An electron microprobe study of glauconites from the continental margin off the west coast of South Africa

Birch, G.F.; Willis, J. P.; Rickard, R. S.

doi:10.1016/0025-3227(76)90065-7

Cited by 37 publications

(13 citation statements)

References 3 publications

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“…Accordingly, the investigated glauconites belong to the 3rd and 4th stage of the maturity scale of Birch et al (1976); or they can be alternatively ranked as evolved to highly evolved (Odin and Matter, 1981). The significant positive relationship between potassium and iron could reflect a genetic relationship between the two cations as has been suggested by Kohler (1980) and discussed above.…”

Section: Major Elementsmentioning

confidence: 88%

The major, trace and rare earth element geochemistry of glauconites from the early Cretaceous Kurnub Group of Jordan.

Jarrar

Amireh

Zachmann³

2000

Geochem. J.

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The major, trace and REE geochemistry of glauconites (as members of the trioctahedral micas) from the early Cretaceous Kurnub Group of Jordan are discussed. The investigated glauconites, with 7.1 to 9.2% K 2 O, are ranked as evolved to highly evolved as defined by Odin and Matter (1981). Al 2 O 3 contents show a significant inverse relationship with K 2 O and Fe 2 O 3 .The trace element contents show a broad range of variation in contrast to the major elements and a consistent relationship with major elements is lacking. The studied glauconites show a very wide range in the total amount of REE (∑REE = 4.5 to 564.5 ppm). Two distinct groups have been differentiated accordingly: I. REE-poor group with ∑REE < 15 ppm and with a weak to moderate LREE/HREE fractionation (1.2 to 8.2); II. REE-rich group with ∑REE up to 565 ppm and with moderately to highly fractionated chondrite-normalized patterns (LREE/HREE ratios 3.5 to 64). The group I glauconites are set in an arenaceous (detrital quartz) dolomitic matrix while group II glauconites are embedded in a mudstone or marlstone or has an argillaceous matrix. The REE abundances are therefore lithologically rather than regionally controlled.When normalized to NASC the investigated glauconites display the distinctive hat-shaped pattern reported for other authigenic minerals of marine origin. The calculated Ce anomaly indicates the formation of glauconites at the boundary between oxic and anoxic environment near the sediment water interface.

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Section: Major Elementsmentioning

confidence: 88%

The major, trace and rare earth element geochemistry of glauconites from the early Cretaceous Kurnub Group of Jordan.

Jarrar

Amireh

Zachmann³

2000

Geochem. J.

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“…This structure suggests that little Mg 2+ or Fe 2+ substitutes for Fe 3+ in the octahedral sites. A transitional character between di-and trioctahedral structures had been noticed by Bischoff (1972) and Hoffert et al (1978) for the hydrothermal clays of the Red Sea and FAMOUS area, respectively, and by Bentor and Kastner (1965) and Birch et al (1976) for the glauconites of various localities. Other peaks corresponding to (020) and (004) d spacing are also generally present except in Samples 506C-3-3, 93-113 cm and 507D-6-2, 103-107 cm, where the (004) peak is missing.…”

Section: Isolated Clay Fractionsmentioning

confidence: 93%

Sedimentology, Mineralogy, and Geochemistry of Green Clay Samples from the Galapagos Hydrothermal Mounds, Holes 506, 506C, and 507D, Deep Sea Drilling Project Leg 70 (Preliminary Data)

Honnorez¹,

Karpoff²,

Trauth-Badaut³

1983

Initial Reports of the Deep Sea Drilling Project

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“…Several workers (e.g., Thompson and Hower, 1975;Birch et al, 1976) suggested that nonstructural Fe in glauconite is in part responsible for the wide variation in glauconite compositions. No evidence has been found in this study to support this suggestion, however, because glauconites which showed evidence of oxidation were excluded from the analyses, it is possible that nonstructural Fe is present in such grains.…”

Section: Interpretation Of the Mrssbauer Spectramentioning

confidence: 99%

“…Because K + and Fe ~+/3+ ions occupy entirely different lattice positions in glauconite and perform different functions, the reactions involving these two cations are probably independent (e.g., Bentor and Kastner, 1965;and Birch et al, 1976), and occur at different times and rates (Foster, 1969), rather than simultaneously as suggested by Hower (1961).…”

Section: Glauconite Genesismentioning

confidence: 99%

A Mössbauer Investigation of Glauconite and its Geological Significance

McConchie

1979

Clays and clay miner.

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Ahstraet--M6ssbauer spectra of 9 glauconite samples from Upper Cretaceous and Lower Tertiary strata in the South Island of New Zealand contain a broad shoulder due to low intensity absorption continuous between 1.0 and 2.5 mm/sec when the absorber is at room temperature; the shoulder is absent, and sharp peaks are apparent in spectra taken with the absorber at 80~ The data suggest that electron transfer occurs between adjacent Fe 3+ and Fe z+ ions at room temperature. The low temperature spectra indicate that all Fe in the glauconites is in octahedral coordination. Fe z+ and Fe z+ ions occur in both cis and trans sites; Fe z+ shows a strong preference for cis sites whereas Fe 2+ shows an even stronger preference for trans sites.The partially variable oxidation state of Fe in glauconite is interpreted in terms of a geochemical model for glauconitization of a degraded or incomplete progenitor phyllosilicate. The model involves exchange of Fe ~+ for other cations which temporarily stabilize the progenitor, followed by FeZ § 3+ charge transfer reactions. Each reaction results from the system's tendency towards equilibrium. The model is supported by the observation that artificially leached glauconite increases both its Fe z+ and its Fe z+ content when placed in a solution containing Fe 2+ as the only Fe ion present.

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An electron microprobe study of glauconites from the continental margin off the west coast of South Africa

Cited by 37 publications

References 3 publications

The major, trace and rare earth element geochemistry of glauconites from the early Cretaceous Kurnub Group of Jordan.

The major, trace and rare earth element geochemistry of glauconites from the early Cretaceous Kurnub Group of Jordan.

Sedimentology, Mineralogy, and Geochemistry of Green Clay Samples from the Galapagos Hydrothermal Mounds, Holes 506, 506C, and 507D, Deep Sea Drilling Project Leg 70 (Preliminary Data)

A Mössbauer Investigation of Glauconite and its Geological Significance

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