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:
Great Western Mine (Laguna Western; Black Bart Mine; Tucker Lease), Great Western-Mirabel Group, Middletown, East Mayacmas District, Mayacmas Mts (Mayacamas Mts), Lake Co., California, USA

Oldest recorded age at locality: 164
Youngest recorded age at locality: 0

mindat Locality ID: 80774
mindat URL: http://www.mindat.org/loc-80774.html

Tectonic Settings: Oceanic Arc (Subduction)

Total number of sublocalities beneath "Great Western Mine (Laguna Western; Black Bart Mine; Tucker Lease), Great Western-Mirabel Group, Middletown, East Mayacmas District, Mayacmas Mts (Mayacamas Mts), Lake Co., California, USA": 0
Total number of bottom-level sublocalities: 0

Latitude: 38°42'48"N
Longitude: 122°38'33"W
Decimal Degree (lat, lon): 38.713333333333,-122.6425

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: C Ca Cr Fe H Hg Mg Ni O Pb S Sb Se Si 

Elements from minerals reported directly at this locality: C Ca Cr Fe H Hg Mg Ni O Pb S Sb Se Si 

Structural Groups for minerals in this locality: 
AmorphousCalciteMilleriteNonePyriteQuartzSphaleriteSpinel

13 IMA Minerals at location:
Calcite  (*)Chromite  (*)Cinnabar  (*)Dolomite  (*)Idrialite  (*)
Jamesonite  (*)Mercury  (*)Metacinnabar  (*)Millerite  (*)Opal  (*)
Pyrite  (*)Quartz  (*)Tiemannite  (*)
Mineral nameStructural GroupsIMA FormulaMax Age (Ma)Min Age (Ma)# of Sublocalities containing mineralLOCALITY IDs, not mindat ids# of localities containing mineral
Calcite  (*)CalciteCa(CO3)164164027770
Chromite  (*)SpinelFe2+Cr2O416416403902
Cinnabar  (*)NoneHgS16416402600
Dolomite  (*)NoneCaMg(CO3)216416409895
Idrialite  (*)NoneC22H14164164015
Jamesonite  (*)NonePb4FeSb6S141641640784
Mercury  (*)NoneHg1641640397
Metacinnabar  (*)SphaleriteHgS1641640255
Millerite  (*)MilleriteNiS16416401066
Opal  (*)AmorphousSiO2·nH2O16416402994
Pyrite  (*)PyriteFeS2164164039462
Quartz  (*)QuartzSiO2164164061156
Tiemannite  (*)SphaleriteHgSe164164083



2 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
Hg-001102.90 ?-?    YesCinnabar, Mercury, Metacinnabar, Schuetteite, TiemanniteHg80795East Mayacmas District, Mayacmas Mts (Mayacamas Mts), Lake Co., California, USA Smith et al. (2008)10.1016/j.epsl.2008.02.029EPSL269_399 
podchrome-00323164164Middle Jurassic (161-168 Ma)       Cr80774Great Western Mine (Laguna Western; Black Bart Mine; Tucker Lease), Great Western-Mirabel Group, Middletown, East Mayacmas District, Mayacmas Mts (Mayacamas Mts), Lake Co., California, USABlack BartMoiser et al. (2012) USGSSIR2012_5157 


SampleSource LocalityReference URL


All locality data graciously provided by mindat.org

All age data...

Other copyright data...