Diamond-bearing Kimberlite pipes in the Western Desert of Egypt (Gilf Kebir region)

-- Discovered on a significantly uplifted block of the East-Sahara-Ghost Craton in this region --

A.  Qaret-el.Hanash
B.  Zerzura Plateau

 

A. "Qaret-el-Hanash" structure in the Western Desert (Egypt)
(The first detected Kimberlite pipe nearby the Silica strewnfield)
 
Norbert Brügge, Germany
Dipl.-Geol.

Upload: April 2018
Update:
21.03.2019

           




The Qaret-el-Hanash is a prominent doming structure with a wall on top in the southeast direction of the Libyan Desert Glass area. The hight of the hill is 96 m above ground. The slopes of the elevation are covered with broken sandstones.
During an expedition in 1996 traces of an eroded zone of megascopic sandstone breccia, of about 2-m thickness, have been recognized. The breccia occurs within the wall of Qaret-el-Hanash. Its matrix appears as dull greyish-black material.
Petrographical and mineralogical studies have shown that there are breccias, that consists of local sandstone rock fragments within a matrix of finer quartz grains with glass and several other mineral phases. The results were published in 2004 and declared as evidence of the emergence of Qaret-el- Hanash by an impact.
(Aly Barakat)

However, the most important indication for the emergence of Qaret-el-Hanash, which I postulate now as a
kimberlite pipe, are the photos of Ursula Steiner (Switzerland), which come from the top and southwestern outside slope of the structure and are available to me.
The photos document clear the volcanic origin of Qaret-el-Hanash impressively. The structure is crater-shaped, as it occurs in the Gilf Kebir Crater Field (GKCF), but without (and that is the significant difference) the tilted layers on the edge, indicating an explosion event.



25°04'46"N / 25°56'02"E

 It seems that the most visibly material of the structure is burned sandstone. But some photos from the debris outside (below) also show a strange material of a dark (carbonaceous ?) melt with included many diverse fragments, among ferruginous pieces, debris of basement (BIF), glass, yellow jasper and minerals. The melt contain also large dark brown pieces, which could be diamonds. So far this could not be checked. The whole composition is chaotic.
Important to mention are the intersecting (tectonic) dark lines visible from the air on the southwestern slope of the structure, where the melt with breccias and diamonds were found.


Photos by Ursula Steiner (2012)
The exact coordinates are known to the author. All photos are available in high resolution

  

Top of the Qaret-el-Hanash: Intruded melt with breccias between ferruginous sandstone

Unexplored crater bottom

Breccia

Breccia outside slope

Quartz flow with cracks

Glass

  Diamonds (or Moissanite) ?  

Dark (carbonaceous ?) melt Jasper  



 


Mysterious dark (tectonic?) crosscut lines on the southern slope of the structure


DISCOVERY OF Fe-Cr-Ni SPECKS WITHIN QARET EL-HANASH BRECCIA OF THE LIBYAN GLASS AREA SOUTH WESTERN EGYPT
A. El-Kammar, I. Arafa, K. A. Soliman & A. Barakat --7th International Conference on the Geology of the Arab World, Cairo University, Feb. 2004, P. 1-7


The rock consists of various fragments of local sandstone, i.e., from the area of the glass distribution itself. Fragments of igneous source have never been recorded. The rock fragments range from fraction of mm up to 4-cm in diameter, in the collected specimens. The rock fragments vary in colour from creamy white to brownish-red. They are angular to subrounded and embedded in a dull greyish-black matrix. The microscopic investigation and scanning electron microanalysis confirmed the above-mentioned observation and showed that the matrix consists of shattered and fragmented quartz grains of various sizes. In addition to quartz, the matrix contains many other phases, such as glass, zircon, clay minerals, wollastonite, ilmenite, Mg-ilmenite, rutile and Fe-Cr-Ni specks.

There are several metallic specks of various sizes ranging from 1 micron up to about 10 micron, dispersed in the matrix of Qaret el Hanash breccia. They invade some of the quartz grains. These specks are mainly of irregular outlines and some of them show clear fissures. They are associated with glass and intercalated in some cases with halite. EDAX analyses of such specks indicate that they consist of native Fe, Cr and Ni, in addition to subordinate Si and Ca. Finer particles of similar appearance have also been noticed by the petrographical microscope through the fractures of some of the quartz grains.

The most interesting achievement of the chemical analyses is the detection of high Ir content (2.0-2.2 ppb) within the breccias. This value represents the highest reported values for the area. The reported value of Ir in other breccias in the area is around 1.6-1.9 ppb. The highest reported concentration of Ir by the previous studies was detected from the black streak portions from the Libyan glass itself is 1.25 ppb. (Barakat 2018)
Personal information by Aly Barakat on May 19, 2018: Samples of other phases includes tiny grains of moissanite and diamond.

 

Micro-diamonds
 in Qaret-el-Hanash breccia
Source: E.Diemer (2003)
The analysis of the glassy matrix confirm a similarity to the
 dark LDG variety
Thanks to Aly Barakat
Photomicrograph breccia showing shattered and fragmented quartz grains in the glassy matrix admixed with other phases SEM image and EDS analysis of quartz and glass of worm like structure in the matrix Photomicrograph showing finer particles of the Fe-Cr-Ni phase dispersed within the glassy matrix

 


In Addition:
 

1.) The so-called Siwa-meteorite (not Serra's 36g chondrite) is a breccia-bearing sandstone similar to the Qaret-el-Hanash. The site is located nearby the borehole-spring "Bir Wahed" (29°07'19 " / 25°26'03"), about 15 km southwest of the Siwa Oasis.
 


2.)
Three extraordinary finds of debris in the GSS (dune corridors in the Silica-area) indicate that there are further structures like the Qarat-el-Hanash that are either eroded or covered by dunes.

 

Source: Bogumil Dec, on Youtube, 2016


3.)
Three conspicuous breccias from the
Gilf Kebir Crater Field (GKCF) in the eastern to southeastern direction. On display are numerous clasts of Basement in an iron-containing matrix

      Compare: Ground-Penetrating Radar measurement in the small crater GKCF-28
 

GKCF-01
23°14'37"N / 27°27'37"E

 GKCF-01
 

GKCF-05
23°32'42"N / 27°09'33"E


B. The Mystery of the Kimberlite Breccia on the Zerzura Plateau
(northern of the Egyptian Gilf Kebir)

Norbert Brügge, Germany
Dipl.-Geol.

Upload: May 2018
Update: 21.03.201
9

                         Source: Romano Serra

 

Geological setting: The little explored Zerzura (or Saad) plateau is located north of the Gilf Kebir on the latitude to the Silica strewnfield in the Great Sand Sea in the east. The plateau is divided into two halves by a distinctive wadi. The plateau is to be formed according to the geological map by sandstones of the Upper Cretaceous (Saad Form.). That is not verifiable. It should be Devonian sandstones. After the loss of Ordovician-Silurian strata (erosion), would follow the Archean Basement of the East Sahara Ghost Craton. This scenario is likely because the Zerzura Plateau is placed, like the Gilf Kebir, on the Uweinat-Howar Uplift. Mesozoic layers are generally absent on the Uplift. Layers south of the Zerzura Plateau are probably also not of Cretaceous. The stratification of the sandstones (e.g. in the eastern exit of Wadi Qubba) are similar the fluviatile Paleozoic sandstones in the Gilf Kebir.

       
Sandstone in the eastern exit of Wadi Qubba
 nearby the Silica strewnfield
(Author 2010)

Findings of Lepidosigillaria indicate also Carboniferous layers. Also with regard to the Gilf Kebir Plateau, the geological map is therefore mostly wrong. The entire mapping is based on a misinterpretation of a Carboniferous plant imprint (Paleoweichselia halfa BRÜGGE,2017) from the Aqaba passage and which was erroneously determined as the Mesozoic Weichselia reticulata BRNGT.

 



Zerzura Plateau



Zerzura plateau on air with detected craters Zerzura-1 to 13



Zerzura plateau on geological map (brown)


The Zerzura Plateau has become interesting in recent time because we have to solve another of the many puzzles in the Gilf Kebir region. Romano Serra and his companions in 2011 visited a extraordinary crater, with a peculiar breccia at its center. The author found a photo of it at an Italian PP-presentation. Thankfully, Romano Serra, University of Bologna, has now provided the author with many further photos (below).
In this spectacular breccia from the crater-like structure (crater Zerzura-1) we can see probably a swarm of
micro-diamonds. Unfortunately, apart from the identified location of the find (25°16'46 "/ 25°10'05") there are no further comments or publications.

The visited crater
Zerzura-1 is nearly round and in no case a depression caused by water erosion. There are only two narrow cuts in the wall. The walls of Zerzura-1 crater are flat as after an explosion. In the crater itself is a hole with a plug of breccias therein. On the lower wall of the crater bright layers can be seen, which could be belong to a tuff ring, typical for kimberlite structures. Right: The scenario by me.
The author believes that the breccia in the crater may be a
kimberlite pipe. Many micro-diamonds seem to be present ("white sugar"), but are difficult to recognize in the photos.


  

Crater in the Italian PP-presentation

On air Crater
 
Central Hill Strange hill at the NW-slope Tuff ? Breccia

Breccias

  Thin sections


Now, the author found many further such characteristic craters in the satellite overview. Twelve of them (Zerzura-2 to Zerzura 13) are here located:

 

Zerzura-2

Zerzura-3

Zerzura-4

Zerzura-5

Zerzura-6

Zerzura-7
25°17'47"/ 25°11'37" 25°17'20" / 25°11'50" 25°12'49" / 25°03'32" 25°19'57" / 24°58'39" 25°25'14" / 25°01'42" 25°10'34" / 25°15'40"





Zerzura-8 Zerzura-9 Zerzura-10 Zerzura-11 Zerzura-12 Zerzura-13
25°15'25" / 25°13'20" 25°14'44" / 25°14'16"  25°14'59" / 25°14'56" 25°15'11" / 25°16'08"  25°16'23 / 25°16'06"  25°16'44" / 25°15'43"

In addition of this, there are some pictures from a trekking tour from the year 2003 available, which has thankfully made available to me by Andras Zboray (fjexpeditions.com). In the southern part of the plateau, in a hole in the sandstone, strange hollow cracks can be seen on the wall, on which light mineral deposits stick on the inside. Remarkable are also the round small openings in the floor and in the walls of the hole through which obviously iron-rich solutions have flowed. There is no doubt that hydrovolcanic solutions have ascended here under high pressure and have left their signature.



Location of the hole: 25°07'28"N / 25°19'43"E


 
  



 
Further mysteries
 

1.) Crater-shaped structures with central hill eastern of the northern tip of Gilf Kebir Plateau
(unnamed and unexplored)

In the just found new "Northern Gilf Kebir Crater Field" (N-GKCF) there are craters that are not comparable to the craters in the Gilf Kebir Crater Field (GKCF) in the southeast. A accordance with the craters on the Zerzura Plateau is more obvious.
  


 

2.) The find of pinkish Silica, 50 km southwest of the LDG strewnfield
 

Libyan Desert Glass : New field and Fourier transform infrated data
Francois Fröhlich et al. -- Meteoritics & Planetary Science 48, Nr 12, 2517–2530 (2013)

"Are the Wadi Qubba LDG blocks in situ or were they transported here from the Great Sand Sea by Prehistoric men? Several observations and analyses are consistent with the assignment of this new LDG occurrence to the LDG strewn field.
1. The color (pink) of all the Wadi Qubba specimens is quite different from the Great Sand Sea ones (yellow to green);
2. The molecular structure is clearly slightly different;
3. No large artifacts were found at Wadi Qubba; only one small blade was found that was made from the same glass as the other LDG found in the neighborhood (size, color, molecular structure).
Thus, we infer that the Wadi Qubba LDG blocks are in place and hence they are included in the LDG strewn field."

   
24°52.189' / 25°27.044'

Note: The piece is found in a unnamed Wadi (not Wadi Qubba). It could not have been transported out of the strewnfield to this place. The valley floor is 50m higher. The pinkish color of the piece is extraordinary and was never found in the LDG strewnfield. The quality of the finds does not indicate that they were attractive for humans. Apparently, there is another tectonic structure somewhere outside the known Silica strewnfield.
Of interest in this context are the unknown bright deposits in the valleys. These may correspond with the new craters. Craters 3 and 4 show such bright rocks in the central hill.