Monday, December 15, 2008

Geology, soils, gemstones and weather of Afghanistan

Afghanistan's mountain ranges developed in the alpine Orogeny, though some traces of previ-ous uplifts had also survived. During the orogenic movements the area was wedged between the rigid blocks of central-Asiatic Hercynides in the north and Precambrian blocks of India in the south. The geological structure of the mountains is very complex; both Palaeozoic rocks (granites, genisses) as well as Jurassic, Cretaceous and Tertiary (limestones, sandstones) de-posits have been have been identified there. Around one-sixth of Afghanistan's contains Eocene and Quaternary deposits. Quaternary sands and gravels occur in the north, whereas loess covers the Neocene conglomerates, sand-stones and siltstones. Intermingling siltstones, sandstones, conglomerates, sands, gravels and loess are also found southwards of the mountain ranges.

Orogenic processes are still active as evidenced by seismic vibrations taking place in Af-ghanistan's mountains, in particular in the eastern part of the Hindu Kush and its foothills. Kabul lies in a most active seismic zone.

Due to a diversified geological structure Afghanistan is quite rich in mineral resources, which include deposits of uranium, crude oil, gas, iron ore, copper, chromium, zinc and lead, beryl, barite as well as gold, precious and semi-precious stones.

The relief of the high Afghan mountains is youthful; narrow valleys and steep, rugged peaks are there characteristic features; in many places the effect of glaciers is evident. To the west the mountains become lower and their slopes gentler, they often turn into plateaus with the surrounding peaks protruding above them. In a dry climate the steep peaks are well preserved, but the slopes are covered by the weathered rock. The valleys are often closed by alluvial cones, while numerous faults are clearly marked in the relief. Dunes of wandering sands have developed in the sand deserts (National Atlas of DR of Afghanistan)


For centuries Afghanistan has been known for its quality gemstones, particularly lapis lazuli. However in recent years, there have been significant finds of fine emeralds, tourmaline, kun-zite and very recently, rubies.

Emeralds come mainly from the Panjshir valley. Considerably quantities of blue, pink and green tourmaline, as well as significant amounts of kunzite and some aquamarine, have been taken from the pegmatites of the Nuristan region. Smaller quantities of fine ruby have been discovered in the Sarobi area. In addition, there have been small finds of garnet, amethyst, spinel and morganite.

An expert on Afghan Gems, Gary Bowersox, from Honolulu, Hawaii, believes the prospects for future production of emeralds and pegmatite gems, are excellent.

Most of the recently produced gems have come from the north-eastern part of Afghanistan, Badakhshan, Kunar, Laghman, Kabul and Nangahar provinces. In recent years the Hindu Kush and Karakoram range in Pakistan have yeilded spectacular finds of gemstones. These gem bearing regions of Afghanistan and Pakistan "are located in one of the most geologically dynamic regions of the world - at the juncture along which the Indo-Pakistan and Asian crustal plates collided to give rise to the Himalayas. The geology of this region is quite com-plex, and it has been investigated in detail only recently.These investigations indicate that the Hindu Kush area represents the western end of a succession on important gem-producing re-gions that stretch all along the Himalayas through Afghanistan, Pakistan, India, Nepal, and into Burma. " A Status Report on gemstones From Afghanistan. by Gary Bowersox. Gems and Gemology Winter 1985 Due to the insecurity and remote of these sites in Afghanistan most of the gems are smuggled across the border into Pakistan's north-west frontier province.


The soils in the high mountains are desert-steppe or meadow-steppe; in the river valleys the
soils are alluvial or meadow-alluvial: Serozems and brown desert soils cover large portions of the country in the north and south; loess is also found in the north. The deserts are covered by sand and regs.


Afghanistan's vegitation is mostly that typical of semi-deserts and steppes. Ephemerid vegeta-tion grows in the sandy semi-deserts and halophilous vegetation is found in the salt semi-deserts. the most common trees on more humid soils are oaks, ashes, willows, poplars, planes and fruits trees in orcahrds. Forests of the Himalyan type, including evergreen oak woods, grow in the borderland between Afghanistan and pakistan (in Nuristan and Paktia) lying at an altitude up to 2400m above sea level. Pines, spruces and cedars grow at an altitude of 3500m. Alpine meadows extend above that level. The slopes of the Tirbandi Turkistan are covered by pistachio woods.


The fauna of Afghanistan is similar to that of Central Asia and the Mediterranean sub-kingdom of Palaeoarctica. Beast of prey, like the snow leopard, the brown bear, the wolf, the striped hyena, the jackal, the fox live in the mountains. Hoofed mammals are represented by Marco Polo sheep, the goitered gazelle and the ibex. Numerous species of birds, rodents, rep-tiles and amphibians have been recorded. There are also many insects


Afghanistan has mainly a dry, continental climate. The amplitude of temperature between day and night is very large. The great variety of terrain elevation results in different climatic types. Areas, such as north-eastern and central Afghanistan, lying over 2,400 m have long winters (over 6 months). at an altitude of 1300-2400m (eg the zone of Kabul) the climate is temperate or almost temperate, four seasons are clearly marked, and annual precipitation is up to 400mm.
The zone at an altitude between 900 and 1300m is characterized by hot summers and annual precipitation below 200 mm. In areas lying at an altitude below 900 m it is less than 100 mm and the climate is dry and hot. Some small portions in the country's east (Jalalabad, Xost) are influenced by south-eastern monsoons and the climate is subtropical. the highest temperature was recorded in Zaranj (51oC,) the lowest in Sharak (-52.2oC) The higest amount of precipi-tation (1212 mm) was noted on the station Salangi Samali, the lowest was measured in Zaranj (34 mm)

In 1996 when the author was working in Afghanistan, he noticed climate change was having an effect on Afghanistan's weather patterns. Here is a quote from the New York Times:

The arrival of spring each year melts the snow on the vast Hindu Kush mountain range, causing rivers to swell and burst their banks. But this year, the heavy rains have combined to produce the worst flooding for decades.

Afghanistan, torn by 17 years of civil war, has no functioning central Government, with parts of the country controlled by various warring Islamic factions. Deforestation, poor water management and over-grazing are blamed for the ecological problem.

"We are seeing provinces, which were once rich in forests, virtually stripped down to nothing," Mr. McKerrow said. "Grasses and alpine vegetation have been removed because people are either grazing or ploughing right up to the snowline."

"The whole Hindu-Kush is being denuded of forest cover," he added. "The mountains can no longer cope." Global warming, he said, had changed Afghanistan's weather patterns, producing unseasonal rain. In Badakshan, it has rained continuously for three months.

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