Mineral Evolution Database
Created and maintained by the Mineral Evolution Project in partnership with RRUFF and mindat.
Mineral locality data provided by mindat.org



The Mineral Evolution database is currently under development.

The goal of this page is to present localities at which the mineral is found, and estimates of the oldest possible geologic age of the minerals at these localities.


Locality Name:
Oklobondo Mine (Okélobondo Mine), Franceville, Haut-Ogooué Province, Gabon

Oldest recorded age at locality: 1840
Youngest recorded age at locality: 1720

mindat Locality ID: 17172
mindat URL: http://www.mindat.org/loc-17172.html

Tectonic Settings:

Total number of sublocalities beneath "Oklobondo Mine (Okélobondo Mine), Franceville, Haut-Ogooué Province, Gabon": 0
Total number of bottom-level sublocalities: 0

Latitude: 1°30'30"S
Longitude: 13°16'0"E
Decimal Degree (lat, lon): -1.5083333333333,13.266666666667

AThis mineral is Anthropogenic.
GThis mineral is directly dated.
BThis mineral is reported as having this age.
YThis mineral is using an age reported as an element mineralization period.
OThis mineral is using an age calculated from all data at the locality.
RThe age displayed for this mineral originates from a different, non-child locality.
PThe age displayed for this mineral is the range of ages for this mineral at all of this locality's children.
This mineral's age has not yet been recorded.

This Mineral list contains entries from this locality, including sub-localities. Minerals in bold are reported by mindat.org as occurring directly at this locality, and do not occur at any children (sublocalities) of this locality.

Elements at this locality, including sub-localities: Al Ba Cu H K O P Pb S Si U V 

Elements from minerals reported directly at this locality: Al Ba Cu H K O P Pb S Si U V 

Structural Groups for minerals in this locality: 
BaryteChloriteClayFluoriteFritzscheiteMicaNoneRocksalt

8 IMA Minerals at location:
Anglesite  (*)Curienite  (*)Donbassite  (*)Francevillite  (*)Galena  (*)
Muscovite  (*)Torbernite  (*)Uraninite  (*)
Mineral nameStructural GroupsIMA FormulaMax Age (Ma)Min Age (Ma)# of Sublocalities containing mineralLOCALITY IDs, not mindat ids# of localities containing mineral
Anglesite  (*)BarytePb(SO4)1840172002734
Curienite  (*)FritzscheitePb(UO2)2(VO4)2·5H2O18401720015
Donbassite  (*)Clay ChloriteAl2(Si3Al)O10(OH)2·Al2.33(OH)618401720016
Francevillite  (*)FritzscheiteBa(UO2)2(VO4)2·5H2O18401720043
Galena  (*)RocksaltPbS18401720024243
Muscovite  (*)Mica ClayKAl2(Si3Al)O10(OH)218401720017380
Torbernite  (*)NoneCu(UO2)2(PO4)2·12H2O1840172001059
Uraninite  (*)FluoriteUO21840172002718



Locality Notes from all Ages at Locality:
Age IDLocality Notes
Giersdorf_00000792The Oklo uranium deposit is found in the Franceville sediment. It is host to the only known natural nuclear fission reactor, spread across over a dozen mineral nodes in the shale of the Franceville sediment.


1 Ages assigned to this locality:

Excel IDMax Age (Ma)Min Age (Ma)Age as listed in referenceDating MethodAge InterpretPrioritized?Sample SourceSample NumRun NumAge from other LocalityDated MineralMinerals explicitely stated as having this ageAge applies to these ElementsMinDat Locality IDDated Locality (Max Age)Location as listed in referenceReferenceReference DOIReference IDAge Notes
Giersdorf_00000792184017201780±60U-PbIndirect arguments may, however, put limits on the reactor age: (1) If the age is older than 1.78 b.y., the reactor would have run before the formation of the Franceville series. If this is true, it is almost impossible to explain the fact that the Oklo o   YesUraniniteU1749Oklo Mine, Franceville, Haut-Ogooué Province, GabonOklo MineLancelot et al. (1975)10.1016/0012-821X(75)90195-8EPSL25_189The sampled uranium minerals were drawn from zones outside of the reactor area in the Oklo deposit. Samples with too low a U concentration were additionally discarded. The age was compiled from many samples all intersecting on a concordia diagram, to the left or the right of the concordia line, and is also in agreement with the another author's Rb-Sr age for the Franceville sediment, as well as another's K-Ar age for a tuff in the Franceville deposit.


SampleSource LocalityReference URL


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