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:
Bare Hills, Baltimore Co., Maryland, USA

Oldest recorded age at locality: 510
Youngest recorded age at locality: 470

mindat Locality ID: 3822
mindat URL: http://www.mindat.org/loc-3822.html

Tectonic Settings: Oceanic Arc (Subduction)

Total number of sublocalities beneath "Bare Hills, Baltimore Co., Maryland, USA": 6
Total number of bottom-level sublocalities: 6

Number of Child Localities: 6
Child Localities:
Anthophyllite Location
Bare Hills Copper Mine (Smith Avenue Copper Mine)
Bare Hills Serpentine Quarry East
Discovery Workings (Main Workings)
McMahon Quarry (Greenspring Quarry)
Unnamed Chromite Prospects

Latitude: 39°23'1"N
Longitude: 76°39'52"W
Decimal Degree (lat, lon): 39.383611111111,-76.664444444444

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.

Allophane	Amorphous	Amphibole	Aragonite	Calcite	Chalcanthite	Chalcopyrite	Chlorite	Clay	Clinozoisite
Covellite	Epidote	Feldspar	Garnet	Gypsum	Malachite	Melanterite	Mica	Nickeline	None
Not in a structural group	Pyrite	Pyroxene	Quartz	Rutile	Serpentine	Sphalerite	Spinel	Staurolite	Talc
Titanite	Tourmaline

Actinolite ()*	Albite ()*	Almandine ()*	Anthophyllite ()*	Antigorite ()*
Aragonite ()*	Azurite ()*	Bornite ()*	Calcite ()*	Carrollite ()*
Chalcanthite ()*	Chalcocite ()*	Chalcopyrite ()*	Chromite ()*	Chrysocolla ()*
Chrysotile ()*	Clinochlore ()*	Clinozoisite ()*	Covellite ()*	Cummingtonite ()*
Cuprite ()*	Dolomite ()*	Dravite ()*	Enstatite ()*	Epidote ()*
Ferro-hornblende ()*	Graphite ()*	Gypsum ()*	Hydromagnesite ()*	Laumontite ()*
Magnesite ()*	Magnetite ()*	Malachite ()*	Melanterite ()*	Microcline ()*
Muscovite ()*	Opal ()*	Phlogopite ()*	Pyrite ()*	Pyrrhotite ()*
Quartz ()*	Rutile ()*	Schorl ()*	Sphalerite ()*	Staurolite ()*
Talc ()*	Titanite ()*	Tremolite ()*

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 B C Ca Co Cr Cu Fe H K Mg Na O S Si Ti Zn

Elements from minerals reported directly at this locality: Al Fe H O Si

Structural Groups for minerals in this locality:
Allophane Amorphous Amphibole Aragonite Calcite Chalcanthite Chalcopyrite Chlorite Clay Clinozoisite
Covellite Epidote Feldspar Garnet Gypsum Malachite Melanterite Mica Nickeline None
Not in a structural group Pyrite Pyroxene Quartz Rutile Serpentine Sphalerite Spinel Staurolite Talc
Titanite Tourmaline

48 IMA Minerals at location:

Mineral name	Structural Groups	IMA Formula	Max Age (Ma)	Min Age (Ma)	# of Sublocalities containing mineral	LOCALITY IDs, not mindat ids	# of localities containing mineral
Actinolite ()*	Amphibole	Ca₂(Mg_4.5-2.5Fe²⁺_0.5-2.5)Si₈O₂₂(OH)₂	510	470	2	218401,218403	3419
Albite ()*	Feldspar	Na(AlSi₃O₈)	510	470	1	218401	8803
Almandine ()*	Garnet	Fe²⁺₃Al₂(SiO₄)₃	510	470	1	218401	2353
Anthophyllite ()*	Amphibole	Mg₂Mg₅Si₈O₂₂(OH)₂	510	470	2	218400,218401	718
Antigorite ()*	Serpentine Clay	Mg₃Si₂O₅(OH)₄	510	470	1	218402	708
Aragonite ()*	Aragonite	Ca(CO₃)	510	470	1	218401	3250
Azurite ()*	Not in a structural group	Cu₃(CO₃)₂(OH)₂	510	470	1	218401	5509
Bornite ()*	None	Cu₅FeS₄	510	470	1	218401	5516
Calcite ()*	Calcite	Ca(CO₃)	510	470	2	218401,218404	27770
Carrollite ()*	Spinel	CuCo₂S₄	510	470	1	218401	154
Chalcanthite ()*	Chalcanthite	Cu(SO₄)·5H₂O	510	470	1	218401	925
Chalcocite ()*	None	Cu₂S	510	470	1	218401	5707
Chalcopyrite ()*	Chalcopyrite	CuFeS₂	510	470	2	218401,218404	27198
Chromite ()*	Spinel	Fe²⁺Cr₂O₄	510	470	3	218402,218403,218405	3902
Chrysocolla ()*	Allophane	(Cu_2-xAl_x)H_2-xSi₂O₅(OH)₄·nH₂O	510	470	1	218401	3531
Chrysotile ()*	Serpentine Clay	Mg₃Si₂O₅(OH)₄	510	470	1	218402	951
Clinochlore ()*	Chlorite Clay	Mg₅Al(AlSi₃O₁₀)(OH)₈	510	470	3	218402,218403,218405	1756
Clinozoisite ()*	Clinozoisite Epidote	Ca₂Al₃[Si₂O₇][SiO₄]O(OH)	510	470	1	218404	1025
Covellite ()*	Covellite	CuS	510	470	1	218401	4165
Cummingtonite ()*	Amphibole	Mg₂Mg₅Si₈O₂₂(OH)₂	510	470	1	218401	327
Cuprite ()*	Not in a structural group	Cu₂O	510	470	1	218401	2970
Dolomite ()*	None	CaMg(CO₃)₂	510	470	2	218402,218404	9895
Dravite ()*	Tourmaline	NaMg₃Al₆(Si₆O₁₈)(BO₃)₃(OH)₃(OH)	510	470	1	218404	648
Enstatite ()*	Pyroxene	Mg₂Si₂O₆	510	470	1	218401	944
Epidote ()*	Epidote Clinozoisite	Ca₂(Al₂Fe³⁺)[Si₂O₇][SiO₄]O(OH)	510	470	2	218401,218404	8173
Ferro-hornblende ()*	Amphibole	Ca₂(Fe²⁺₄Al)(Si₇Al)O₂₂(OH)₂	510	470	1	218401	271
Graphite ()*	None	C	510	470	1	218404	2812
Gypsum ()*	Gypsum	Ca(SO₄)·2H₂O	510	470	1	218401	6890
Hydromagnesite ()*	None	Mg₅(CO₃)₄(OH)₂·4H₂O	510	470	1	218403	341
Laumontite ()*	Not in a structural group	CaAl₂Si₄O₁₂·4H₂O	510	470	1	218401	1271
Magnesite ()*	Calcite	Mg(CO₃)	510	470	3	218402,218403,218405	1487
Magnetite ()*	Spinel	Fe²⁺Fe³⁺₂O₄	510	470	4	218400,218401,218402,218405	14899
Malachite ()*	Malachite	Cu₂(CO₃)(OH)₂	510	470	1	218401	12537
Melanterite ()*	Melanterite	Fe(SO₄)·7H₂O	510	470	1	218401	915
Microcline ()*	Feldspar	K(AlSi₃O₈)	510	470	2	218401,218404	4924
Muscovite ()*	Mica Clay	KAl₂(Si₃Al)O₁₀(OH)₂	510	470	1	218404	17380
Opal ()*	Amorphous	SiO₂·nH₂O	510	470	2	218402,218405	2994
Phlogopite ()*	Mica Clay	KMg₃(AlSi₃O₁₀)(OH)₂	510	470	1	218404	2273
Pyrite ()*	Pyrite	FeS₂	510	470	2	218401,218404	39462
Pyrrhotite ()*	Nickeline	Fe₇S₈	510	470	1	218404	9056
Quartz ()*	Quartz	SiO₂	510	470	4	218401,218402,218404,218405	61156
Rutile ()*	Rutile	TiO₂	510	470	1	218404	5614
Schorl ()*	Tourmaline	NaFe²⁺₃Al₆(Si₆O₁₈)(BO₃)₃(OH)₃(OH)	510	470	2	218401,218404	2705
Sphalerite ()*	Sphalerite	ZnS	510	470	1	218404	21482
Staurolite ()*	Staurolite	Fe²⁺₂Al₉Si₄O₂₃(OH)	510	470	0		978
Talc ()*	Clay Talc	Mg₃Si₄O₁₀(OH)₂	510	470	5	218400,218401,218403,218404,218405	3337
Titanite ()*	Titanite	CaTi(SiO₄)O	510	470	1	218404	4899
Tremolite ()*	Amphibole	Ca₂(Mg_5.0-4.5Fe²⁺_0.0-0.5)Si₈O₂₂(OH)₂	510	470	2	218401,218404	2562

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
	podchrome-00496	510	470	Lower Ordovician (490±20 Ma)										Cr	3822	Bare Hills, Baltimore Co., Maryland, USA	Bare Hills	Moiser et al. (2012)		USGSSIR2012_5157

Sample	Source Locality	Reference URL

All locality data graciously provided by mindat.org

All age data...