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Thomaston Dam railroad cut, Thomaston Dam, Thomaston, Litchfield Co., Connecticut, USAi
Regional Level Types
Thomaston Dam railroad cut- not defined -
Thomaston DamDam
Thomaston- not defined -
Litchfield Co.County
ConnecticutState
USACountry

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Latitude & Longitude (WGS84): 41° 41' 50'' North , 73° 4' 5'' West
Latitude & Longitude (decimal): 41.69750,-73.06806
GeoHash:G#: drkj1qc3w
Köppen climate type:Dfb : Warm-summer humid continental climate
Nearest Settlements:
PlacePopulationDistance
Thomaston1,910 (2017)2.6km
Plymouth12,284 (2017)3.1km
Terryville5,387 (2017)5.2km
Northwest Harwinton3,252 (2017)8.9km
Bristol60,452 (2017)10.3km


With the construction of this dam by the US Army Corps of Engineers following the devastating flood along the Naugatuck River in 1955, the railroad line was moved into a cut along the west side of the dam above the spillway level. At least two workmen died in accidents during the making of this cut (Zodac, 1959). The cut through the Ordovician Ratlum Mountian Schist and some outlier Devonian Nonewaug Granite and pegmatite also exposed numerous hydrothermally mineralized fault zones of unknown origin, but possibly related to Mesozoic rifting. The veins are typically about 0.25 to 1.5 meters thick and contain mostly fluorite, quartz, sulfides (galena, sphalerite, pyrite), calcite and zeolites (stilbite, heulandite, laumontite, harmotome). Other minerals are found in the metamorphic rocks, the pegmatite, or are secondary in origin.

Myer (1962) noted the paragenesis of the hydrothermal minerals in the fault veins as follows:

Hydrothermal mineralization appears to be in four separate stages. Deposition of quartz [and] sphalerite...are the first stage. Quartz cemented the shattered country rock and is the most abundant mineral,...and sphalerite [is] rooted against the quartz. Next, fluorite and calcite, along with galena, [sphalerite], and chalcopyrite, crystallized in a second set of fractures as well as within the quartz-lined cavities. Calcic zeolites, stilbite, heulandite and laumontite, crystallized with calcite in the third stage. They are intergrown and perched on quartz and fluorite druze [sic]. The less siliceous zeolites, [harmotome] and chabazite, are rare and usually found alone on fluorite. The final stage is pyrite in minute crystals that are sprinkled randomly on other minerals.


Collecting is no longer allowed there per US ACOE rules.

There has long been controversy regarding the identification of the brown, generally 6-sided pagoda-like micro-crystals of ZnS found here and generally referred to as wurtzite. This ID was first made by Myer (1962). However, Pete Dunn analyzed crystals via XRD in 1972 (see Yedlin 1973a and b) and obtained "perfect sphalerite patterns". Henderson (1979) showed diagrams of sphalerite crystals "epitaxial" on "wurtzite", and the other way around, with a (0001) (pinacoidal) face of "wurtzite" matching a (111) (tetrahedral) face of sphalerite. Yet (111) is the face that sphalerite twins on. The crystals are actually combined positive and negative tetrahedra of sphalerite twinned on a 6-sided (111) face. Vogt (1991) shows a nice photo of a tetrahedron with a (111) face capping a stack of polysynthetic sphalerite twins resting on multiple sphalerite tetrahedra, but still referring to it as "wurtzite" even though he notes the presence of sphalerite associated with the "wurtzite". Note the re-entrant angles that circumscribe the "prisms" of these pagoda crystals, plus the varying width of the crystals, which are indicative of twinning. Here are some examples of sphalerite tetrahedra with both simple twinning and polysynthetic twinning, some on the same crystal: http://www.mindat.org/photo-783527.html http://www.mindat.org/photo-783535.html and http://www.mindat.org/photo-783519.html The pagoda stacks also cleave along the dodecahedral form {011} and part parallel to the twin plane (111), which is across the "prism" of the stack of twins, whereas wurtzite's best cleavage is prismatic and is not evident here.

A mindat discussion found here http://www.mindat.org/forum.php?read,9,318431,318568#msg-318568 makes an argument that wurtzite is not a separate mineral at all, but merely a sphalerite polytype, while others hold that it is.

Regions containing this locality

North America PlateTectonic Plate

Select Mineral List Type

Standard Detailed Strunz Dana Chemical Elements

Mineral List


60 valid minerals. 6 erroneous literature entries.

Detailed Mineral List:

Actinolite
Formula: ☐{Ca2}{Mg4.5-2.5Fe0.5-2.5}(Si8O22)(OH)2
Albite
Formula: Na(AlSi3O8)
Albite var: Oligoclase
Formula: (Na,Ca)[Al(Si,Al)Si2O8]
Almandine
Formula: Fe2+3Al2(SiO4)3
Anatase
Formula: TiO2
Anglesite ?
Formula: PbSO4
Annite
Formula: KFe2+3(AlSi3O10)(OH)2
'Apophyllite'
Aragonite ?
Formula: CaCO3
Autunite ?
Formula: Ca(UO2)2(PO4)2 · 11H2O
Axinite-(Fe)
Formula: Ca2Fe2+Al2BSi4O15OH
Baryte
Formula: BaSO4
Beryl ?
Formula: Be3Al2(Si6O18)
Brookite
Formula: TiO2
Calcite
Formula: CaCO3
Cerussite
Formula: PbCO3
'Chabazite'
Chalcopyrite
Formula: CuFeS2
'Chlorite Group'
Clinozoisite
Formula: {Ca2}{Al3}(Si2O7)(SiO4)O(OH)
Copiapite
Formula: Fe2+Fe3+4(SO4)6(OH)2 · 20H2O
Datolite
Formula: CaB(SiO4)(OH)
Diopside
Formula: CaMgSi2O6
Epidote
Formula: {Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Fluorapatite
Formula: Ca5(PO4)3F
Fluorite
Formula: CaF2
Galena
Formula: PbS
Goethite
Formula: α-Fe3+O(OH)
Graphite
Formula: C
Greenockite ?
Formula: CdS
Grossular
Formula: Ca3Al2(SiO4)3
Harmotome
Formula: (Ba0.5,Ca0.5,K,Na)5[Al5Si11O32] · 12H2O
Hemimorphite
Formula: Zn4Si2O7(OH)2 · H2O
'Heulandite subgroup'
'Hornblende'
Hydrozincite
Formula: Zn5(CO3)2(OH)6
Ilmenite
Formula: Fe2+TiO3
Jarosite ?
Formula: KFe3+ 3(SO4)2(OH)6
Kaolinite ?
Formula: Al2(Si2O5)(OH)4
Kyanite
Formula: Al2(SiO4)O
Laumontite
Formula: CaAl2Si4O12 · 4H2O
'Limonite'
Formula: (Fe,O,OH,H2O)
Magnetite
Formula: Fe2+Fe3+2O4
Malachite ?
Formula: Cu2(CO3)(OH)2
Melanterite
Formula: Fe2+(H2O)6SO4 · H2O
Microcline
Formula: K(AlSi3O8)
Montmorillonite ?
Formula: (Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O
Mordenite ?
Formula: (Na2,Ca,K2)4(Al8Si40)O96 · 28H2O
Muscovite
Formula: KAl2(AlSi3O10)(OH)2
Muscovite var: Sericite
Formula: KAl2(AlSi3O10)(OH)2
Natrolite
Formula: Na2Al2Si3O10 · 2H2O
Opal
Formula: SiO2 · nH2O
Opal var: Opal-AN
Formula: SiO2 · nH2O
'Phillipsite'
Phlogopite
Formula: KMg3(AlSi3O10)(OH)2
Prehnite
Formula: Ca2Al2Si3O10(OH)2
Pyrite
Formula: FeS2
Pyrolusite ?
Formula: Mn4+O2
Pyromorphite
Formula: Pb5(PO4)3Cl
Pyrrhotite
Formula: Fe7S8
Quartz
Formula: SiO2
Quartz var: Smoky Quartz
Formula: SiO2
Rutile
Formula: TiO2
Schorl
Formula: Na(Fe2+3)Al6(Si6O18)(BO3)3(OH)3(OH)
Sillimanite
Formula: Al2(SiO4)O
Smithsonite ?
Formula: ZnCO3
Sphalerite
Formula: ZnS
Staurolite
Formula: Fe2+2Al9Si4O23(OH)
Stilbite-Ca
Formula: NaCa4[Al9Si27O72] · nH2O
'Stilbite subgroup'
Stilpnomelane ?
Formula: (K,Ca,Na)(Fe2+,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
Sulphur ?
Formula: S8
Titanite
Formula: CaTi(SiO4)O
Vanadinite ?
Formula: Pb5(VO4)3Cl
Wulfenite
Formula: Pb(MoO4)
Wurtzite
Formula: (Zn,Fe)S
Zircon
Formula: Zr(SiO4)

List of minerals arranged by Strunz 10th Edition classification

Group 1 - Elements
Graphite1.CB.05aC
Sulphur ?1.CC.05S8
Group 2 - Sulphides and Sulfosalts
Chalcopyrite2.CB.10aCuFeS2
Galena2.CD.10PbS
Greenockite ?2.CB.45CdS
Pyrite2.EB.05aFeS2
Pyrrhotite2.CC.10Fe7S8
Sphalerite2.CB.05aZnS
Wurtzite ?2.CB.45(Zn,Fe)S
Group 3 - Halides
Fluorite3.AB.25CaF2
Group 4 - Oxides and Hydroxides
Anatase4.DD.05TiO2
Brookite4.DD.10TiO2
Goethite4.00.α-Fe3+O(OH)
Ilmenite4.CB.05Fe2+TiO3
Magnetite4.BB.05Fe2+Fe3+2O4
Opal4.DA.10SiO2 · nH2O
var: Opal-AN4.DA.10SiO2 · nH2O
Pyrolusite ?4.DB.05Mn4+O2
Quartz4.DA.05SiO2
var: Smoky Quartz4.DA.05SiO2
Rutile4.DB.05TiO2
Group 5 - Nitrates and Carbonates
Aragonite ?5.AB.15CaCO3
Calcite5.AB.05CaCO3
Cerussite5.AB.15PbCO3
Hydrozincite5.BA.15Zn5(CO3)2(OH)6
Malachite ?5.BA.10Cu2(CO3)(OH)2
Smithsonite ?5.AB.05ZnCO3
Group 7 - Sulphates, Chromates, Molybdates and Tungstates
Anglesite ?7.AD.35PbSO4
Baryte7.AD.35BaSO4
Copiapite7.DB.35Fe2+Fe3+4(SO4)6(OH)2 · 20H2O
Jarosite ?7.BC.10KFe3+ 3(SO4)2(OH)6
Melanterite7.CB.35Fe2+(H2O)6SO4 · H2O
Wulfenite7.GA.05Pb(MoO4)
Group 8 - Phosphates, Arsenates and Vanadates
Autunite ?8.EB.05Ca(UO2)2(PO4)2 · 11H2O
Fluorapatite8.BN.05Ca5(PO4)3F
Pyromorphite8.BN.05Pb5(PO4)3Cl
Vanadinite ?8.BN.05Pb5(VO4)3Cl
Group 9 - Silicates
Actinolite9.DE.10☐{Ca2}{Mg4.5-2.5Fe0.5-2.5}(Si8O22)(OH)2
Albite9.FA.35Na(AlSi3O8)
var: Oligoclase9.FA.35(Na,Ca)[Al(Si,Al)Si2O8]
Almandine9.AD.25Fe2+3Al2(SiO4)3
Annite9.EC.20KFe2+3(AlSi3O10)(OH)2
Axinite-(Fe)9.BD.20Ca2Fe2+Al2BSi4O15OH
Beryl ?9.CJ.05Be3Al2(Si6O18)
Clinozoisite9.BG.05a{Ca2}{Al3}(Si2O7)(SiO4)O(OH)
Datolite ?9.AJ.20CaB(SiO4)(OH)
Diopside9.DA.15CaMgSi2O6
Epidote9.BG.05a{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Grossular9.AD.25Ca3Al2(SiO4)3
Harmotome9.GC.10(Ba0.5,Ca0.5,K,Na)5[Al5Si11O32] · 12H2O
Hemimorphite9.BD.10Zn4Si2O7(OH)2 · H2O
Kaolinite ?9.ED.05Al2(Si2O5)(OH)4
Kyanite9.AF.15Al2(SiO4)O
Laumontite9.GB.10CaAl2Si4O12 · 4H2O
Microcline9.FA.30K(AlSi3O8)
Montmorillonite ?9.EC.40(Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O
Mordenite ?9.GD.35(Na2,Ca,K2)4(Al8Si40)O96 · 28H2O
Muscovite9.EC.15KAl2(AlSi3O10)(OH)2
var: Sericite9.EC.15KAl2(AlSi3O10)(OH)2
Natrolite ?9.GA.05Na2Al2Si3O10 · 2H2O
Phlogopite ?9.EC.20KMg3(AlSi3O10)(OH)2
Prehnite ?9.DP.20Ca2Al2Si3O10(OH)2
Schorl9.CK.05Na(Fe2+3)Al6(Si6O18)(BO3)3(OH)3(OH)
Sillimanite9.AF.05Al2(SiO4)O
Staurolite9.AF.30Fe2+2Al9Si4O23(OH)
Stilbite-Ca9.GE.10NaCa4[Al9Si27O72] · nH2O
Stilpnomelane ?9.EG.40(K,Ca,Na)(Fe2+,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
Titanite9.AG.15CaTi(SiO4)O
Zircon9.AD.30Zr(SiO4)
Unclassified Minerals, Rocks, etc.
'Apophyllite'-
'Chabazite'-
'Chlorite Group'-
'Heulandite subgroup'-
'Hornblende'-
'Limonite'-(Fe,O,OH,H2O)
'Phillipsite' ?-
'Stilbite subgroup'-

List of minerals arranged by Dana 8th Edition classification

Group 1 - NATIVE ELEMENTS AND ALLOYS
Semi-metals and non-metals
Graphite1.3.6.2C
Sulphur ?1.3.5.1S8
Group 2 - SULFIDES
AmXp, with m:p = 1:1
Galena2.8.1.1PbS
Greenockite ?2.8.7.2CdS
Pyrrhotite2.8.10.1Fe7S8
Sphalerite2.8.2.1ZnS
Wurtzite ?2.8.7.1(Zn,Fe)S
AmBnXp, with (m+n):p = 1:1
Chalcopyrite2.9.1.1CuFeS2
AmBnXp, with (m+n):p = 1:2
Pyrite2.12.1.1FeS2
Group 4 - SIMPLE OXIDES
A2X3
Ilmenite4.3.5.1Fe2+TiO3
AX2
Anatase4.4.4.1TiO2
Brookite4.4.5.1TiO2
Pyrolusite ?4.4.1.4Mn4+O2
Rutile4.4.1.1TiO2
Group 6 - HYDROXIDES AND OXIDES CONTAINING HYDROXYL
XO(OH)
Goethite6.1.1.2α-Fe3+O(OH)
Group 7 - MULTIPLE OXIDES
AB2X4
Magnetite7.2.2.3Fe2+Fe3+2O4
Group 9 - NORMAL HALIDES
AX2
Fluorite9.2.1.1CaF2
Group 14 - ANHYDROUS NORMAL CARBONATES
A(XO3)
Calcite14.1.1.1CaCO3
Cerussite14.1.3.4PbCO3
Smithsonite ?14.1.1.6ZnCO3
Group 16a - ANHYDROUS CARBONATES CONTAINING HYDROXYL OR HALOGEN
Malachite ?16a.3.1.1Cu2(CO3)(OH)2
Hydrozincite16a.4.1.1Zn5(CO3)2(OH)6
Group 28 - ANHYDROUS ACID AND NORMAL SULFATES
AXO4
Anglesite ?28.3.1.3PbSO4
Baryte28.3.1.1BaSO4
Group 29 - HYDRATED ACID AND NORMAL SULFATES
AXO4·xH2O
Melanterite29.6.10.1Fe2+(H2O)6SO4 · H2O
Group 30 - ANHYDROUS SULFATES CONTAINING HYDROXYL OR HALOGEN
(AB)2(XO4)Zq
Jarosite ?30.2.5.1KFe3+ 3(SO4)2(OH)6
Group 31 - HYDRATED SULFATES CONTAINING HYDROXYL OR HALOGEN
Miscellaneous
Copiapite31.10.5.1Fe2+Fe3+4(SO4)6(OH)2 · 20H2O
Group 40 - HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
AB2(XO4)2·xH2O, containing (UO2)2+
Autunite ?40.2a.1.1Ca(UO2)2(PO4)2 · 11H2O
Group 41 - ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
A5(XO4)3Zq
Fluorapatite41.8.1.1Ca5(PO4)3F
Pyromorphite41.8.4.1Pb5(PO4)3Cl
Vanadinite ?41.8.4.3Pb5(VO4)3Cl
Group 48 - ANHYDROUS MOLYBDATES AND TUNGSTATES
AXO4
Wulfenite48.1.3.1Pb(MoO4)
Group 51 - NESOSILICATES Insular SiO4 Groups Only
Insular SiO4 Groups Only with cations in [6] and >[6] coordination
Almandine51.4.3a.2Fe2+3Al2(SiO4)3
Grossular51.4.3b.2Ca3Al2(SiO4)3
Insular SiO4 Groups Only with cations in >[6] coordination
Zircon51.5.2.1Zr(SiO4)
Group 52 - NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
Insular SiO4 Groups and O, OH, F, and H2O with cations in [4] and >[4] coordination
Kyanite52.2.2c.1Al2(SiO4)O
Sillimanite52.2.2a.1Al2(SiO4)O
Staurolite52.2.3.1Fe2+2Al9Si4O23(OH)
Insular SiO4 Groups and O, OH, F, and H2O with cations in [6] and/or >[6] coordination
Titanite52.4.3.1CaTi(SiO4)O
Group 54 - NESOSILICATES Borosilicates and Some Beryllosilicates
Borosilicates and Some Beryllosilicates with B in [4] coordination
Datolite ?54.2.1a.1CaB(SiO4)(OH)
Group 56 - SOROSILICATES Si2O7 Groups, With Additional O, OH, F and H2O
Si2O7 Groups and O, OH, F, and H2O with cations in [4] coordination
Hemimorphite56.1.2.1Zn4Si2O7(OH)2 · H2O
Si2O7 Groups and O, OH, F, and H2O with cations in [4] and/or >[4] coordination
Axinite-(Fe)56.2.2.1Ca2Fe2+Al2BSi4O15OH
Group 58 - SOROSILICATES Insular, Mixed, Single, and Larger Tetrahedral Groups
Insular, Mixed, Single, and Larger Tetrahedral Groups with cations in [6] and higher coordination; single and double groups (n = 1, 2)
Clinozoisite58.2.1a.4{Ca2}{Al3}(Si2O7)(SiO4)O(OH)
Epidote58.2.1a.7{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Group 61 - CYCLOSILICATES Six-Membered Rings
Six-Membered Rings with [Si6O18] rings; possible (OH) and Al substitution
Beryl ?61.1.1.1Be3Al2(Si6O18)
Six-Membered Rings with borate groups
Schorl61.3.1.10Na(Fe2+3)Al6(Si6O18)(BO3)3(OH)3(OH)
Group 65 - INOSILICATES Single-Width,Unbranched Chains,(W=1)
Single-Width Unbranched Chains, W=1 with chains P=2
Diopside65.1.3a.1CaMgSi2O6
Group 71 - PHYLLOSILICATES Sheets of Six-Membered Rings
Sheets of 6-membered rings with 2:1 layers
Annite71.2.2b.3KFe2+3(AlSi3O10)(OH)2
Muscovite71.2.2a.1KAl2(AlSi3O10)(OH)2
Phlogopite ?71.2.2b.1KMg3(AlSi3O10)(OH)2
Sheets of 6-membered rings with 2:1 clays
Montmorillonite ?71.3.1a.2(Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O
Group 72 - PHYLLOSILICATES Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings with 4-membered rings
Prehnite ?72.1.3.1Ca2Al2Si3O10(OH)2
Group 74 - PHYLLOSILICATES Modulated Layers
Modulated Layers with joined islands
Stilpnomelane ?74.1.1.1(K,Ca,Na)(Fe2+,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
Group 75 - TECTOSILICATES Si Tetrahedral Frameworks
Si Tetrahedral Frameworks - SiO2 with [4] coordinated Si
Quartz75.1.3.1SiO2
Si Tetrahedral Frameworks - SiO2 with H2O and organics
Opal75.2.1.1SiO2 · nH2O
Group 76 - TECTOSILICATES Al-Si Framework
Al-Si Framework with Al-Si frameworks
Albite76.1.3.1Na(AlSi3O8)
Microcline76.1.1.5K(AlSi3O8)
Group 77 - TECTOSILICATES Zeolites
Zeolite group - True zeolites
Harmotome77.1.3.5(Ba0.5,Ca0.5,K,Na)5[Al5Si11O32] · 12H2O
Laumontite77.1.1.4CaAl2Si4O12 · 4H2O
Mordenite ?77.1.6.1(Na2,Ca,K2)4(Al8Si40)O96 · 28H2O
Natrolite ?77.1.5.1Na2Al2Si3O10 · 2H2O
Stilbite-Ca77.1.4.3NaCa4[Al9Si27O72] · nH2O
Unclassified Minerals, Mixtures, etc.
Actinolite-☐{Ca2}{Mg4.5-2.5Fe0.5-2.5}(Si8O22)(OH)2
Albite
var: Oligoclase
-(Na,Ca)[Al(Si,Al)Si2O8]
'Apophyllite'-
Aragonite ?-CaCO3
'Chabazite'-
'Chlorite Group'-
'Heulandite subgroup'-
'Hornblende'-
Kaolinite ?-Al2(Si2O5)(OH)4
'Limonite'-(Fe,O,OH,H2O)
Muscovite
var: Sericite
-KAl2(AlSi3O10)(OH)2
Opal
var: Opal-AN
-SiO2 · nH2O
'Phillipsite' ?-
Quartz
var: Smoky Quartz
-SiO2
'Stilbite subgroup'-

List of minerals for each chemical element

HHydrogen
H Harmotome(Ba0.5,Ca0.5,K,Na)5[Al5Si11O32] · 12H2O
H Stilbite-CaNaCa4[Al9Si27O72] · nH2O
H Actinolite☐{Ca2}{Mg4.5-2.5Fe0.5-2.5}(Si8O22)(OH)2
H Clinozoisite{Ca2}{Al3}(Si2O7)(SiO4)O(OH)
H Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
H Opal (var: Opal-AN)SiO2 · nH2O
H LaumontiteCaAl2Si4O12 · 4H2O
H Muscovite (var: Sericite)KAl2(AlSi3O10)(OH)2
H StauroliteFe22+Al9Si4O23(OH)
H Axinite-(Fe)Ca2Fe2+Al2BSi4O15OH
H SchorlNa(Fe32+)Al6(Si6O18)(BO3)3(OH)3(OH)
H OpalSiO2 · nH2O
H CopiapiteFe2+Fe43+(SO4)6(OH)2 · 20H2O
H Goethiteα-Fe3+O(OH)
H Limonite(Fe,O,OH,H2O)
H MelanteriteFe2+(H2O)6SO4 · H2O
H HemimorphiteZn4Si2O7(OH)2 · H2O
H HydrozinciteZn5(CO3)2(OH)6
H AnniteKFe32+(AlSi3O10)(OH)2
H MuscoviteKAl2(AlSi3O10)(OH)2
H AutuniteCa(UO2)2(PO4)2 · 11H2O
H JarositeKFe3+ 3(SO4)2(OH)6
H Mordenite(Na2,Ca,K2)4(Al8Si40)O96 · 28H2O
H Stilpnomelane(K,Ca,Na)(Fe2+,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
H KaoliniteAl2(Si2O5)(OH)4
H Montmorillonite(Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O
H MalachiteCu2(CO3)(OH)2
H DatoliteCaB(SiO4)(OH)
H NatroliteNa2Al2Si3O10 · 2H2O
H PhlogopiteKMg3(AlSi3O10)(OH)2
H PrehniteCa2Al2Si3O10(OH)2
BeBeryllium
Be BerylBe3Al2(Si6O18)
BBoron
B Axinite-(Fe)Ca2Fe2+Al2BSi4O15OH
B SchorlNa(Fe32+)Al6(Si6O18)(BO3)3(OH)3(OH)
B DatoliteCaB(SiO4)(OH)
CCarbon
C CalciteCaCO3
C CerussitePbCO3
C HydrozinciteZn5(CO3)2(OH)6
C GraphiteC
C AragoniteCaCO3
C SmithsoniteZnCO3
C MalachiteCu2(CO3)(OH)2
OOxygen
O Harmotome(Ba0.5,Ca0.5,K,Na)5[Al5Si11O32] · 12H2O
O CalciteCaCO3
O KyaniteAl2(SiO4)O
O PyromorphitePb5(PO4)3Cl
O Stilbite-CaNaCa4[Al9Si27O72] · nH2O
O QuartzSiO2
O Actinolite☐{Ca2}{Mg4.5-2.5Fe0.5-2.5}(Si8O22)(OH)2
O AnataseTiO2
O BaryteBaSO4
O Clinozoisite{Ca2}{Al3}(Si2O7)(SiO4)O(OH)
O Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
O AlmandineFe32+Al2(SiO4)3
O Opal (var: Opal-AN)SiO2 · nH2O
O IlmeniteFe2+TiO3
O LaumontiteCaAl2Si4O12 · 4H2O
O DiopsideCaMgSi2O6
O Muscovite (var: Sericite)KAl2(AlSi3O10)(OH)2
O RutileTiO2
O TitaniteCaTi(SiO4)O
O StauroliteFe22+Al9Si4O23(OH)
O WulfenitePb(MoO4)
O Axinite-(Fe)Ca2Fe2+Al2BSi4O15OH
O BrookiteTiO2
O SchorlNa(Fe32+)Al6(Si6O18)(BO3)3(OH)3(OH)
O Quartz (var: Smoky Quartz)SiO2
O OpalSiO2 · nH2O
O CerussitePbCO3
O CopiapiteFe2+Fe43+(SO4)6(OH)2 · 20H2O
O FluorapatiteCa5(PO4)3F
O GrossularCa3Al2(SiO4)3
O Goethiteα-Fe3+O(OH)
O Limonite(Fe,O,OH,H2O)
O MagnetiteFe2+Fe23+O4
O MelanteriteFe2+(H2O)6SO4 · H2O
O HemimorphiteZn4Si2O7(OH)2 · H2O
O HydrozinciteZn5(CO3)2(OH)6
O ZirconZr(SiO4)
O AlbiteNa(AlSi3O8)
O AnniteKFe32+(AlSi3O10)(OH)2
O MicroclineK(AlSi3O8)
O MuscoviteKAl2(AlSi3O10)(OH)2
O SillimaniteAl2(SiO4)O
O Albite (var: Oligoclase)(Na,Ca)[Al(Si,Al)Si2O8]
O BerylBe3Al2(Si6O18)
O AutuniteCa(UO2)2(PO4)2 · 11H2O
O PyrolusiteMn4+O2
O AragoniteCaCO3
O JarositeKFe3+ 3(SO4)2(OH)6
O Mordenite(Na2,Ca,K2)4(Al8Si40)O96 · 28H2O
O SmithsoniteZnCO3
O Stilpnomelane(K,Ca,Na)(Fe2+,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
O AnglesitePbSO4
O KaoliniteAl2(Si2O5)(OH)4
O Montmorillonite(Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O
O MalachiteCu2(CO3)(OH)2
O VanadinitePb5(VO4)3Cl
O DatoliteCaB(SiO4)(OH)
O NatroliteNa2Al2Si3O10 · 2H2O
O PhlogopiteKMg3(AlSi3O10)(OH)2
O PrehniteCa2Al2Si3O10(OH)2
FFluorine
F FluoriteCaF2
F FluorapatiteCa5(PO4)3F
NaSodium
Na Harmotome(Ba0.5,Ca0.5,K,Na)5[Al5Si11O32] · 12H2O
Na Stilbite-CaNaCa4[Al9Si27O72] · nH2O
Na SchorlNa(Fe32+)Al6(Si6O18)(BO3)3(OH)3(OH)
Na AlbiteNa(AlSi3O8)
Na Albite (var: Oligoclase)(Na,Ca)[Al(Si,Al)Si2O8]
Na Mordenite(Na2,Ca,K2)4(Al8Si40)O96 · 28H2O
Na Stilpnomelane(K,Ca,Na)(Fe2+,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
Na Montmorillonite(Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O
Na NatroliteNa2Al2Si3O10 · 2H2O
MgMagnesium
Mg Actinolite☐{Ca2}{Mg4.5-2.5Fe0.5-2.5}(Si8O22)(OH)2
Mg DiopsideCaMgSi2O6
Mg Stilpnomelane(K,Ca,Na)(Fe2+,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
Mg Montmorillonite(Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O
Mg PhlogopiteKMg3(AlSi3O10)(OH)2
AlAluminium
Al Harmotome(Ba0.5,Ca0.5,K,Na)5[Al5Si11O32] · 12H2O
Al KyaniteAl2(SiO4)O
Al Stilbite-CaNaCa4[Al9Si27O72] · nH2O
Al Clinozoisite{Ca2}{Al3}(Si2O7)(SiO4)O(OH)
Al Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Al AlmandineFe32+Al2(SiO4)3
Al LaumontiteCaAl2Si4O12 · 4H2O
Al Muscovite (var: Sericite)KAl2(AlSi3O10)(OH)2
Al StauroliteFe22+Al9Si4O23(OH)
Al Axinite-(Fe)Ca2Fe2+Al2BSi4O15OH
Al SchorlNa(Fe32+)Al6(Si6O18)(BO3)3(OH)3(OH)
Al GrossularCa3Al2(SiO4)3
Al AlbiteNa(AlSi3O8)
Al AnniteKFe32+(AlSi3O10)(OH)2
Al MicroclineK(AlSi3O8)
Al MuscoviteKAl2(AlSi3O10)(OH)2
Al SillimaniteAl2(SiO4)O
Al Albite (var: Oligoclase)(Na,Ca)[Al(Si,Al)Si2O8]
Al BerylBe3Al2(Si6O18)
Al Mordenite(Na2,Ca,K2)4(Al8Si40)O96 · 28H2O
Al Stilpnomelane(K,Ca,Na)(Fe2+,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
Al KaoliniteAl2(Si2O5)(OH)4
Al Montmorillonite(Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O
Al NatroliteNa2Al2Si3O10 · 2H2O
Al PhlogopiteKMg3(AlSi3O10)(OH)2
Al PrehniteCa2Al2Si3O10(OH)2
SiSilicon
Si Harmotome(Ba0.5,Ca0.5,K,Na)5[Al5Si11O32] · 12H2O
Si KyaniteAl2(SiO4)O
Si Stilbite-CaNaCa4[Al9Si27O72] · nH2O
Si QuartzSiO2
Si Actinolite☐{Ca2}{Mg4.5-2.5Fe0.5-2.5}(Si8O22)(OH)2
Si Clinozoisite{Ca2}{Al3}(Si2O7)(SiO4)O(OH)
Si Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Si AlmandineFe32+Al2(SiO4)3
Si Opal (var: Opal-AN)SiO2 · nH2O
Si LaumontiteCaAl2Si4O12 · 4H2O
Si DiopsideCaMgSi2O6
Si Muscovite (var: Sericite)KAl2(AlSi3O10)(OH)2
Si TitaniteCaTi(SiO4)O
Si StauroliteFe22+Al9Si4O23(OH)
Si Axinite-(Fe)Ca2Fe2+Al2BSi4O15OH
Si SchorlNa(Fe32+)Al6(Si6O18)(BO3)3(OH)3(OH)
Si Quartz (var: Smoky Quartz)SiO2
Si OpalSiO2 · nH2O
Si GrossularCa3Al2(SiO4)3
Si HemimorphiteZn4Si2O7(OH)2 · H2O
Si ZirconZr(SiO4)
Si AlbiteNa(AlSi3O8)
Si AnniteKFe32+(AlSi3O10)(OH)2
Si MicroclineK(AlSi3O8)
Si MuscoviteKAl2(AlSi3O10)(OH)2
Si SillimaniteAl2(SiO4)O
Si Albite (var: Oligoclase)(Na,Ca)[Al(Si,Al)Si2O8]
Si BerylBe3Al2(Si6O18)
Si Mordenite(Na2,Ca,K2)4(Al8Si40)O96 · 28H2O
Si Stilpnomelane(K,Ca,Na)(Fe2+,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
Si KaoliniteAl2(Si2O5)(OH)4
Si Montmorillonite(Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O
Si DatoliteCaB(SiO4)(OH)
Si NatroliteNa2Al2Si3O10 · 2H2O
Si PhlogopiteKMg3(AlSi3O10)(OH)2
Si PrehniteCa2Al2Si3O10(OH)2
PPhosphorus
P PyromorphitePb5(PO4)3Cl
P FluorapatiteCa5(PO4)3F
P AutuniteCa(UO2)2(PO4)2 · 11H2O
SSulfur
S SphaleriteZnS
S GalenaPbS
S PyriteFeS2
S BaryteBaSO4
S ChalcopyriteCuFeS2
S CopiapiteFe2+Fe43+(SO4)6(OH)2 · 20H2O
S MelanteriteFe2+(H2O)6SO4 · H2O
S PyrrhotiteFe7S8
S JarositeKFe3+ 3(SO4)2(OH)6
S SulphurS8
S AnglesitePbSO4
S GreenockiteCdS
S Wurtzite(Zn,Fe)S
ClChlorine
Cl PyromorphitePb5(PO4)3Cl
Cl VanadinitePb5(VO4)3Cl
KPotassium
K Harmotome(Ba0.5,Ca0.5,K,Na)5[Al5Si11O32] · 12H2O
K Muscovite (var: Sericite)KAl2(AlSi3O10)(OH)2
K AnniteKFe32+(AlSi3O10)(OH)2
K MicroclineK(AlSi3O8)
K MuscoviteKAl2(AlSi3O10)(OH)2
K JarositeKFe3+ 3(SO4)2(OH)6
K Mordenite(Na2,Ca,K2)4(Al8Si40)O96 · 28H2O
K Stilpnomelane(K,Ca,Na)(Fe2+,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
K PhlogopiteKMg3(AlSi3O10)(OH)2
CaCalcium
Ca FluoriteCaF2
Ca Harmotome(Ba0.5,Ca0.5,K,Na)5[Al5Si11O32] · 12H2O
Ca CalciteCaCO3
Ca Stilbite-CaNaCa4[Al9Si27O72] · nH2O
Ca Actinolite☐{Ca2}{Mg4.5-2.5Fe0.5-2.5}(Si8O22)(OH)2
Ca Clinozoisite{Ca2}{Al3}(Si2O7)(SiO4)O(OH)
Ca Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Ca LaumontiteCaAl2Si4O12 · 4H2O
Ca DiopsideCaMgSi2O6
Ca TitaniteCaTi(SiO4)O
Ca Axinite-(Fe)Ca2Fe2+Al2BSi4O15OH
Ca FluorapatiteCa5(PO4)3F
Ca GrossularCa3Al2(SiO4)3
Ca Albite (var: Oligoclase)(Na,Ca)[Al(Si,Al)Si2O8]
Ca AutuniteCa(UO2)2(PO4)2 · 11H2O
Ca AragoniteCaCO3
Ca Mordenite(Na2,Ca,K2)4(Al8Si40)O96 · 28H2O
Ca Stilpnomelane(K,Ca,Na)(Fe2+,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
Ca Montmorillonite(Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O
Ca DatoliteCaB(SiO4)(OH)
Ca PrehniteCa2Al2Si3O10(OH)2
TiTitanium
Ti AnataseTiO2
Ti IlmeniteFe2+TiO3
Ti RutileTiO2
Ti TitaniteCaTi(SiO4)O
Ti BrookiteTiO2
VVanadium
V VanadinitePb5(VO4)3Cl
MnManganese
Mn PyrolusiteMn4+O2
FeIron
Fe PyriteFeS2
Fe Actinolite☐{Ca2}{Mg4.5-2.5Fe0.5-2.5}(Si8O22)(OH)2
Fe ChalcopyriteCuFeS2
Fe Epidote{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
Fe AlmandineFe32+Al2(SiO4)3
Fe IlmeniteFe2+TiO3
Fe StauroliteFe22+Al9Si4O23(OH)
Fe Axinite-(Fe)Ca2Fe2+Al2BSi4O15OH
Fe SchorlNa(Fe32+)Al6(Si6O18)(BO3)3(OH)3(OH)
Fe CopiapiteFe2+Fe43+(SO4)6(OH)2 · 20H2O
Fe Goethiteα-Fe3+O(OH)
Fe Limonite(Fe,O,OH,H2O)
Fe MagnetiteFe2+Fe23+O4
Fe MelanteriteFe2+(H2O)6SO4 · H2O
Fe PyrrhotiteFe7S8
Fe AnniteKFe32+(AlSi3O10)(OH)2
Fe JarositeKFe3+ 3(SO4)2(OH)6
Fe Stilpnomelane(K,Ca,Na)(Fe2+,Mg,Al)8(Si,Al)12(O,OH)36 · nH2O
CuCopper
Cu ChalcopyriteCuFeS2
Cu MalachiteCu2(CO3)(OH)2
ZnZinc
Zn SphaleriteZnS
Zn HemimorphiteZn4Si2O7(OH)2 · H2O
Zn HydrozinciteZn5(CO3)2(OH)6
Zn SmithsoniteZnCO3
Zn Wurtzite(Zn,Fe)S
ZrZirconium
Zr ZirconZr(SiO4)
MoMolybdenum
Mo WulfenitePb(MoO4)
CdCadmium
Cd GreenockiteCdS
BaBarium
Ba Harmotome(Ba0.5,Ca0.5,K,Na)5[Al5Si11O32] · 12H2O
Ba BaryteBaSO4
PbLead
Pb GalenaPbS
Pb PyromorphitePb5(PO4)3Cl
Pb WulfenitePb(MoO4)
Pb CerussitePbCO3
Pb AnglesitePbSO4
Pb VanadinitePb5(VO4)3Cl
UUranium
U AutuniteCa(UO2)2(PO4)2 · 11H2O

Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org

Ordovician - Neoproterozoic
443.8 - 1000 Ma



ID: 3190671
Precambrian-Phanerozoic sedimentary rocks

Age: Neoproterozoic to Ordovician (443.8 - 1000 Ma)

Lithology: Mudstone-carbonate-sandstone-conglomerate

Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154]

Early Ordovician
470 - 485.4 Ma



ID: 3020282
Ratlum Mountain Schist

Age: Early Ordovician (470 - 485.4 Ma)

Stratigraphic Name: Ratlum Mountain Schist

Description: Gray, medium-grained, interlayered schist and granofels, composed of quartz, oligoclase, muscovite (in the schist), biotite, and garnet, also staurolite and kyanite in the schist. Numerous layers and lenses of amphibolite; also some of quartz-spessartine (coticule) and calc-silicate rock.

Comments: Part of Central Lowlands; Iapetus (Oceanic) Terrane - Connecticut Valley Synclinorium; Hartland Belt. Equivalents of Savoy Schist of Massachusetts (Emerson, 1898, 1917) (CT009, CT010) and of Moretown Formation of Vermont and Massachusetts (Bedrock Geologic Map of Massachusetts, Zen and others, 1983) (CT011) (includes Golden Hill and Ratlum Mountain Schists) (Lower? Ordovician). Original map source: Connecticut Geological and Natural History Survey, DEP, in cooperation with the U.S. Geological Survey, 2000, Bedrock Geology of Connecticut, shapefile, scale 1:50,000

Lithology: Major:{schist,granofels}, Minor:{amphibolite}, Incidental:{calc silicate rock}

Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. [133]

Data and map coding provided by Macrostrat.org, used under Creative Commons Attribution 4.0 License

References

Sort by

Year (asc) Year (desc) Author (A-Z) Author (Z-A)
Zodac, Peter. (1959), Minerals at Thomaston Dam, Connecticut; Rocks & Minerals: 34: 3.
Schooner, Richard. (1961), The Mineralogy of Connecticut. Fluorescent House, Branford, Connecticut.
Myer, George H. (1962), Hydrothermal Wurtzite at Thomaston Dam, Connecticut. American Mineralogist: 47(7-8): 977-979.
Hiller, John. (1968), Collecting at Thomaston, Conn. Rocks & Minerals: 43(10): 746-747.
Ryerson, Kathleen. (1972), Rock Hound's Guide to Connecticut. Pequot Press: 36-37.
Yedlin, Neal. (1973a), Yedlin on Micromounting. Mineralogical Record: 4(2).
Yedlin, Neal. (1973b), Yedlin on Micromounting. Mineralogical Record: 4(6).
Januzzi, Ronald E. and Seaman, David. (1976), Mineral Localities of Connecticut and Southeastern New York State and Pegmatite Minerals of the World. The Mineralogical Press, Danbury, Connecticut.
Molon, Joseph. (1976), Minerals from Thomaston Dam, Thomaston, Connecticut; Rocks & Minerals: 51: 449.
Henderson, William A. (1979), Microminerals. Thomaston Dam. Mineralogical Record: 10: 239-241.
Shelton, Bill and Webster, Bud. (1979), Mineral Collector's Field Guide: The Northeast. Mineralogy, Wallingford, Connecticut: 46-49.
Segeler, Curt and Molon, Joseph. (1985), The Thomaston Dam Site, Thomaston, Connecticut; Rocks & Minerals: 60(3): 119-124.
Vogt, Wolfgang. (1991), Rediscovering Thomaston Dam. Lapidary Journal: April.
Januzzi, Ronald. E. (1994), Mineral Data Book - Western Connecticut and Environs. Mineralogical Press, Danbury, Connecticut.
Henderson, William A. (1995), Microminerals of Connecticut; Rocks & Minerals: 70(6): 420-425.
Weber, Marcelle H. and Earle C. Sullivan. (1995), Connecticut Mineral Locality Index. Rocks & Minerals (Connecticut Issue): 70(6): 399.


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