Okaite (Oka Carbonatite Complex, Early Cretaceous, 124-125 Ma; Oka Niobium Mine, Quebec, Canada) : 無料・フリー素材/写真
Okaite (Oka Carbonatite Complex, Early Cretaceous, 124-125 Ma; Oka Niobium Mine, Quebec, Canada) / James St. John
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
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| 説明 | Okaite sample (7.3 centimeters across), a rare intrusive igneous rock, named after the Oka Complex. Okaite is a feldspathoidal ultramafic igneous rock composed of nepheline, melilite, biotite mica, plus minor accessory minerals. This sample is very mildly radioactive.The Oka Carbonatite Complex is located in Quebec, Canada. It’s a large body of alkaline igneous rocks intruded through Precambrian metamorphics. The Oka occurs in the western part of the Canadian Shield’s Monteregian Hills Province. Published research indicates that Oka rocks cooled from magma produced by partial melting of upper mantle rocks (inferred to be metasomatized garnet lherzolites). The rocks in the complex contain some rare elements, including economic concentrations of niobium (Nb). Several mines exploit Oka rocks for their Nb content. Oka rocks include coarsely-crystalline calciocarbonatites (a.k.a. sövites; a.k.a. C1 calciocarbonatites), alnoites, ijolites, and okaites. Age: mid-Barremian Stage, mid-Early Cretaceous, 124-125 million years. Locality: Oka Niobium Mine, southeastern part of the Oka Hills, Oka Hills Inlier, Deux-Montagnes County, just west of Montreal & Laval, far-southern Quebec Province, southeastern Canada. |
| 撮影日 | 2014-08-03 19:39:15 |
| 撮影者 | James St. John |
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