Geography mapping MCQ

Statement A - Spring Tides Spring Tides - 4: Very high tides caused when the Sun, Moon and Earth are almost in the same line. Correct. Spring tides occur when the gravitational forces of the Sun and Moon act together, which happens during the new moon and full moon, when the Sun, Earth and Moon are approximately aligned. Their combined gravitational pull produces a greater tidal range, resulting in higher high tides and lower low tides. Therefore, Spring Tides are correctly matched with 4. Statement B - Neap Tides Neap Tides - 1: Low tides caused when the Sun, Earth and Moon are in the position of quadrature. Correct. Neap tides occur when the Sun and Moon are positioned approximately 90° apart as viewed from Earth, a configuration called quadrature. This occurs during the first-quarter and third-quarter phases of the Moon. The gravitational pulls of the Sun and Moon partially oppose each other, producing a smaller tidal range, with relatively lower high tides and higher low tides. Therefore, Neap Tides are correctly matched with 1. Statement C - Apogean Tides Apogean Tides - 2: Occur when the Moon is the farthest from the Earth. Correct. Apogean tides are associated with the apogee, the point in the Moon's elliptical orbit where it is farthest from Earth. At this point, the Moon's gravitational influence on Earth's oceans is slightly weaker than when it is closest to Earth at perigee. Consequently, tidal ranges can be somewhat smaller. Therefore, Apogean Tides are correctly matched with 2. Statement D - Equinoctial Spring Tides Equinoctial Spring Tides - 3: Tides recurring at an interval of six months. Correct. Equinoctial spring tides occur around the March and September equinoxes, when the Sun is directly over or very close to the equator. The alignment of the Sun's position with the equatorial region, combined with the spring-tide conditions around the new and full moons, can produce particularly high tidal ranges. Since the equinoxes occur approximately six months apart, these tides recur at roughly six-month intervals.

(d) A-3, B-4, C-1, D-2 A. Pacific Ocean \rightarrow 3. Mariana Trench: The Mariana Trench (specifically Challenger Deep) is the deepest point on Earth, reaching a depth of approximately 10,994 meters in the western Pacific Ocean. B. Arctic Ocean \rightarrow 4. Molloy Deep: Located in the Fram Strait west of Svalbard, Molloy Deep is the deepest point in the Arctic Ocean, reaching about 5,550 meters. C. Indian Ocean \rightarrow 1. Sunda Trench: Also known as the Java Trench, this is the deepest point in the Indian Ocean, located in the eastern Indian Ocean near Indonesia at a depth of roughly 7,290–7,450 meters. D. Atlantic Ocean \rightarrow 2. Puerto Rico Trench: Located on the boundary between the Caribbean Sea and the Atlantic Ocean, its deepest feature (Milwaukee Deep) reaches about 8,376 meters.

UPPSC 2022

(C) Only 1, 2 and 4 Ocean salinity refers to the total amount of dissolved inorganic salts (primarily sodium chloride) in seawater, measured in parts per thousand (‰ or ppt). The average salinity of ocean water is approximately 35‰. Salinity increases when pure water is removed or salt is added, and decreases when fresh water is added. 1. Evaporation and Precipitation (Directly Affects Salinity) Evaporation: When seawater evaporates, only pure water vapor ascends into the atmosphere, leaving the dissolved salts behind. This process raises the concentration of salt in the remaining water. For example, the Red Sea has high salinity (~41‰) due to high evaporation rates and limited fresh water influx. Precipitation: Rain, snow, and sleet introduce pure fresh water directly onto the ocean surface. This dilutes the seawater, lowering its salinity. This is why equatorial ocean waters have lower salinity than subtropical waters, despite high solar radiation—heavy daily convectional rainfall constantly dilutes the surface water. 2. Rivers (Directly Affects Salinity) River water is fresh water (containing less than 0.5‰ salinity). When large rivers discharge into oceans or seas, they dilute the coastal salinity significantly. Example: The Bay of Bengal has lower average surface salinity (~30–33‰) than the Arabian Sea (~36–37‰) because major river systems like the Ganga, Brahmaputra, Godavari, Mahanadi, and Krishna continuously empty massive volumes of fresh water into it. 3. Mangrove Vegetation (Does NOT Affect Ocean Salinity) Mangroves are salt-tolerant halophytes (plants) adapted to survive in saline coastal and estuarine zones. While individual mangrove roots employ specialized biological mechanisms (such as ultrafiltration to exclude salt or secretor glands to expel excess salt), they operate as localized ecological consumers within an ecosystem. They do not possess the capacity or scale to alter, dilute, or increase the macro-salinity of the surrounding ocean body. Therefore, vegetation is a consequence of coastal salinity conditions, not an abiotic driver that controls ocean salinity. 4. Ocean Currents (Directly Affects Salinity) Ocean currents act as massive planetary conveyor belts, transporting water masses with distinct salinity and temperature profiles across vast distances. Warm currents carrying high-salinity water from the tropics to higher latitudes elevate the salinity in those northern regions (e.g., the North Atlantic Drift increases salinity along the North European coast). Conversely, cold currents originating from polar regions carry fresher meltwater, lowering salinity along the coasts they traverse.

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(a) Pegmatite - Incorrect Pegmatite is an igneous rock formed from the crystallisation of magma, usually with exceptionally large mineral crystals. It is not the parent rock of quartzite. (b) Limestone - Incorrect Limestone is a sedimentary rock mainly composed of calcium carbonate. When limestone undergoes metamorphism, it generally changes into marble, not quartzite. (c) Sandstone - Correct Sandstone is a sedimentary rock mainly composed of quartz grains. When subjected to intense heat and pressure, its quartz grains recrystallise and become tightly interlocked, forming the metamorphic rock quartzite. Sandstone -> Metamorphism -> Quartzite (d) Shale - Incorrect Shale is a fine-grained sedimentary rock rich in clay minerals. With increasing heat and pressure, shale commonly metamorphoses into slate, then phyllite and schist, rather than quartzite.