Diagenesis and the K-Ar Dating of Shales and Clay Minerals

Perry, Edward A.

doi:10.1130/0016-7606(1974)85<827:datkdo>2.0.co;2

Cited by 65 publications

(28 citation statements)

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“…This mechanism has been supported by structural formulae derived from precise chemical analyses (Foscolos and Kodama, 1974), radiometric argon analyses (Perry, 1974;Aronson and Hower, 1976), experimental thermodynamic and kinetic studies (Eberl and Hower, 1976;Eberl, 1977;Ebefl, 1978), and oxygen isotope investigations (Yeh and Savin, 1977;Eslinger et al, 1979).…”

Section: Copyright 9 1981 the Clay Minerals Societymentioning

confidence: 95%

Burial and Contact Metamorphism in the Mancos Shale

Nadeau

1981

Clays and clay miner.

132

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Abstract--Clay samples from shales and bentonites in the Mancos Shale (Cretaceous) and its stratigraphic equivalents in the southern Rocky Mountain and Colorado Plateau have been analyzed by X-ray powder diffraction methods. The major clay in the shales is mixed layered illite/smectite, with 20-60% illite layers. The regional distribution of ordered vs. random interstratification in the illite/smectite is consistent with the concept of burial metamorphism in which smectite intedayers are converted to illite, resulting finally in ordered interstratification. The interstratification data correlate with other geologic information, including rank of coal and Laramide tectonic activity. In addition, contact metamorphism of the shale by Tertiary igneous intrusions produced a similar clay suite. Chemical variation within these shales (particularly the presence or absence of carbonate) affected the clay conversion reactions in the interbedded bentonites and the shale itself during the early stages of transformation. In extreme cases, shales and bentonites from a single outcrop may contain clays that range from pure smectite (calcareous shales) to ordered illite/smectite containing/>50% illite layers (noncalcareous shales). The use of mixed-layered illite/smectite compositions to infer thermal regimes, therefore, may be misleading unless allowance is made for local chemical controls.

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Section: Copyright 9 1981 the Clay Minerals Societymentioning

confidence: 95%

Burial and Contact Metamorphism in the Mancos Shale

Nadeau

1981

Clays and clay miner.

132

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“…He believes that illite formed in the shallow zone by a process of transfor-mation of I/S minerals, that the same mineral formed in the intermediate zone by a process of neoformation, and in the deep zone by a process of recrystallization in response to Ostwald ripening. We have no doubt about the existence of three plateau ages for the clay minerals of the Gulf Coast sediments, as has been suggested by Perry (1974), recognized by Odin (1982) and reiterated recently by Eberl (1993). But we do not agree with Eberl about his interpretations of three different mechanisms ofillite formation with respect to the three plateau ages.…”

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confidence: 39%

“…This assumption is unjustified if one takes into account the widely different K-Ar dates that were presented by Hurley et al (1963). The Gulf Coast sediments have also been reported to have some prominent stratigraphic breaks or unconformities (Perry 1974), and the Sm-Nd isotopic data of Ohr et al (1991) showed that the provenance for the sediments in the lower sequence is different from that in the upper sequence. The zig-zag pattern in the trend of K in the deep zone may very well reflect variations in the source of the sediments.…”

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confidence: 99%

The Illitization Process in Deeply Buried Shales of the Gulf Coast Area

Clauer

1995

Clays and clay miner.

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“…Perry (1974) examined the K-Ar systematics of clay size fractions from the Gulf Coast shales buried between 1580 and 5525 m. He observed that the proportion of illite layers in I/S of the <0.5 txm fraction increased from 20 to 80% as depth increased. This increase of illite layers was accompanied by decrease in the K-Ar dates from 164 __ 4 to 100 +_ 2 Ma.…”

Section: Introductionmentioning

confidence: 99%

K Transfer during Burial Diagenesis in the Mahakam Delta Basin (Kalimantan, Indonesia)

Furlan

Clauer²,

Chaudhuri

et al. 1996

Clays and clay miner.

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Abstract--Progressively buried sandstones and shales of the Mahakam Delta Basin in Indonesia were studied. Mineralogical, morphological and K-Ar isotopic data were obtained for clay, mica and feldspar minerals. The data indicate that K necessary for the illitization of illite/smectite mixed-layer minerals was supplied mainly from K-feldspar alteration within the sandstones and from mica within the shales. Most of the K-feldspar alteration for both the shale and sandstone samples were observed outside the main zone of illitization, which is restricted to the upper 2000 m of sediment. The feldspar grains were altered below this depth for both lithologies. Therefore, illitization requires an open sedimentary system. This is in contrast to the illitization model for deeply buried shales of the Gulf Coast. That system is commonly assumed to be a closed K system.

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Diagenesis and the K-Ar Dating of Shales and Clay Minerals

Cited by 65 publications

References 0 publications

Burial and Contact Metamorphism in the Mancos Shale

Burial and Contact Metamorphism in the Mancos Shale

The Illitization Process in Deeply Buried Shales of the Gulf Coast Area

K Transfer during Burial Diagenesis in the Mahakam Delta Basin (Kalimantan, Indonesia)

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