Omarolluk (original) (raw)
Omarolluks, sometimes shortened to omars, are a distinctive type of glacial erratic that consists of dark siliceous greywacke and exhibits prominent rounded, often deep, hemispherical voids and pits. The hemispherical voids and pits result from the selective dissolution of carbonate concretions within the greywacke. The greywacke is identifiable by its low metamorphic grade and the 10–40% rock fragments, distinctive volcanic clasts, and spherical carbonate concretions that it contains. Omars are typically rounded and range in size from pebbles to boulders. Their rounded shape, whether found in glacial tills or glacial-fluvial (outwash) gravels, indicate that they were eroded from pre-existing littoral or fluvial deposits. Omars are typically found associated with granules and pebbles of oo
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| dbo:abstract | Omarolluks, sometimes shortened to omars, are a distinctive type of glacial erratic that consists of dark siliceous greywacke and exhibits prominent rounded, often deep, hemispherical voids and pits. The hemispherical voids and pits result from the selective dissolution of carbonate concretions within the greywacke. The greywacke is identifiable by its low metamorphic grade and the 10–40% rock fragments, distinctive volcanic clasts, and spherical carbonate concretions that it contains. Omars are typically rounded and range in size from pebbles to boulders. Their rounded shape, whether found in glacial tills or glacial-fluvial (outwash) gravels, indicate that they were eroded from pre-existing littoral or fluvial deposits. Omars are typically found associated with granules and pebbles of oolitic jasper that were transported from the Belcher Islands in Hudson Bay, Canada. The name given these glacial erratics refer to their source, which is the Proterozoic Omarolluk Formation in the Belcher Islands in southeast Hudson Bay. The Laurentide Ice Sheet eroded omars from the Belcher Islands, an archipelago limited to only about a quarter of 1% of Hudson Bay. Glaciers moved omars from the southeastern part of Hudson Bay to central Canada and into the U.S. where they were deposited on moraines. Because scientists know precisely where they came from they are very valuable in documenting the movement of glaciers. (en) |
| dbo:thumbnail | wiki-commons:Special:FilePath/OmarPen.png?width=300 |
| dbo:wikiPageID | 24941985 (xsd:integer) |
| dbo:wikiPageLength | 5627 (xsd:nonNegativeInteger) |
| dbo:wikiPageRevisionID | 895067260 (xsd:integer) |
| dbo:wikiPageWikiLink | dbr:Canada dbr:Proterozoic dbr:Oolite dbr:Belcher_Islands dbr:Archipelago dbr:Hudson_Bay dbr:Cupstone dbr:Glaciers dbr:Moraines dbr:Concretion dbr:File:NutterPen759.pdf dbr:Littoral_zone dbr:Pebble dbr:Adder_stone dbr:Glacial_erratic dbr:Nunavik dbr:Granule_(geology) dbr:Fluvial dbr:Inuktitut dbr:Jasper dbc:Sedimentology dbr:Till dbr:Greywacke dbr:Lithic_technology dbr:Pholad_borings dbr:Itivimiut dbr:R._J._Flaherty dbr:Yup’ik |
| dbp:alt | An Omar with a hemispherical void. Note coin for scale. (en) |
| dbp:boxbgcolor | 604800.0 |
| dbp:caption | An Omar with a hemispherical void in its side. (en) |
| dbp:category | Native Minerals (en) |
| dbp:name | Omar (en) |
| dbp:wikiPageUsesTemplate | dbt:Prehistoric_technology dbt:Infobox_mineral |
| dcterms:subject | dbc:Sedimentology |
| gold:hypernym | dbr:Type |
| rdf:type | owl:Thing dul:ChemicalObject dbo:ChemicalSubstance wikidata:Q7946 dbo:Mineral yago:Abstraction100002137 yago:Material114580897 yago:Matter100020827 yago:Mineral114662574 yago:Part113809207 yago:PhysicalEntity100001930 yago:Relation100031921 yago:Substance100019613 |
| rdfs:comment | Omarolluks, sometimes shortened to omars, are a distinctive type of glacial erratic that consists of dark siliceous greywacke and exhibits prominent rounded, often deep, hemispherical voids and pits. The hemispherical voids and pits result from the selective dissolution of carbonate concretions within the greywacke. The greywacke is identifiable by its low metamorphic grade and the 10–40% rock fragments, distinctive volcanic clasts, and spherical carbonate concretions that it contains. Omars are typically rounded and range in size from pebbles to boulders. Their rounded shape, whether found in glacial tills or glacial-fluvial (outwash) gravels, indicate that they were eroded from pre-existing littoral or fluvial deposits. Omars are typically found associated with granules and pebbles of oo (en) |
| rdfs:label | Omarolluk (en) |
| owl:sameAs | freebase:Omarolluk wikidata:Omarolluk https://global.dbpedia.org/id/4sjrG |
| prov:wasDerivedFrom | wikipedia-en:Omarolluk?oldid=895067260&ns=0 |
| foaf:depiction | wiki-commons:Special:FilePath/OmarPen.png |
| foaf:isPrimaryTopicOf | wikipedia-en:Omarolluk |
| foaf:name | Omar (en) |
| is dbo:wikiPageDisambiguates of | dbr:Omar_(disambiguation) |
| is dbo:wikiPageRedirects of | dbr:Omars |
| is dbo:wikiPageWikiLink of | dbr:Cupstone dbr:Omar_(disambiguation) dbr:Adder_stone dbr:Pholad_borings dbr:Omars |
| is foaf:primaryTopic of | wikipedia-en:Omarolluk |
