URGENT MESSAGE: We need $75,000 to survive. Click here to find out why.
Log InRegister
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for Educators
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
StatisticsThe ElementsUsersBooks & MagazinesMineral MuseumsMineral Shows & EventsThe Mindat DirectoryDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery

Definition of cap rock

i. Barren vein matter, or a pinch in a vein, supposed to overlie ore.

Synonym of: cap

ii. A hard layer of rock, usually sandstone, a short distance above a coal seam.

iii. A disklike plate over part of or all of the top of most salt domes in the Gulf Coast States and in Germany. It is variably composed of anhydrite, gypsum or limestone, and sometimes some sulphur.


Ref: AGI

iv. A relatively impermeable rock, commonly shale, anhydrite or salt, that forms a barrier or seal above and around an oil- or gas-bearing reservoir rock so that fluids cannot migrate beyond the reservoir. It is often found atop a salt dome. The permeability of a cap rock capable of retaining fluids through geologic time is ~ 10-6-10-8 darcies.

Ref: AGI

v. Eng. The cap rock of the alum shale, Estuarine sandstones on the Yorkshire coast.

Ref: Arkell


Mineral and/or Locality  
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2018, except where stated. Mindat.org relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: June 25, 2018 07:22:25
Go to top of page