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

Abstract

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.

Mg-rich ferric illite in marine transgressive and highstand systems tracts: Examples from the Paleoproterozoic Semri Group, central India

“…10C) and between K 2 O and CaO (Fig. 10D), in contrast to Jarrar et al (2000) who found good correlation for these oxides. Higher Fe 2 O 3 (total) content distinguishes the CSF peloids from the DFF peloids in the scatter plots (Fig.…”

“…As per AIPEA definition, glauconite is an Fe-rich dioctahedral mica (Jarrar et al, 2000). Mn 2+ is negligible in the minerals and is not represented in the formula.…”

“…10A; [Odin and Matter, 1981], [Ireland et al, 1983], [Velde, 1985], [Dasgupta et al, 1990] and [Jarrar et al, 2000]). Lack of any correlation between K 2 O and Fe 2 O 3 (total) in these phases negates concomitant fixation of interlayer cations during replacement of other cations as described by other workers ( [Valeton et al, 1982] and [Jarrar et al, 2000]) (Fig. 10B), but suggests independent incorporation of interlayer cations during glauconitization.…”

Frequency-Dependent Electrical Characterization of Rock Types from Ewekoro, Eastern Dahomey Basin, Nigeria

“…Gruner 46 reported that glauconite is similar to the layer structures of mica, kaolinites vermiculite or chlorite (clay family). Jarrar et al 47 described its structure as sheet-like, while Odin and Matter 48 , as well as Odin 49 designated it as a dark green pelletal structure. Hence, due to its supposed clay mineral content and structure, the real relative permittivity of glauconite is a little less than that of shale.…”

Rare earth element contents of the Lusi mud: An attempt to identify the environmental origin of the hot mudflow in East Java – Indonesia

“…The Lusi mud is a shale rock type that contains highly SiO 2 , Al 2 O 3 and K 2 O. This type of rocks is usually more enriched in the REE [22,23] compared to arenaceous rock types [24,25]. So, this may be the case that the LREE is found to be abundant within the Lusi mud [26][27][28].…”