K-Ar dating, X-Ray diffractometry, optical and scanning electron microscopy of glauconies from the early Cretaceous Kurnub Group of Jordan

Amireh, Belal S.; Jarrar, Ghaleb H.; Henjes‐Kunst, Friedhelm; Schneider, Werner

doi:10.1002/(sici)1099-1034(199801/03)33:1<49::aid-gj759>3.0.co;2-y

Cited by 25 publications

(13 citation statements)

References 11 publications

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“…Chemical analysis was performed on the following size fractions: 250-315, 315-400 and 400-500 µm of each sample. These size fractions were used for K-Ar dating (Amireh et al, 1998). The glauconites were separated from quartz, calcite and other foreign minerals using a Frantz-isodynamic magnetic separator at the laboratories of the Institut für Geowissenschaften, TU Braunschweig, Germany.…”

Section: Methodsmentioning

confidence: 99%

“…Occasionally, these crystallites are arranged fibroradially or exhibit the "zebra structure" which probably indicates a calcareous oolitic or a bivalve shell substrate (Amireh et al, 1998). Moreover, relicts of phosphatic grains, biotite flakes and quartz grains have been identified as possible substrate for glauconitization.…”

Section: Petrographymentioning

confidence: 98%

“…1 and 2) and two glauconite-rich beds 80 m below the GMU at A'arda and 130 m above the GMU at Ras En Naqab. Amireh et al (1998). (Amireh et al, 1998).…”

Section: Geologic Settingmentioning

confidence: 99%

“…Amireh et al (1998) conducted K-Ar dating, X-ray diffractometry and petrographic investigation on the glaucony of the early Cretaceous Kurnub Group. Evolved to highly evolved glauconites as defined by Odin and Matter (1981) were used in the investigation.…”

Section: Introductionmentioning

confidence: 99%

“…The constrained age of these glauconies lies at about 96 Ma, which corresponds to the Albian. The evolved to highly evolved nature with K 2 O > 7 wt.% (Odin and Matter, 1981) of the investigated glauconites, their relative persistence throughout Jordan, prompted us to carry out this investigation on the same glauconites dated by Amireh et al (1998).…”

Section: Introductionmentioning

confidence: 99%

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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: Methodsmentioning

confidence: 99%

Section: Petrographymentioning

confidence: 98%

“…1 and 2) and two glauconite-rich beds 80 m below the GMU at A'arda and 130 m above the GMU at Ras En Naqab. Amireh et al (1998). (Amireh et al, 1998).…”

Section: Geologic Settingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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 Occurrence of Glaucony in the Stratigraphic Record: Distribution Patterns and Sequence‐Stratigraphic Significance

Amorosi

2013

Linking Diagenesis to Sequence Stratigraphy

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K–Ar dating of authigenic minerals in siliciclastic sequences: an example from the south Sanfranciscana Basin (Western Minas Gerais, Brazil)

et al. 2014

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K–Ar dating was applied on authigenic potassic minerals which are abundant in sandstones from the south of the Sanfranciscana Basin, Western Minas Gerais State, central Brazil. The Quintinos Member fluvial sandstones (Três Barras Formation, Areado Group) contain significant amounts of authigenic K‐feldspar as microcrystals of adularia and sanidine habits. The ages of these microcrystals cluster into three groups: 106.1 ± 2.2, 89.9 ± 1.9 and 88.8 ± 1.8 Ma (from Albian to Coniacian). The older age of 106.1 ± 2.2 Ma was obtained from the coarse fraction analysed (10–20 µm) that can contain a mixture of detrital potassic minerals (K‐feldspar, muscovite, biotite and illite) and different authigenesis of K‐feldspar (overgrowths and microcrystals). Thus, only the younger ages were interpreted as precipitation of K‐feldspar microcrystals during the Late Cretaceous into the Quintinos Member sandstones. Moreover, these ages can document the formation of microcrystals within a few million years after deposition of the sandstones. The ages of authigenic illite from the Capacete Formation epiclastic sandstones (Mata da Corda Group) range from 88.5 ± 1.9 to 71.5 ± 1.9 Ma (Coniacian–Campanian). These results suggest the timing of the illitization event in these sandstones as well as a synchrony with K‐feldspar authigenesis in the Quintinos Member sandstones. These results are well constrained and are in agreement with stratigraphic, biostratigraphic and radiometric ages previously reported for the Sanfranciscana Basin. Copyright © 2014 John Wiley & Sons, Ltd.

show abstract

K-Ar dating, X-Ray diffractometry, optical and scanning electron microscopy of glauconies from the early Cretaceous Kurnub Group of Jordan

Cited by 25 publications

References 11 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.

The Occurrence of Glaucony in the Stratigraphic Record: Distribution Patterns and Sequence‐Stratigraphic Significance

K–Ar dating of authigenic minerals in siliciclastic sequences: an example from the south Sanfranciscana Basin (Western Minas Gerais, Brazil)

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