tholeiitic series
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The tholeiitic series is a classification of subalkaline volcanic igneous rocks characterized by their iron-rich composition. These rocks, primarily basalts, contain plagioclase feldspar, augite, and often pigeonite or hypersthene, with little to no olivine. Tholeiitic basalts typically have a silica content between 45 and 63 percent.12
This series is commonly found along divergent plate boundaries, such as oceanic ridges, and can form extensive plateaus. Examples include the lavas of the Pacific Northwest, the Deccan in India, and the Paran\u00e1 Basin in South America. While often found underwater, tholeiitic lavas also erupt on land, as seen in regions like Iceland.123
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igneous rockClassification of volcanic and hypabyssal rocks…the iron-rich group called the tholeiitic series and the iron-poor group called calc-alkalic. The former group is most commonly found along the oceanic ridges and on the ocean floor; the latter group is characteristic of the volcanic regions of the continental margins (convergent, or destructive, plate boundaries; see below Forms…
Read More…the iron-rich group called the tholeiitic series and the iron-poor group called calc-alkalic. The former group is most commonly found along the oceanic ridges and on the ocean floor; the latter group is characteristic of the volcanic regions of the continental margins (convergent, or destructive, plate boundaries; see below Forms…
Read More- igneous rockConvergent plate boundaries
In Japan a tholeiitic series and a calc-alkalic series sometimes erupt from the same volcano. The former is characterized by lower magnesium, potassium, nickel, chromium, uranium, and thorium and a higher iron:magnesium ratio. Mineralogically, the tholeiitic series characteristically contains pigeonite (a low-calcium monoclinic pyroxene) in the groundmass of…
Read MoreIn Japan a tholeiitic series and a calc-alkalic series sometimes erupt from the same volcano. The former is characterized by lower magnesium, potassium, nickel, chromium, uranium, and thorium and a higher iron:magnesium ratio. Mineralogically, the tholeiitic series characteristically contains pigeonite (a low-calcium monoclinic pyroxene) in the groundmass of…
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