Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Clauer, N. Articles by Srodon, J. Search for Related Content GeoRef GeoRef Citation

MODELED SHALE AND SANDSTONE BURIAL DIAGENESIS BASED ON THE K-AR SYSTEMATICS OF ILLITE-TYPE FUNDAMENTAL PARTICLES

Norbert Clauer^1,*, Davy Rousset^1, and Jan rodo²

¹ Centre de Géochimie de la Surface (CNRS-ULP), 1 rue Blessig, 67084 Strasbourg, France
² Institute of Geological Sciences, Polish Academy of Sciences, Senacka 1, 31002 Kraków, Poland

^* E-mail address of corresponding author: nclauer{at}illite.u-strasbg.fr

The clay fraction of the sedimentary succession beneath the Mahakam Delta (eastern Kalimantan, Indonesia) consists mainly of mixed-layer illite-smectite, with minor amounts of kaolinite and/or dickite, discrete detrital illite and chlorite. On the near-shore anticline, evolution of this mixed-layer material is characterized by a decrease in expandability with depth. The mechanism of conversion of smectite to illite layers depends on the lithology of the host rocks: it evolves along a solid-state transformation in the shales and a dissolution-precipitation in the sandstones.

Illite fundamental particles from two sandstones buried at ~4000 m in the Tambora field next to the Handil field on the same near-shore anticline yield a mean K-Ar age of 15.7±1.6 Ma (2), which is younger than the stratigraphic age but still slightly biased by minute amounts of discrete detrital illite. Recalculated after modeling, which takes into account the occurrence of the discrete detrital illite, this K-Ar age becomes 14.4±0.7 Ma. The K-Ar values of the fundamental particles from associated buried shales are significantly older, which can be explained by a mixture of (1) a precursor material similar to that presently deposited in the delta of the Mahakam River, and (2) authigenic fundamental particles incorporating Ar with a ⁴⁰Ar/³⁶Ar ratio above atmospheric value during nucleation and growth on the same detrital precursor.

Application of the modeling to the burial evolution of <0.4 µm particles from both the shales and the sandstones of the basin points to a contribution of detrital micaceous material in both lithologies, (1) in the sandstones as a detrital component dissolving progressively and mixed mechanically with the authigenic fundamental particles, and (2) in the shales as a detrital precursor progressively releasing radiogenic ⁴⁰Ar by burial alteration, and at the same time acting as a support for the fundamental particles for the growth of authigenic fundamental particles that were found to incorporate Ar characterized by an excess of ⁴⁰Ar.

Key Words: Burial Diagenesis • Clay Fraction • Fundamental Particles • Illite-smectite • Mahakam Delta • Indonesia

This article has been cited by other articles:

				N. Clauer TOWARDS AN ISOTOPIC MODELING OF THE ILLITIZATION PROCESS BASED ON DATA OF ILLITE-TYPE FUNDAMENTAL PARTICLES FROM MIXED-LAYER ILLITE-SMECTITE Clays and Clay Minerals, February 1, 2006; 54(1): 116 - 127. [Abstract] [Full Text] [PDF]

				A. Lerman and N. Clauer LOSSES OF RADIOGENIC 40Ar IN THE FINE-CLAY SIZE FRACTIONS OF SEDIMENTS Clays and Clay Minerals, June 1, 2005; 53(3): 234 - 249. [Abstract] [Full Text] [PDF]