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:
Harford Co., Maryland, USA

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

mindat Locality ID: 26711
mindat URL: http://www.mindat.org/loc-26711.html

Tectonic Settings:

Total number of sublocalities beneath "Harford Co., Maryland, USA": 54
Total number of bottom-level sublocalities: 48

Number of Child Localities: 29
Child Localities:
Ayres Ore Bank
Benser Ore Bank
Churchville Quarry (Davis Quarry Company Inc.)
Crow Ore Bank
Deer Creek Mine
Flattermash Ore Bank
Gatch Quarry (Gatch Crushed Stone Company Inc.)
Grays Run Quarry (D. M. Stoltzfus And Sons Inc.)
Hanway Ore Bank
Havre De Grace Quarry
Hope Ore Bank
Jarretsville-Dublin District
Joppa Ore Banks
Lomyer Ore Bank
Maryland Green Marble Corporation Quarry (Cardiff Serpentine Quarry)
Phoenix Dome Area
Phoenix Dome Area - B
Pine Grove Farm Ore Banks (Pine Grove Ridge Ore Bank)
Prospect Hill Ore Bank
Scarff Ore Bank
Sewell Ore Bank
Shawsville Area
Shipley Ore Bank
Skillman Ore Banks
Tolley Ore Bank
Walsh Ore Bank
Welzenbach Ore Bank
Willick Ore Bank
Woodensburg-Cardiff District

Latitude: 39°31'12"N
Longitude: 76°21'49"W
Decimal Degree (lat, lon): 39.52,-76.363611111111

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.

Amorphous	Amphibole	Brucite	Calcite	Chalcopyrite	Chlorite	Clay	Clinozoisite	Corundum	Diaspore
Epidote	Natrolite	None	Not in a structural group	Pyrite	Pyroxene	Quartz	Rutile	Serpentine	Smectite-vermiculite
Spinel	Staurolite	Talc	Titanite	Zircon

Actinolite ()*	Ankerite ()*	Anthophyllite ()*	Antigorite ()*	Brucite ()*
Calcite ()*	Chalcopyrite ()*	Chromite ()*	Chrysotile ()*	Clinochlore ()*
Diopside ()*	Dolomite ()*	Enstatite ()*	Epidote ()*	Goethite ()*
Hematite ()*	Ilmenite ()*	Laumontite ()*	Magnesite ()*	Magnetite ()*
Opal ()*	Pyrite ()*	Quartz ()*	Rutile ()*	Scolecite ()*
Staurolite ()*	Talc ()*	Titanite ()*	Tremolite ()*	Vermiculite ()*
Zircon ()*

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 C Ca Cr Cu Fe H Mg O S Si Ti Zr

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

Structural Groups for minerals in this locality:
Amorphous Amphibole Brucite Calcite Chalcopyrite Chlorite Clay Clinozoisite Corundum Diaspore
Epidote Natrolite None Not in a structural group Pyrite Pyroxene Quartz Rutile Serpentine Smectite-vermiculite
Spinel Staurolite Talc Titanite Zircon

31 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			2	218806,218823	3419
Ankerite ()*	None	Ca(Fe²⁺,Mg)(CO₃)₂			2	218794,218826	3092
Anthophyllite ()*	Amphibole	Mg₂Mg₅Si₈O₂₂(OH)₂			2	218795,218828	718
Antigorite ()*	Serpentine Clay	Mg₃Si₂O₅(OH)₄	510	470	5	218791,218797,218803,218806,218823	708
Brucite ()*	Brucite	Mg(OH)₂	510	470	1	218797	462
Calcite ()*	Calcite	Ca(CO₃)			3	218778,218806,218823	27770
Chalcopyrite ()*	Chalcopyrite	CuFeS₂			3	218778,218806,218823	27198
Chromite ()*	Spinel	Fe²⁺Cr₂O₄	510	470	6	218788,218789,218790,218791,218797,218803	3902
Chrysotile ()*	Serpentine Clay	Mg₃Si₂O₅(OH)₄	510	470	2	218797,218823	951
Clinochlore ()*	Chlorite Clay	Mg₅Al(AlSi₃O₁₀)(OH)₈	510	470	4	218788,218797,218801,218803	1756
Diopside ()*	Pyroxene	CaMgSi₂O₆			1	218778	4135
Dolomite ()*	None	CaMg(CO₃)₂			3	218806,218823,218826	9895
Enstatite ()*	Pyroxene	Mg₂Si₂O₆	510	470	0		944
Epidote ()*	Epidote Clinozoisite	Ca₂(Al₂Fe³⁺)[Si₂O₇][SiO₄]O(OH)			2	218778,218785	8173
Goethite ()*	Diaspore	FeO(OH)			1	218786	7437
Hematite ()*	Corundum	Fe₂O₃			1	218786	14640
Ilmenite ()*	Corundum	Fe²⁺Ti⁴⁺O₃			2	218826,218827	5433
Laumontite ()*	Not in a structural group	CaAl₂Si₄O₁₂·4H₂O			2	218778,218785	1271
Magnesite ()*	Calcite	Mg(CO₃)	510	470	5	218795,218797,218801,218806,218823	1487
Magnetite ()*	Spinel	Fe²⁺Fe³⁺₂O₄			8	218780,218792,218794,218801,218813,218823,218826,218827	14899
Opal ()*	Amorphous	SiO₂·nH₂O			2	218806,218823	2994
Pyrite ()*	Pyrite	FeS₂			6	218778,218785,218806,218823,218826,218827	39462
Quartz ()*	Quartz	SiO₂	510	470	6	218785,218786,218794,218797,218806,218823	61156
Rutile ()*	Rutile	TiO₂			2	218826,218827	5614
Scolecite ()*	Natrolite	Ca(Si₃Al₂)O₁₀·3H₂O			1	218778	390
Staurolite ()*	Staurolite	Fe²⁺₂Al₉Si₄O₂₃(OH)	510	470	0		978
Talc ()*	Clay Talc	Mg₃Si₄O₁₀(OH)₂	510	470	9	218794,218795,218797,218798,218801,218806,218823,218826,218827	3337
Titanite ()*	Titanite	CaTi(SiO₄)O			1	218785	4899
Tremolite ()*	Amphibole	Ca₂(Mg_5.0-4.5Fe²⁺_0.0-0.5)Si₈O₂₂(OH)₂			1	218828	2562
Vermiculite ()*	Clay Smectite-vermiculite	Mg_0.7(Mg,Fe,Al)₆(Si,Al)₈O₂₀(OH)₄·8H₂O			2	218794,218795	652
Zircon ()*	Zircon	Zr(SiO₄)			3	218782,218826,218827	5251

3 Ages assigned to this locality:

Excel ID	Max Age (Ma)	Min Age (Ma)	Age as listed in reference	Age applies to these Elements	MinDat Locality ID	Dated Locality (Max Age)	Location as listed in reference	Reference	Reference ID
podchrome-00407	490	490	Lower Ordovician (490±20 Ma)	Cr	142724	Ayres Mine, Jarretsville-Dublin District, Harford Co., Maryland, USA	Ayres	Moiser et al. (2012)	USGSSIR2012_5157
podchrome-00502	510	470	Lower Ordovician (490±20 Ma)	Cr	142771	Cherry Hill Mine, Jarretsville-Dublin District, Harford Co., Maryland, USA	Cherry Hill	Moiser et al. (2012)	USGSSIR2012_5157
podchrome-00497	510	470	Lower Ordovician (490±20 Ma)	Cr	143059	Reed Mine, Jarretsville-Dublin District, Harford Co., Maryland, USA	Reed	Moiser et al. (2012)	USGSSIR2012_5157

Sample	Source Locality	Reference URL
R040063	Harford Co., Maryland, USA	https://rruff.info/R040063

All locality data graciously provided by mindat.org

All age data...