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

A	This mineral is Anthropogenic.
G	This mineral is directly dated.
B	This mineral is reported as having this age.
Y	This mineral is using an age reported as an element mineralization period.
O	This mineral is using an age calculated from all data at the locality.
R	The age displayed for this mineral originates from a different, non-child locality.
P	The 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.

Baryte	Chlorite	Clay	Fluorite	Fritzscheite	Mica	None	Rocksalt

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:
Baryte Chlorite Clay Fluorite Fritzscheite Mica None Rocksalt

8 IMA Minerals at location:

Anglesite ()*	Curienite ()*	Donbassite ()*	Francevillite ()*	Galena ()*
Muscovite ()*	Torbernite ()*	Uraninite ()*

Mineral name	Structural Groups	IMA Formula	Max Age (Ma)	Min Age (Ma)	# of localities containing mineral
Anglesite ()*	Baryte	Pb(SO₄)	1840	1720	2734
Curienite ()*	Fritzscheite	Pb(UO₂)₂(VO₄)₂·5H₂O	1840	1720	15
Donbassite ()*	Clay Chlorite	Al₂(Si₃Al)O₁₀(OH)₂·Al_2.33(OH)₆	1840	1720	16
Francevillite ()*	Fritzscheite	Ba(UO₂)₂(VO₄)₂·5H₂O	1840	1720	43
Galena ()*	Rocksalt	PbS	1840	1720	24243
Muscovite ()*	Mica Clay	KAl₂(Si₃Al)O₁₀(OH)₂	1840	1720	17380
Torbernite ()*	None	Cu(UO₂)₂(PO₄)₂·12H₂O	1840	1720	1059
Uraninite ()*	Fluorite	UO₂	1840	1720	2718

Locality Notes from all Ages at Locality:

Age ID	Locality Notes
Giersdorf_00000792	The 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 ID	Max Age (Ma)	Min Age (Ma)	Age as listed in reference	Dating Method	Age Interpret	Prioritized?	Sample Source	Sample Num	Run Num	Age from other Locality	Dated Mineral	Minerals explicitely stated as having this age	Age applies to these Elements	MinDat Locality ID	Dated Locality (Max Age)	Location as listed in reference	Reference	Reference DOI	Reference ID	Age Notes
	Giersdorf_00000792	1840	1720	1780±60	U-Pb	Indirect 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					Yes		Uraninite	U	1749	Oklo Mine, Franceville, Haut-Ogooué Province, Gabon	Oklo Mine	Lancelot et al. (1975)	10.1016/0012-821X(75)90195-8	EPSL25_189	The 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.

Sample	Source Locality	Reference URL

All locality data graciously provided by mindat.org

All age data...