 Sand dune in the Egyptian sand sea | ||
| Egyptian sand lake بحر الرمال الأعظم | ||
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The Egyptian sand lake, the Egyptian sand sea or the Great sand lake (English Egyptian Sand Sea, Great Sand Sea, Arabic:بحر الرمال الأعظم, Baḥr ar-Rimāl al-aʿẓam, „large sand lake") Is a sand lake or sand dune field (erg, Arabic:عرق, ʿIrq, „Sea of dunes“, More common in Egyptغرود, Ghurūd, „sand dunes") in the egyptianWestern desert, which is in the northwest of Siwa in Libya begins and until Gilf Kebir Plateau enough. It is around 650 kilometers long, 300 kilometers wide and covers an area of around 72,000 square kilometers - making it larger than the largest German state Bavaria. Some of the sand dunes are over 100 meters high.
background
Sand lakes can be found in various parts of the world, for example in North and South Africa, Asia, Australia and South America. What they all have in common is that they are located in a very narrow strip between the 25th north and 25th south latitude. The largest of its kind is the er-Rubʿ er-Chālī ("Empty quarter") in Saudi Arabia. But there are also several sand lakes in the Sahara: in Morocco the Erg Chebbi, in Algeria the Eastern and the Western Great Erg as in Libya the Calanscio and the Rebiana sand lake.
With a length of 650 kilometers, the Egyptian Sand Sea is one of the largest sand lakes in the world. It originated in the Quaternary.
The Egyptian sand sea was discovered in 1874 by members of the Africa explorer's expedition Gerhard Rohlfs (1831–1896) who actually made their way to Kufra wanted to continue. After the find, however, there was rather disillusionment because the extent of the sand sea was completely unknown:
- „[Karl Alfred von] Zittel had already made a recognition to the west before my arrival and determined that after various high sand chains an unpredictable sea of sand followed in the west. That was a sad prospect. Sand dunes with sand in between, so a Sandocean, that was the only thing that made it impossible for us to advance further. All other obstacles could have been defeated. Mountains could have been climbed, for they cannot be of great height in this part of the Libyan desert, because their existence would have long been proven by climatic phenomena. ... but an uninterrupted sea of sand made everything to shame! "(P. 161 f.)
Since the orientation of the sand dunes was known, the decision was made to follow the expedition in a plain between the dunes Siwa to continue. Several distinctive points of their trip like that Rain field, Sandheim and the Ammonite Hill are still on the maps to this day. On February 20, 1874, after 15 days, the expedition reached Siwa.
On December 29, 1932, the British desert explorer Patrick Clayton (1896–1962) discovered a rock that he called Libyan glass. There is no parallel in the world to this amorphous natural glass.[1]
getting there
Visiting the rock is usually part of a desert excursion to the Gilf Kebir National Park. An all-terrain four-wheel drive vehicle is required to travel through the desert.
You can reach the Egyptian Sand Sea on the drive from Gilf Kebir Plateau to Siwa or el-Baḥrīya.
Tourist Attractions
Sand dunes
Only the southern foothills of the Egyptian Sand Sea are in the Gilf Kebir National Park.
The sand dunes, which are more than 100 kilometers long and sometimes more than 100 meters high, run from northwest to southeast over an area of 650 by 300 kilometers. The dune chains are separated by flat areas one to several kilometers wide.
The width of the plains decreases to the west and north.
Libyan glass territory
The area of the Libyan glass: Silica Glass Field, is part of the Egyptian Sand Sea and is still in the area of the Gilf Kebir National Park. It is located in the south of the Sandsee near to libyan Border. The approximately 50 kilometers long (north-south) and approximately 25 kilometers wide area has its center at 1 25 ° 25 ′ 0 ″ N.25 ° 30 ′ 0 ″ E.
The translucent white, yellowish, light and dark green to black-gray pieces of natural glass can be found on the floor. They are usually several millimeters to one centimeter in size, in exceptional cases even larger than hand. Although they have been smoothed out by wind erosion, some of them also have sharp edges.
These natural glasses have chemical and physical properties that make them unique in the world. With 95-99% they have a high proportion of silicon oxide. The proportions of aluminum oxide (1%) and water (0.1%) are also unusually high. Other included minerals are magnesium, sodium, potassium, calcium, and titanium oxides. Its melting point is unusually high at 1700 ° C, its Mohs hardness is 6 - not quite as hard as quartz. The glass is amorphous; due to the high cooling speed, it could not crystallize out. Inclusions of Cristobalite, SiO4, but also from Baddeleyit, a zirconia ZrO2, indicate a high temperature melt around 1,400 to 1,700 ° C. The glasses were created in the tertiary era.
But now the riddle begins: how was the glass made. To date there is no definite explanation.
Many scientists think that, as in the case of other impactite glasses, a meteorite impact must have been the cause. It should have exploded at a height of around 5,000 meters in order to melt the sand on the ground. The counter-arguments weigh heavily, however: a crater has not yet been found, and there are no other materials that would have to have been formed from such an impact. Even the huge amount of an estimated 1,500 tons cannot be explained. It seems much more likely that SiO was caused by a hydrovolcanic explosion2-Gel reached the surface of the earth. Volcanism is documented in various places in the Western Desert.
Due to its sharp edges, the glass is already used by prehistoric hunters and collectors as a knife or scraper.
It was also used as jewelry. The most famous piece of jewelry from the Pharaonic era, in which Libyan glass was used, is a pectoral about 15 centimeters high, a breast shield, from the tomb of Tutankhamun in the Valley of the Kings, KV 62, that of Howard Carter (1874–1939) was found in a box in the so-called treasury (find number 267d, inv. No. JE 61884). Today you can find it on the upper floor of the Egyptian Museum look at the Tutankhamun Jewels Hall.
In the center there is a scarab, a beetle in the shape of a pill-turner, with spread vulture wings and a vulture's tail. Carter believed the beetle was made of chalcedony. The Italian Vincenzo de Michele was able to prove that it is Libyan glass. The scarab holds a so-called Schen ring, a symbol of eternal duration, as well as a lily or a lotus bouquet in its claws. The bouquets are limited by Uraeus snakeswho should avert disaster. The scarab lifts the celestial barge with its forelegs, on which there is an udjat eye, the eye of the god Horus, two ureae and the lunar disc with the crescent moon. On the moon disc you can see the king in the middle, who is crowned by the ibis-headed moon god Thoth on the left and by the falcon-headed sun god Re-Harachte on the right. Below the scarab there is a colored ribbon and a garland with lotus and papyrus flowers, the symbolic plants of Upper and Lower Egypt.
Rain field
The 2 Rain field(25 ° 10 '49 "N.27 ° 24 ′ 22 ″ E) was a camp site of the Rohlfs expedition of 1874 ed-Dāchla through the Egyptian Sand Sea Siwa on the eastern edge of the Egyptian sand sea. Today only the man-high stone pyramid, which was built at the highest point, bears witness to this today.
Legacies from the Second World War
Of course, the sand sea was a natural barrier in World War II. Nonetheless, there is one in the north 1 Heliport(28 ° 1 '25 "N.25 ° 27 '56 "E.) of the British armed forces from World War II.
activities
The sand lake is ideal for walks in the plains and on the dune ridges. There is some adventure when the vehicles cross the sand dunes.
kitchen
You can have a picnic in various parts of the sand lake. Food and drinks must be brought along. Rubbish must be taken with you and must not be left lying around.
accommodation
Tents must be brought along for the overnight stay.
literature
- Egyptian sand lake
- : Three months in the Libyan desert. Cassel: Fisherman, 1875, Pp. 161-177. Reprint Cologne: Heinrich Barth Institute, 1996, ISBN 978-3-927688-10-0 .
- Libyan glass
- : Composition and origin of desert glasses from the Great Sand Sea of Egypt. In:Journal of the German Society for Geosciences (ZDGG), ISSN1860-1804, Vol.134 (1983), Pp. 521-553, 4 plates.
- : Proceedings / Silica '96: Meeting on Libyan Desert Glass and Related Desert Events, July 18, 1996, Bologna University. Segrate (Milano): Pyramids, 1997.
- : The “Libyan Desert Glass” scarab in Tutankhamen’s pectoral. In:Sahara: preistoria e storia del Sahara, ISSN1120-5679, Vol.10 (1998), Pp. 107-109.
Web links
- The non-impact origin of the Libyan Desert Glass (LDG) by Norbert Bruges.
- Desert glass and the craters of the Eastern Sahara by Reinhart Mazur
