Mineralogy, geochemistry and mineralization of the Ririwai complex, northern Nigeria

Kinnaird, Judith A.; Bowden, Peter; Ixer, R. A.; Odling, Nicholas

doi:10.1016/0899-5362(85)90036-3

Cited by 48 publications

(29 citation statements)

References 13 publications

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“…High-temperature K-metasomatism is characterized by an increase in K 2 O, Rb, Zn and a decrease in Na 2 O accompanied by depletion in all REE (Kinnaird et al, 1985). In the studied areas, K-rich rhyolitic volcanics and normal rhyolites have comparable contents of Zn and REE.…”

Section: Mechanisms and Origin Of Potassium Enrichmentmentioning

confidence: 99%

A-type volcanics in Central Eastern Sinai, Egypt

Samuel

Moussa

Azer

2007

Journal of African Earth Sciences

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Section: Mechanisms and Origin Of Potassium Enrichmentmentioning

confidence: 99%

A-type volcanics in Central Eastern Sinai, Egypt

Samuel

Moussa

Azer

2007

Journal of African Earth Sciences

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“…Since these granites have A-type characteristics, they occur generally in an-orogenic environment like in Nigeria (Kinnaird et al, 1985), Namibia (Schmitt et al, 2002), Thor Lake in Canada (Ishihara and Watanabe, 2007) and Baerzhe of the Inner Mongolia (Ishihara and Murakami, 2007), yet they are seen also in orogenic environment like the studied Cape Ashizuri complex and Bokan Mountain complex in Alaska (Philpotts et al, 1994). The Bokan Mountain complex of Jurassic age (151-171 Ma) occurs as intrusive rocks in the early Paleozoic accretionary complex of eugeosynclinal sediments in the southeastern Alaska.…”

Section: Economic Evaluation Of the Ree-rich Granitesmentioning

confidence: 99%

Zircon and REE-rich alkaline plutonic rocks intruded into the accretionary prism at the Cape Ashizuri, Shikoku Island, Japan

Ishihara¹,

Hoshino²

2013

Bull. Geol. Surv. Japan

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Abstract:The Cape Ashizuri body is a small, 12 km 2 , Miocene plutonic complex having gabbroids, syenite, quartz syenite to syenogranite in its southern half and biotite monzogranite in its northern half, right next to the Shimanto accretionary sediments. Chemical analyses indicate that the granitoids have mostly meta-aluminous value of A/CNK<1.0, except for three monzogranite. The granitoids are rich in K 2 O, plotted in the shoshonite-high K fields. The granitoids are also rich in Na 2 O and Rb. Ga content is higher than 18 ppm, indicating characteristics of the A-type granitoids. A distinct characteristic of the Cape Ashizuri granitoids is predominance of HFSE (high-field-strength-element), such as Zr (<1,220 ppm), Hf (25.6 ppm), Nb (<202 ppm), Ta (<14 ppm), LREE (<1002 ppm), HREE (<50.5 ppm), Y (<74 ppm), Th (74.2 ppm). Fluorine is also enriched up to 0.43 wt.%.These HFSE are contained in such common accessory minerals as zircon, ilmenite, allanite and titanite, and rare minerals of fergusonite, chevkinite and others. Zircon is the most common and visible rarely by naked eyes. Zircon in the highest Zr rock, 58A142 sample, contains the maximum values of 2.4 wt.% HfO 2 and 1.0 wt.% Y 2 O 3 . Ilmenite in the 58A142 sample shows 4.3-5.7 wt.% MnO, but that in other quartz syenite shows lower values as 1.7-1.8 wt.% MnO, while its niobium content, up to 3.8 wt.% Nb 2 O 5 , is seen along the rim, indicating the niobium concentrated at the latest magmatic stage. Allanite shows Mn-poor character of the magnetite series (0.44 wt.% MnO), and contains 24.6-25.8 wt.% LREE. The most mafic phase of the gabbroids is 47.0 wt.% SiO 2 and 12.5 wt.% MgO, indicating its origin of the upper mantle. Quartz syenitic rocks have 55-60 wt.% SiO 2 and low Sr 0 ratio of 0.7035, implying a small degree of the partial melting of mafic igneous source rocks in the lower crust for the alkaline rocks. The high contents of HFSE and F were caused by this small degree of the partial melting. The biotite monzogranite in the northern part is considered as a mixed magma generated from the lower igneous crust and overlying accreted sediments of the Shimanto Supergroup. It is interesting to explore hydrothermal REE concentration related to these plutonic and subvolcanic activities.

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“…1971). In alkali granites, Kinnaird et al ( 1985) note tba t arfvedsonite beeomes inereasingly Li-rieh in the albitized zone. Albitization is also often aeeompanied by tbe replaeement of quartz by albite, and/ or by the dissolution of quartz and subsequent infilling ofthe eavities by albite and other hydrothermal minerals.…”

Section: Albite-rieb Zonesmentioning

confidence: 98%

Geologic Characteristics and Genetic Problems Associated with the Development of Granite-Hosted Deposits of Tantalum and Niobium

Pollard

1989

Lanthanides, Tantalum and Niobium

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Granite-hosted deposits of tantalum and niobium form massive or sheetlike zones of disseminated mineralization in the upper portions of some geochemically specialized granite plutons. Such mineralization usually reaches a maximum in association with albite and ftuorite ( ±lithium)-rich zones in small, late-stage intrusions. These zones are formed in some cases by crystallization of ftuorine-rich magmas, and in other cases may result from postmagmatic alteration.The detailed texturaland timing information required to assess the inftuence of magmatic and postmagmatic processes in the development of these deposits is lacking in many cases. Two major genetic models for mineralization envisage metal accumulation to result either from enrichment within the upper portion of a zoned magma chamber at the magmatic stage, or by leaching from lower levels of the granite with precipitation in the upper levels at the postmagmatic stage. Further detailed mineralogical, textural, geochemical and isotopic studies are required before the relative importance of these alternatives can be fully assessed.

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Mineralogy, geochemistry and mineralization of the Ririwai complex, northern Nigeria

Cited by 48 publications

References 13 publications

A-type volcanics in Central Eastern Sinai, Egypt

A-type volcanics in Central Eastern Sinai, Egypt

Zircon and REE-rich alkaline plutonic rocks intruded into the accretionary prism at the Cape Ashizuri, Shikoku Island, Japan

Geologic Characteristics and Genetic Problems Associated with the Development of Granite-Hosted Deposits of Tantalum and Niobium

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