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From south to north, the zones and the major faults separating them are the Main Frontal Thrust (MFT), Subhimalaya Zone (also called Sivalik), Main Boundary Thrust (MBT), Lesser Himalaya (further subdivided into the "Lesser Himalayan Sedimentary Zone (LHSZ) and the Lesser Himalayan Crystalline Nappes (LHCN)), Main Central thrust (MCT), Higher ...
Its lower crust and mantle slid under, but one layer of the upper crust piled up in sheets (called nappes) ahead of the subduction zone. [20] Geophysicist Peter Molnar noted that most of the Himalayas are "slices of rock that once were the top part of India's crust." [21] This is the process of mountain building, or orogeny, in the Himalayas.
Hagen called them Khumbu Nappes, and Lumbasumba Nappes. [19] Arita calls it the Himalayan Gneiss Group, [16] and it lies above the MCT II, or the upper MCT. The High Himalayan Crystalline units (HHC) [20] are mainly composed of kyanite- to sillimanite-grade gneisses intruded by High Himalayan leucogranites at structurally higher levels. [21]
Prominently orogenic belts on the Earth are the circum-Pacific orogenic belt (Pacific Ring of Fire) and Alpine-Himalayan orogenic belt. [5] Since these orogenic belts are young orogenic belts, they form large mountain ranges; crustal activity is active and accompanied by volcanic belts and seismic belts.
Crustal thickening has an upward component of motion and often occurs when continental crust is thrust onto continental crust. Basically nappes (thrust sheets) from each plate collide and begin to stack one on top of the other; evidence of this process can be seen in preserved ophiolitic nappes (preserved in the Himalayas) and in rocks with an inverted metamorphic gradient.
Accretionary orogens, which were produced by subduction of one oceanic plate beneath one continental plate for arc volcanism. They are dominated by calc-alkaline igneous rocks and high-T/low-P metamorphic facies series at high thermal gradients of >30 °C/km. There is a general lack of ophiolites, migmatites and abyssal sediments.
The Himalayan tahr. Because alpine tundra is located in various widely separated regions of the Earth, there is no animal species common to all areas of alpine tundra. Some animals of alpine tundra environments include the kea, marmot, mountain goat, bighorn sheep, chinchilla, Himalayan tahr, yak, snow leopard, and pika. [18]
Annapurna (/ ˌ æ n ə ˈ p ʊər n ə ˌ-ˈ p ɜːr-/; [2] [3] Nepali: अन्नपूर्ण) is a massif in the Himalayas in north-central Nepal that includes one peak over 8,000 metres (26,247 ft), thirteen peaks over 7,000 metres (22,966 ft), and sixteen more over 6,000 metres (19,685 ft). [4]