The Negev Highland is basically a sloped plateua stretching from the elevation of 200 metres above sea level and all the way up to Israel’s 3rd highest peak, Ramon mountain peak, at an elevation of 1037 meters.
The area recieves 80-100 mm of rain per year, mainly over a few single days in January and February. The rain falls sporadically and unequally a fact that together with the inferior and partially salty soils creates a panorama made of many distinguished landscapes. Vegetation is mostly in a diffused spot pattern on the slopes and at higher cover in riverbeds, while multicolored formations consist of limestone, dolomite and sandstone can be seen all around.
When rain does fall it may fall very heavily and the poor land’s inability to absorb it will have the water quickly flooding the canyons.
A desert flood, though powerfull and dangerous, can be seen as a miniature replica of the geological and geomorphological long term processes who created the Zin Valley and its surroundings. After the retreat of the great sea and the formation of sedimantary rocks by the deposition and subsequent cementation of shells of the ancient creatures that lived in it, the combined forces of great winds and waters have carved spectacular gorges and cliffs out of the landscape.
Makhtesh Ramon (wrongly translsted Ramon crater though certainly seems like one) is a whole different story. Its 40 kilometers long and 2 to 10 kilometers wide, shaped like an elongated heart, and while being praised as one of the most breathtaking sights you may come across in your lifetime, its also a unique and fascinating geological phenomena.
The Creation of the Makhtesh –
- In the beginning (110 million years ago) – the area where the Ramon Ridge now stands had rivers and lakes, which developed near a shallow sea. Sandstone rocks were deposited onto this continental environment (Lower Cretaceous formation).
- Creation of an ancient sea (90-100 million years ago) – A shallow sea with
a dense population of life forms flooded the area. Skeletons and calcium-rich animal remains were deposited onto the sea bed, on top of the sandstone, forming 500-meter-thick limestone strata. These Cenomanian and Turonian rocks cover the hard rock at the top of the Ramon anticline and other anticlines in Israel.
- Folding (80 million years ago) – In the meantime, the rocks folded and formed
an anticline along the length of the Ramon fault, an ancient underground
geological fault which was “awakened” by movements in the earth’s crust. The area was later flooded by a deeper sea, in which friable limestone rocks formed (Senonian formation). The strata slant at different angles on the two sides of the anticline, forming what is known as an asymmetrical anticline. This is the reason that the later rock does not lie parallel to the older layers. The conglomerate rock found on top of the limestone, at the base of the anticline, was produced under continental conditions, evidence that the peak of the anticline protruded like a continental island above the rest of the anticline which was still under water. Because the top of the anticline was worn away there is no conglomerate rock on the peak.
- Rising (60-70 million years ago) – The Ramon anticline continued to rise along the line of the Ramon fault, with strata of chalk and flint (Senonian formation) and chalk with some clay and phosphates (Maastrichtian formation). Sands and conglomerates that were washed away from the top of the anticline during a constant process of erosion were deposited around the anticline. It is possible that during this period a primary makhtesh was formed to the west.
- Additional marine flooding (40-50 million years ago) – During the Eocene era, the whole area flooded, including the Ramon anticline and the primary makhtesh. The limestone rocks that were deposited in this sea can be seen on the western part of the Ramon anticline and on the Avdat plateau.
- Retreat of the sea and destruction of the anticline peak (30 million years ago) – The sea level dropped and the Ramon anticline continued to rise. The peak of the anticline was largely eroded, exposing a large sandstone core, which had precipitated during the early stages of the formation of the makhtesh. The sea retreated, exposing the region to continental conditions.
- Rivers develop (10-20 million years ago) – Very large rivers, similar in size to the Nile, developed in the region. The currents carried sandstone and pebble aggregates (Neogene formation) here from the area today known as Saudi Arabia. During this period, the opographical height of the region was no more than several dozen meters above the level of the sea.
- Undermining of the range and the creation of Makhtesh Ramon (Makhtesh Ramon today) – The fact that today the heights of the Ramon Ridge stand more than 1,000 meters above sea level is evidence of a marked rise in the ridge. As the ridge rose, it slanted slightly to the northeast (towards the ‘Arava), as the result of the development of the deep valley of the Syrian-African Rift. The great difference in height and the slanting of the ridge led to vigorous erosion and the undermining of the soft sandstone strata, which were carried from the Ramon Ridge to the ‘Arava. The erosion of the inner parts of the ridge created Makhtesh Ramon as it is today.