ಬಿಡುತ್ತದೆ; ಗಾಳಿ ಮರುಭೂಮಿ ಕೆರೆದು ದಿಬ್ಬ ಪೇರಿಸುತ್ತದೆ; ಸುಣ್ಣದಕಲ್ಲು ಕರಗಿಸುವ ನೀರು ಮೇಲೆ ಕಾರ್ಸ್ಟ್ ಭೂಲಕ್ಷಣ, ಕೆಳಗೆ ಗುಹೆ ಮಾಡುತ್ತದೆ; ಅಲೆಗಳು ಕಲ್ಲಿನ ತೀರದಲ್ಲಿ ಕ್ಲಿಫ್ ಕೊರೆದು, ಶಾಂತ ನೀರಿನಲ್ಲಿ ಮರಳದಂಡೆ ಕಟ್ಟುತ್ತವೆ. ಒಳಗಿನ ಶಕ್ತಿಗಳು ನೆಲ ಎತ್ತಿದರೆ, ಬಹಿರ್ಜನ್ಯ ಬಲಗಳು ಅದನ್ನು ಸವೆಸಿ ಮತ್ತೆ ರೂಪಿಸುತ್ತವೆ — ಕುಂಬಾರ ಮಣ್ಣು ಪೇರಿಸಿ ಚಕ್ರದಲ್ಲಿ ರೂಪ ಕೊಡುವಂತೆ. (→ English: glacier, moraine, karst topography, exogenic forces · हिन्दी: हिमनद, हिमोढ़, कार्स्ट स्थलाकृति, बहिर्जात बल)

In exam EnglishTaken together, ice, wind, groundwater and waves repeat the pattern that rivers showed in Part 3: each agent erodes where it has energy and deposits where it loses it. A glacier carves cirques, horns and U-shaped valleys high up and drops moraines, drumlins and outwash lower down; wind scours deserts and piles sand into dunes; water dissolving limestone produces karst topography above ground and caves below; and waves cut cliffs and stacks on rocky headlands while building beaches, spits and lagoons in quieter water. With this part the chapter is complete: relief is raised by endogenic forces, through plate movement, earthquakes and volcanoes, and is lowered and remodelled by exogenic forces, so that every landscape is a balance between the two.

Landforms made by ice, wind, groundwater and waves
Agent	Where it dominates	Erosional landforms	Depositional landforms
Glaciers	High mountains, polar regions	Cirque, arête, horn, U-shaped valley, hanging valley, fjord	Moraines, drumlins, eskers, outwash plain
Wind	Deserts	Deflation hollow, mushroom rock, inselberg (with sheet floods), pediment	Barchans, seif dunes, loess
Groundwater	Limestone and dolomite (karst)	Sinkhole, swallow hole, uvala, polje, cave	Stalactite, stalagmite, pillar
Waves	Coasts	Cliff, wave-cut platform, sea cave, arch, stack	Beach, spit, bar, tombolo, lagoon

Exam traps

Cirques, arêtes, horns and U-shaped valleys are erosional; moraines, drumlins, eskers and outwash plains are depositional. Questions mix the two lists.
Till (moraine material) is unsorted; outwash and eskers are sorted by meltwater. Do not call a moraine 'sorted'.
A drumlin's high, blunt end faces the direction the ice came from (up-glacier); its long, gentle tail points the way the ice was going (down-glacier).
The tips of a barchan trail downwind, and barchans need a steady one-direction wind and only a thin supply of sand; seif dunes line up along the wind direction, not across it.
Stalactites hang from the ceiling; stalagmites rise from the floor. Both are deposits of calcium carbonate, not erosional features.
A fjord is a drowned glacial valley; a ria is a drowned river valley. Both belong to submergent coasts.
A spit is attached to the land at one end; a bar closes a bay; a tombolo joins an island to the mainland.
Chilika in Odisha is India's largest brackish-water lagoon; Vembanad is in Kerala; Pulicat lies on the Andhra Pradesh–Tamil Nadu border.

Recap

Glaciers erode by plucking and abrasion and shape the whole valley, not a narrow channel.
Glacial erosion: cirque (with tarn), arête, horn, U-shaped valley, hanging valley, fjord.
Glacial deposition: unsorted till in lateral, medial, terminal and ground moraines; drumlins; sorted eskers and outwash plains.
Wind works by deflation and abrasion in deserts: deflation hollows, mushroom rocks; inselbergs, pediments and playas also owe much to sheet floods.
Dunes: barchans (crescent, horns downwind), seif or longitudinal dunes (parallel to wind); loess is fine wind-blown silt (Loess Plateau, China).
Karst forms in limestone by carbonation: sinkholes, swallow holes, uvalas, poljes and caves; stalactites hang, stalagmites rise, pillars join them.
Waves cut cliffs, wave-cut platforms, caves, arches and stacks; they build beaches, spits, bars, tombolos and lagoons (Chilika, Pulicat, Vembanad).
Emergent coasts are smooth with bars and lagoons; submergent coasts are indented with rias and fjords; India's east coast is usually called emergent, the west largely submerged.

Practice questions

Q1. Which one of the following is a landform produced by glacial deposition?

Cirque
Arête
Drumlin
Hanging valley

Show answer

Answer: C. Drumlin

A drumlin is an oval hill moulded from till, so it is depositional. A cirque is a hollow carved at the head of a glacier, an arête is a ridge sharpened between cirques, and a hanging valley is a side valley left high by the deeper erosion of the main glacier; all three are erosional.

Q2. Consider the following statements:
1. Glacial till is a well-sorted deposit laid down by meltwater streams.
2. Eskers are long, winding ridges of sand and gravel deposited by streams flowing beneath a glacier.
Which of the statements given above is/are correct?

1 only
2 only
Both 1 and 2
Neither 1 nor 2

Show answer

Answer: B. 2 only

Statement 1 is wrong: till is dropped directly by ice and is unsorted; sorted deposits come from meltwater (outwash, eskers). Statement 2 is correct. So (a) and (c) accept a wrong statement and (d) rejects a correct one.

Q3. Which name is given to a crescent dune with its tips trailing downwind, usually found where the wind comes mostly from one side and little sand is available?

Seif dune
Barchan
Loess
Playa

Show answer

Answer: B. Barchan

A barchan is the crescent dune with horns pointing downwind. A seif dune is a long ridge parallel to the wind, loess is a sheet of fine wind-blown silt rather than a dune, and a playa is a flat desert basin that holds a shallow lake after rain.

Q4. Match List I (landform) with List II (agent that forms it):
List I
A. Mushroom rock
B. Polje
C. Sea stack
D. Arête
List II
1. Glacier
2. Wind
3. Waves
4. Groundwater
Select the correct answer using the code given below:

A-2, B-4, C-3, D-1
A-3, B-4, C-2, D-1
A-2, B-1, C-3, D-4
A-4, B-2, C-1, D-3

Show answer

Answer: A. A-2, B-4, C-3, D-1

Mushroom rocks are cut by wind abrasion, poljes are large karst basins dissolved by groundwater, stacks are left by waves, and arêtes are ridges between glacial cirques: A-2, B-4, C-3, D-1. Option (b) gives the mushroom rock to waves and the stack to wind; (c) gives the polje to glaciers and the arête to groundwater; (d) is wrong on every pair.

Q5. With reference to limestone caves, consider the following statements:
1. Stalactites grow upward from the floor of a cave.
2. Stalactites and stalagmites are formed by the deposition of calcium carbonate from dripping water.
Which of the statements given above is/are correct?

1 only
2 only
Both 1 and 2
Neither 1 nor 2

Show answer

Answer: B. 2 only

Statement 1 is wrong: stalactites hang from the ceiling; it is stalagmites that rise from the floor. Statement 2 is correct: dripping water loses carbon dioxide and leaves calcite behind. So (a) and (c) accept the wrong statement and (d) rejects the correct one.

Q6. What is the name for a sand bar that connects an island with the mainland?

Spit
Tombolo
Stack
Wave-cut platform

Show answer

Answer: B. Tombolo

A tombolo links an island to the mainland. A spit is attached to land at only one end and ends in open water, a stack is an erosional pillar of rock left by waves, and a wave-cut platform is a rock surface at the foot of a retreating cliff.

Q7. Consider the following pairs:
1. Chilika Lake : Odisha
2. Pulicat Lake : Kerala
3. Vembanad Lake : Tamil Nadu
How many of the pairs given above are correctly matched?

Only one
Only two
All three
None

Show answer

Answer: A. Only one

Only pair 1 is correct. Pulicat lies on the Andhra Pradesh–Tamil Nadu border, not in Kerala, and Vembanad is in Kerala, not Tamil Nadu. So (b) and (c) count wrong pairs as correct, and (d) misses the correct Chilika pair.

Q8. Which of the following features are typical of a submergent coast?
1. Rias
2. Fjords
3. Straight shoreline with offshore bars and few natural harbours
Select the correct answer using the code given below:

1 and 2 only
2 and 3 only
1 and 3 only
1, 2 and 3

Show answer

Answer: A. 1 and 2 only

Rias (drowned river valleys) and fjords (drowned glacial troughs) mark a submergent coast. A straight shoreline with offshore bars and few harbours is typical of an emergent coast, so every option containing 3, namely (b), (c) and (d), is wrong.

← Part 3 All parts Quick recap →

Study this in the Upscore app to keep notes, save it for revision, track your practice scores and follow a plan to the exam date. It's free.

Study this in the app →

Sources

United States Geological Survey: educational material on glaciers and ice sheets, groundwater, and karst and caves (US government) — https://www.usgs.gov/special-topics/water-science-school
US National Park Service, Geologic Resources: glacial, aeolian, karst and coastal landforms (US government) — https://www.nps.gov/subjects/geology/landforms.htm
USGS publication 'Deserts: Geology and Resources' (A. S. Walker): wind erosion, desert landforms and types of dunes (US government) — https://pubs.usgs.gov/gip/deserts/
NOAA National Ocean Service: waves, coastal erosion, beaches, barrier islands and lagoons (National Oceanic and Atmospheric Administration, US government) — https://oceanservice.noaa.gov
Chilika Development Authority, Government of Odisha: Chilika Lake, the largest brackish-water lagoon in India — https://www.chilika.com