Oolitic Iron Ore

Oolitic iron ore, also known as iron oolite, is a rock composed of small, lenticular, magnetic grains of red iron ore. It often occurs in sandy-calcareous or argillaceous ground masses and is greenish-blue or dark red-brown in color[5External link]. Significant deposits of this rock can be found in the Jurassic formations of England, France, Württemberg and Russia, especially in the Jurassic period[5External link][6External link]. Oolitic iron ore consists of small, round or lenticular grains that often form independent aggregates or are held together by a thin calcareous or argillaceous cohesive mass[6External link]. It is rich in organic remains and has been found in sedimentary formations such as the Silurian in Bohemia, the Devonian in the Eifel, and the Lias and Jura formations[6External link].

Iron oolitic deposits are technically important and occur worldwide. They are particularly widespread in the Brown Jura and are associated with formations such as Aalen and Wasseralfingen in Württemberg, southern Luxembourg, Lorraine, and the English and Russian Brown Jura[6External link]. Some variants of iron oolite contain grains that are not formed from iron hydroxides but from aluminum iron oxide silicate[6External link].

Iron ore in general is a mixture of natural iron compounds and iron-poor or iron-free rocks. The economically important deposits consist mainly of iron oxides or iron carbonates. Iron ore deposits can be formed by magmatic processes, secondary deposits or biogenic processes. The main minerals of iron ore are magnetite, hematite and siderite. Iron ores can be formed in different colored layers known as banding. The oldest source of iron for humans is the swamp iron ore, which is easily mined and reducible. The largest iron ore deposit in the world is located in the Serra dos Carajás region in the Amazon rainforest of Brazil. China, Brazil, Australia and India were the leading countries in iron production in 2009. After extraction, the iron ores are processed to separate the gangue and then crushed, sorted and pelleted. The reduction of iron ores in a blast furnace occurs through a chemical reaction with carbon and carbon monoxide to remove oxygen and produce pig iron, which is further refined into steel[3External link].

Oolitic iron ore, also known as iron oolite, is specific for its composition of small magnetic grains of red iron ore in a sandy, calcareous or clayey matrix. Significant deposits were found in England, France, Württemberg and Russia, especially in the Jurassic period. The iron oolite can come in a variety of colors such as dark maroon or dark red and is often round or lenticular in shape. The grains can form independent aggregates or be held together by a loose calcareous or clayey binding mass. A notable area known for its fossilized iron oolites is the Entre Deux Monts in Switzerland, a small valley[4External link].

In summary, oolitic iron ore, also known as iron oolite, is a rock composed of small, lenticular, magnetic grains of red iron ore. It occurs in sandy-calcareous or argillaceous ground masses and is greenish-blue or dark red-brown in colour. Oolitic iron ore occurs in significant deposits, particularly in the Jurassic formations of various countries. These deposits are rich in organic remains and have technical importance. Iron oolitic deposits are widespread in the Brown Jurassic and associated with different formations in different countries. The iron oolite can also occur in independent aggregates or be held together by a thin calcareous or clayey binder mass.