The document summarizes results from a uranium prospection study in the Tin Seririne sedimentary basin in southeast Algeria. Three uranium-bearing horizons were identified: the Precambrian basement-Paleozoic cover interface, the base of the lower Devonian, and the base of the lower Visean. Uranium mineralization shows a relationship with coarse sandstone formations corresponding to lowstand sequences. The Anou Izeleg formation of the lower Devonian represents a priority exploration target due to its fluvio-deltaic sedimentation and secondary uranium minerals. The study contributes to characterizing a regional uranium metallogenic province spanning the Tin Seririne and Tim Mersoi

1. INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)
Technical Meeting on origin of sandstone uranium deposits :
A global perspective
Khaldi A., Nacer JE., Badani A., Mokhtar SA.
Centre de Recherche Nucléaire de Draria – Commissariat à l’Energie Atomique - Algeria
Vienna, Austria, 29 May – 1 June 2012

2. We are pleased to present you today the results of the
uranium prospection in the Tin Seririne basin in the
meridional margin of the Hoggar.
This results are included in a sedimentological fit to try to
elucidate the uraniferous highlighted occurrence
distribution in order to contribute to develop an
exploration program framework in this region.

3.  PRESENTATION OF THE STUDY AREA.
 SOME URANIUM REGIONALE METALLOGENY CONSIDERATIONS OF THE
ALGERIA-NIGER CROSS-BORDER REGION.
 MAIN FEATURES OF URANIUM OCCURRENCES DISCOVERED IN
THE TIN SERIRINE REGION.
 REGIONAL DISTRIBUTION OF THE TIN SERIRINE - TIM MERSOÏ
URANIUM MINERALIZATIONS.
 CONTRIBUTION OF SEQUENCE STRATIGRAPHY TO URANIUM
EXPLORATION - CASE OF THE TIN SERIRINE REGION.
 RESEARCH PERSPECTIVE OF URANIUM OCCURRENCES.
PALEOZOIC AND GONDWANA SEQUENCES SYNTHESIS

4. Geographical situation
of Tin Séririne sedimentary basin
(Tassil Oua N'Ahaggar, Sud-Est du Hoggar)

5. Concerning geology, the Tin Seririne sedimentary basin
belongs to the Oua n’Ahaggar Tassili wich represents the
PALEOZOIC COVER of the southern edge of the central Hoggar.
It is constituting the EXTEND to the north of the TIM MERSOI
sedimentary basin (Niger) known for its uranium potential.

6. Geological context of Tin Séririne sedimentary basin
(Tassil Oua N'Ahaggar, South-East of Hoggar)

7. The regional geological study of this southern part of the
saharian platform has identified three main geological
elements wich have conditionned the geological history of
this cross-border region:
 The Issalane – Aïr mole (uplift block) and his anorogenic
volcanic province (paleozoic);
 The flexure fault of In Azaoua – Arlit;
 The sedimentary area of Tin Séririne – Tim Mersoï basins.

8. 7°
1 2 3 4
5 6 7 8
Tamanrasset
9 10 11 12
13 14 15 16
Bassin
de ISSALANE
Tin Seririne 21° 1. Neogene and Quaternary
2. Tertiary and quaternary volcanism
21°
In Azzaoua 3. Cretaceous
4. Jurassic
5. Trias
6. Carboniferous
7. Devonian
8. Silurian
9. Cambrian-Ordovician
10. Intermediate series (Eocambrian)
In Guezzam
11. Western Hoggar (Pharusian chain)
12. Middle Hoggar (Polycyclic)
13. Easter Hoggar (Tiririne chain)
AÏR 14. Anorogenic volcanism of Aïr
Bassin 15. Faults
de
Tim Mersoï
Agadès
0 100 200 300 400km
7°
Geological scheme of Tin Séririne – Tim Mersoî area

9. For uranium prospection in Tin Séririne region, all
geological and geophysical technics and methods
have been implemented:
 Geological survey.
 Geophysical survey.
 Airborne Geophysical survey.

10. Deposits
Uranium Mineralization
GEOLOGICAL MAP
OF
TIN SERIRINE BASIN

11. Confirmed
radiometric anamoly
TAHAGGART
RADIOMETRIC MAP OF ASSEO AREA
- AEROGEOPHYSICAL SURVEY -

12. SEROUENOUT
TERRANE
MOLE
OF
ISSALANE
7°30’ FAULT
MAGNETIC MAP OF ASSEO AREA
- AEROGEOPHYSICAL SURVEY -

13. In Azzaoua – Arlit Fault
Deforming
the ordovician sandstones

14. W E
Thrust plane
Ordovician
Precambrian basement sandstones
Overthrust of the precambrian basement on the paleozoic cover underlining the
hercynian event in Tin Séririne region

15. URANIUM EXPLORATION RESULTS
IN TIN SERIRINE BASIN
Three uranium mineralized horizons have been
identified :
 Precambrian basement – Paleozoic cover interface;
 Base of lower Devonian ;
 Base of lower Visean.

16. Quaternary
Lower Carboniferous
Middle to upper Devonian
Lower Devonian
Silurian
Cambrian-Ordovician
Precambrian basement
Fault
Basement-Cover interface
Sandstone at the base of the Devonian
Sandstone at the base of the Visean
Tahaggart Deposit
Uranium occurrence
Significant radiometric anomaly
Radiometric anomaly
THE RESULTS
OF THE URANIUM EXPLORATION
IN
TIN SERIRINE BASIN

17. Two types of uraniferous mineralizations are targeted :
 Precambrian basement-paleozoïc cover unconformity
-related mineralization : « Tahaggart type ».
 Continental sandstone-related mineralization of the
base of lower Devonian : « Arlit type ».

18. Ordovician sandstones: The internal Tassili
« Tahaggart region »

19. Ordovician sandstone
Basal conglomerate
Ferrugination
Altered gneiss
THE URANIUM MINERALIZATION IN THE BASEMENT-COVER INTERFACE
- Type Tahaggart -

20. Distribution of uranium mineralization
in the basement-cover interface

21. Distribution of uranium mineralization in the basement-cover interface

22. In the unconformity-related mineralization
type, the regolith shows a significant weathering
of the rock where kaolinization and ferrugination
are dominating.
The mineralization is dominated by phosphatic and
vanadiferous uranium minerals such as:
 Autunite , Yellow mineral.
 Torbernite , Green mineral.
 Carnotite , Yellow mineral.

23. FERRUGINATION
KAOLINIZATION

24. FERRUGINATION

25. MINERALIZED BASAL CONGLOMERATE OF ORDOVICIAN

26. ALTERED AND MINERALIZED RHYOLITE
(REGOLITH)

27. URANIUM MINERALIZATION IN PLACE
(REGOLITH)

28. Sandstones of lower Devonian : External Tassili
« Timouzeline region »

29. Basal sandstone formation of lower Devonian : External Tassili
(I Meskour formation -Timouzeline region)

30. Efei mazerta formation of lower Devonian : External Tassili
(In Azzaoua region)

31. Feldspathic sandstone formation of Timouzeline : External Tassili
(Lower Devonian – Timouzeline region)

32. Feldspathic sandstone formation of Timouzeline : External Tassili
(Lower Devonian – Timouzeline region)

33. The three identified regional horizons bearing uranium
occurrences (Cambrian-Ordovician, lower Devonian and
lower Visean) in the Tin Seririne basin, allowed us to
identify, broadening to the uranium occurrences and
deposits of Tim Mersoï basin :
 The Tamesna cross-border (Tin Séririne-Tim Mersoi)
metallogenic province;
 A metallogic permanence from the Cambo-ordovician
(Tahaggart in Algeria) to the Cretaceous (Azélik in
Niger).

34. Quaternary
Lower Carboniferous
Middle to upper Devonian
Lower Devonian
Silurian
Cambrian-Ordovician
Precambrian basement
Fault
Basement-Cover interface
Lower sandstone whole of Devonian
Lower sandstone whole of Carboniferous
Tahaggart Deposit
Uranium occurrence
Significant radiometric anomaly
Radiometric anomaly
REGIONAL HORIZONS
BEARING URANIUM OCCURRENCES
IN
TIN SERIRINE BASIN

35. 7°
1 2 3 4
5 6 7 8
Tamanrasset 9 10 11 12
13 14 15 16
Bassin
de ISSALANE 21° 1. Neogene and Quaternary
Tin Seririne 2. Tertiary and quaternary volcanism
3. Cretaceous; 4. Jurassic; 5. Trias
21°
In Azzaoua
6. Carboniferous; 7. Devonian; 8. Silurian
9. Cambrian-Ordovician
10. Intermediate series (Eocambrian)
11. Western Hoggar (Pharusian chain)
12. Middle Hoggar (Polycyclic)
13. Easter Hoggar (Tiririne chain)
14. Anorogenic volcanism of Aïr
15. Faults
In Guezzam
16. Uranium deposits and occurrences.
AÏR
Bassin
de
Tim Mersoï
Agadès
0 100 200 300 400km
7°
Uranium Province of Tamesna (Tin Séririne – Tim Mersoi)

36. PALEOZOIC SEQUENCES AND STRATIGRAPHY
We have included all results in a sedimentological
approach to try to elucidate the highlighted
uranium occurrence distribution in this region.

37. LITHOSTRATIGRAPHIC COLUMN
OF
TIN SERIRINE REGION
(OUA N'AHAGGAR Tassili - South-East Hoggar)

38. SEQUENCE ANALYSIS
OF
PALEOZOIQUES SERIES
OF
TIN SERIRINE REGION
(OUA N'AHAGGAR Tassili - South-East Hoggar)

39. Khaldi A.
Plate-forme saharienne (Sud du Hoggar)
Fekirine et Abdallah (1998)
Plate-forme saharienne (Nord du Hoggar)
PALEOZOIC SERIES CORRELATION BETWEEN
NORTHERN AND SOUTHERN MARGINS OF THE SAHARAN PLATFORM

40. EL-HAMET M.O.
Bassin de Tim Mersoi (NIGER)
Khaldi A.
Plate-forme saharienne (Sud du Hoggar)
PALEOZOIC SERIES CORRELATION BETWEEN Fekirine et Abdallah (1998)
TIN SERIRINE (ALGERIA) AND TIM MERSOI (NIGER) BASINS Plate-forme saharienne (Nord du Hoggar)

41. EL-HAMET M.O.
Bassin de Tim Mersoi (NIGER)
Khaldi A.
Plate-forme saharienne (Sud du Hoggar)
Fekirine et Abdallah (1998)
LOCALIZATION OF BEARERS LEVELS OF URANIUM OCCURRENCES Plate-forme saharienne (Nord du Hoggar)
TIN SERIRINE (ALGERIA) AND TIM MERSOI (NIGER) BASINS

42. CONCLUSION, the uranium concentrations encased in Paleozoic
sedimentary series are located systematically in the coarse
sandstone formations corresponding to low-level suite (Lowstand
wedge System Tract.) in close relationship with Ordovician base
unconformity sequences (Tahaggart), Devonian (Tamart-N-Iblis -
Timouzeline) and Carboniferous (Arlit - Arlette - Akouta -
Madaouela). The existence of significant secondary uranium
minerals concentrations, as phosphates and vanadates of
uranium, shows that these deposits have undergone late
remobilization.
The genesis of these mineral concentrations is very tightly
controlled by three main regional factors: Sedimentology (coarse
sandstones) and tectonics (In Azzaoua-Arlit lineament), the redox
phenomena (geochemical zonation) and acid volcanism (Aïr
anorogenic province) presented as the primary source of those
recurring uranium stocks.
These metallogenic considerations at various scales requires an
exhaustive analysis of sedimentological units processions low level
of different sequences to locate fairly objectively uranium
mineralized sandstone bodies.

43. PERSPECTIVE OF URANIUM EXPLORATION
Two types of uranium concentrations are investigated in the Tin
Séririne basin:
 Uranium concentrations related to the precambrian (Upper
Proterorozoic) basement- paleozoic cover unconformity.
 Uraniferous concentrations related to continental sandstone.
Based on these results, the ANOU IZELEG formation of Lower
Devonian (External Tassili), represent a preferential target for
the future exploration program.

44. SEDIMENTOLOGICAL AND METALLOGENIC CHARACTERS
OF ANOU IZELEG FORMATION (LOWER DEVONIAN)
 Fluvio-deltaic formation with channel sedimentation and abundance of
organic matter;
 Secondary uranium mineralization expressed and represented by the
torbernite and autunite;
 Occurence of alkaline volcanic materials in this formation (Efei
Mazerta);
 Formation characterized by a redox front arranged parallel with In
Azaoua-Arlit fault flexure;
 Flexible and local tectonic deformation along the two accidents of In
Azaoua and In Guezzam reflecting the Hercynian event in Tin Séririne
region.
THESE CHARACTERS ARE SIMILAR TO THE GEOLOGICAL ENVIRONMENT
OF ARLIT AND AKOUTA URANIUM DEPOSITS OF TIM MERSOI BASIN IN
NIGER.

45. ANOU IZELEG FORMATION
AREA TARGETED
FOR URANIUM SANDSTONE
EXPLORATION
IN
TIN SERIRINE BASIN
(OUA N'AHAGGAR Tassili - South-East Hoggar)

46. URANIUM OCCURRENCES
OF
TIN SERIRINE BASIN
IN
PALEOZOIC AND GONDWANA SEQUENCES
In order to input these uranium occurrences in a
general framework, a reference to the P. Molina
(1988) PALEOZOIC AND GONDWANA SEQUENCES
SYNTHESIS is proposed.

47. TILLITE
MARINE SEDIMENTS
URANIUM DEPOSITS/OCCURRENCES IN TIM MERSOI BASIN- NIGER
CONTINENTAL – CLASTIC SEDIMENTS
53 – MADAOUELA; 54 – ARLIT; 55 – N’TASSA; 56 – AKOUTA; 57 – EBALA; 58 – IMOURAREN.
BASIC VOLCANICS
UNDATED
ACID VOLCANICS CORRELATION OF URANIUM GEOLOGY
BETWEEN
UNDATED
GRANITES SOUTH AMERICA AND AFRICA
UNDATED
JURASSIC MAP 2
PERMO-TRIASSIC PALEOZOIC AND GONDWANA SEQUENCES
1:10 000 000
In P. MOLINA, 1988.
CARBONIFEROUS
LOWER PALEOZOIC

48. SOUTH AMERICA AFRICA
QUATERNAIRE No Deposit    Calcrètes Namaqoualand
POST-  Marine Phosphates  Marine Phosphates - SENEGAL, ANGOLA (Cabinda),- CONGO
EOCENE
GONDWANA ARGENTINA - BRAZIL  Not-marine Phosphates CENTRAL AFRICAN REPUBLIC (Bakoume)
SEQUENCES
CRETACEOUS  ARGENTINA  NIGER
 JURASSIQUE
JURASSIC
 throught the stratigraphic
column but mostly PERMIAN - NIGER Imouraren  throught the stratigraphic column
GONDWANA
SEQUENCES -ARGENTINA (Sierra Pintada)  CARBONFERE but mostly PERMIAN(SOUTH
AFRICA)
LOWER - NIGER Arlit, Tassa, Akouta, Ebala
- BRAZIL (Figueira)  Madaouela
CARBONIFEROUS
 et  surtout dans le
LOWER PALEOZOIC No known deposits
DEVONIEN
 and  in Brazilian mobile  in Pan-African mobile chains
chains -NAMIBIA post-tectonic Damarian Alaskites (Rossing),
UPPER PROTERZOIC - BRAZIL -CONGO
Metasomatic deposits: Katangian hydrothermal deposits
Itataia ,Lagoa Real,Espinharas  in Central Afric mobile chainse (CAMEROUN, TCHAD)
MIDDLE PROTERZOIC No known deposits  TOGO
LOWER PROTERZOIC
 BRAZIL
Auriferous conglomerates
 GABON (sandstone-type) FRANCEVILLIEN
- Quadrilatero ferriféro  SOUTH AFRICA (Auriferous conglomerates) Witwaterstrand
ARCHEAN No known deposits
 Hightly major deposits  Major deposits (lower than 5000 tU)  Small or Medium deposits (500 - 5000 tU)
 Significant occurrence or very small deposits (lower than 500 tU) .
SPATIAL LOCATION, IN GEOLOGICAL TIME, URANIUM DEPOSITS OF SOUTH AMERICA AND AFRICA
- P. MOLINA, 1988 -

49. 59
60
62
61
TILLITE
MARINE SEDIMENTS
URANIUM DEPOSITS/OCCURRENCES IN TIM MERSOI BASIN- NIGER
CONTINENTAL – CLASTIC SEDIMENTS
53 – MADAOUELA ; 54 – ARLIT ; 55 – N’TASSA ; 56 – AKOUTA ; 57 – EBALA ; 58 – IMOURAREN.
BASIC VOLCANICS
URANIUM DEPOSITS/OCCURRENCES IN TIN SERIRINE BASIN- ALGERIA
UNDATED
ACID VOLCANICS
UNDATED
62 – TAHAGGART ; 60 –TIMOUZELINE ; 61 – TAMART N’IBLIS ; 62 – TAMEDJAOUT.
GRANITES
CORRELATION OF URANIUM GEOLOGY
UNDATED
BETWEEN
SOUTH AMERICA AND AFRICA
JURASSIC
PERMO-TRIASSIC MAP 2
CARBONIFEROUS PALEOZOIC AND GONDWANA SEQUENCES
1:10 000 000
In P. MOLINA, 1988.
LOWER PALEOZOIC

50. SOUTH AMERICA AFRICA
QUATERNAIRE No Deposit    Calcrètes Namaqoualand
POST-  Marine Phosphates  Marine Phosphates - SENEGAL, ANGOLA (Cabinda),- CONGO
EOCENE
GONDWANA ARGENTINA - BRAZIL  Not-marine Phosphates CENTRAL AFRICAN REPUBLIC (Bakoume)
SEQUENCES
CRETACEOUS  ARGENTINA  NIGER
 JURASSIQUE
JURASSIC
 throught the stratigraphic
column but mostly PERMIAN - NIGER Imouraren  throught the stratigraphic column
GONDWANA
SEQUENCES -ARGENTINA (Sierra Pintada)  CARBONFERE but mostly PERMIAN(SOUTH
AFRICA)
LOWER - NIGER Arlit, Tassa, Akouta, Ebala
- BRAZIL (Figueira)  Madaouela
CARBONIFEROUS
 et  surtout dans le ALGERIA  Tahaggart
LOWER PALEOZOIC
DEVONIEN  Timouzeline, Tamarat n'Iblis
 and  in Brazilian mobile  in Pan-African mobile chains
chains -NAMIBIA post-tectonic Damarian Alaskites (Rossing),
UPPER PROTERZOIC - BRAZIL -CONGO
Metasomatic deposits: Katangian hydrothermal deposits
Itataia ,Lagoa Real,Espinharas  in Central Afric mobile chainse (CAMEROUN, TCHAD)
MIDDLE PROTERZOIC No known deposits  TOGO
LOWER PROTERZOIC
 BRAZIL
Auriferous conglomerates
 GABON (sandstone-type) FRANCEVILLIEN
- Quadrilatero ferriféro  SOUTH AFRICA (Auriferous conglomerates) Witwaterstrand
ARCHEAN No known deposits
 Hightly major deposits  Major deposits (lower than 5000 tU)  Small or Medium deposits (500 - 5000 tU)
 Significant occurrence or very small deposits (lower than 500 tU) .
SPATIAL LOCATION, IN GEOLOGICAL TIME, URANIUM DEPOSITS OF SOUTH AMERICA AND AFRICA
REVISED
- P. MOLINA, 1988 -

51. INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)
Technical Meeting on origin of sandstone uranium deposits :
A global perspective