Clay Mineral Diagenesis and Thermal History of the Thonex Well, Western Swiss Molasse Basin

Schegg, Roland; Leu, W.

doi:10.1346/ccmn.1996.0440513

Cited by 14 publications

(9 citation statements)

References 30 publications

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“…Similar conditions have been observed in wells in the Swiss (Rybach, 1984;Schegg, 1994;Schegg and Leu, 1996;Schegg et al, 1997), German (Jacob and Kuckelkorn, 1977;Teichmueller and Teichmueller, 1986), and Austrian Molasse Basin and its fold and thrust belt (Sachsenhofer, 2001).…”

Section: Oligocene and Miocene Heat Flowssupporting

confidence: 70%

Evaluation of hydrocarbon generation and migration in the Molasse fold and thrust belt(Central Eastern Alps, Austria) using structural and thermal basin models

Gusterhuber

Hinsch²,

Sachsenhofer

2014

Bulletin

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The Molasse Basin represents the northern foreland basin of the Alps. After decades of exploration, it is considered to be mature in terms of hydrocarbon exploration. However, geological evolution and hydrocarbon potential of its imbricated southernmost part (Molasse fold and thrust belt) are still poorly understood. In this study, structural and petroleum systems models are integrated to explore the hydrocarbon potential of the Perwang imbricates in the western part of the Austrian Molasse Basin.The structural model shows that total tectonic shortening in the modeled north-south section is at least 32.3 km (20.1 mi) and provides a realistic input for the petroleum systems model. Formation temperatures show present-day heat flows decreasing toward the south from 60 to 41 mW/m 2 . Maturity data indicate very low paleoheat flows decreasing southward from 43 to 28 mW/m 2 . The higher present-day heat flow probably indicates an increase in heat flow during the Pliocene and Pleistocene.Apart from oil generated below the imbricated zone and captured in autochthonous Molasse rocks in the foreland area, oil stains in the Perwang imbricates and oil-source rock correlations argue for a second migration system based on hydrocarbon generation inside the imbricates. This assumption is supported by the models presented in this study. However, the model-derived low transformation ratios (<20%) indicate a charge risk. In

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Section: Oligocene and Miocene Heat Flowssupporting

confidence: 70%

Evaluation of hydrocarbon generation and migration in the Molasse fold and thrust belt(Central Eastern Alps, Austria) using structural and thermal basin models

Gusterhuber

Hinsch²,

Sachsenhofer

2014

Bulletin

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“…In this well, the disappearance of smectite (R0), which marks the transition between zones R0 and R1, took place at a maximum temperature of 160ºC (Fig. 8), much higher than the values of 75À120ºC reported in the literature (Hoffman & Hower, 1979;Ś rodoń & Eberl, 1984;Schegg & Leu, 1996;Uysal et al, 2000b;Abid et al, 2004).…”

Section: Thermal Modelling and Clay Mineralogymentioning

confidence: 56%

“…oil or gas generation and possible paths of hydrocarbon migration (Tissot et al, 1987;Waples et al, 1992;Yahi et al, 2001). Temperature values obtained from these models have frequently been related to clay mineral distribution in diagenetic series (Pearson & Small, 1988;Glansman et al, 1989;Velde & Lanson, 1993;Schegg & Leu, 1996) and to organic maturity indicators, mainly vitrinite reflectance (Gier, 2000). Although a direct correspondence between time/ temperature and organic maturity exists in many sedimentary basins, correspondence with clay mineral composition is not as common, as it depends on several additional factors (Scotchman, 1987;Merriman, 2005).…”

mentioning

confidence: 99%

Thermal models and clay diagenesis in the Tertiary-Cretaceous sediments of the Alava block (Basque-Cantabrian basin, Spain)

Aróstegui¹,

Sangüesa²,

Nieto³

et al. 2006

Clay miner.

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AB ST R ACT : Diagenesis in the Cretaceous and Tertiary sediments of the Alava Block (BasqueCantabrian basin) has been studied using the clay mineralogy (X-ray diffraction) of cuttings from three representative wells of a NÀS cross-section. More than 5500 m of various lithologies (marls, mudstones and sandstones) have been drilled in the northern part of the domain, and 2100 m in the southern zone. The illitization of smectite and the disappearance of kaolinite, due to diagenesis, are the most characteristic features in the northern well. Evolution of smectite to illite has been differentiated into four zones, from top to bottom of the series, each showing specific I-S interstratified clay assemblages. The disappearance of smectite and the distribution of kaolinite in the other two wells are explained based on source-area considerations. Burial and thermal history have been reconstructed, revealing a northward increase in thermal flow until the Oligocene (Alpine orogeny paroxysm). In the northern well, the thermal model suggests temperatures of 160 and 270ºC for the disappearance of smectite (R0) and illite-smectite (I-S) mixed-layer R1 clay minerals, respectively. The disappearance of kaolinite is related to a temperature of 230ºC, a temperature never attained in the other two wells. Retardation of these processes, in relation to temperature values in the literature, is a consequence of the poor reactivity of marly lithologies, due to the low availability of cations. In this regard, the scarcity of reactants (K-bearing phases) and the absence of pathways (low permeability) for their access and circulation imply that illitization could have taken place in a closed system, by diffusion, on a very small scale, i.e. that of the original smectite grains.

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“…It has been suggested that the temperature that reflects the appearance of R1 I/S during the smectite illitization process is generally around 100 °C while the transition temperature from R1 to R3 I/S can be up to ca. 180 °C [48,50,[53][54][55]. In this study, most of the studied samples have the R1 ordered I/S, except for only one sample that has the R3 ordered I/S (Table 1) indicating that the paleo-diagenetic temperature for the studied samples could have been up to 180 °C but for most of the samples, this value ranges from 100 to 180 °C.…”

Section: Implications For Paleo-diagenetic Temperaturementioning

confidence: 56%

“…Temperature and fluid chemistry thus should be the dominant factors that would have influenced the formation of I/S in this study. Many studies have focused on the diagenetic temperature during the burial process, using the evolution of smectite illitization (especially the percentages of smectite layers within I/S) [48,50,[53][54][55]. In the XRD patterns for the EG-saturated clay fractions, as smectite layers decrease in I/S, the peaks at 9 Å, as well as peaks at 5 Å, become sharp and narrow showing a trend towards illite and indicating a progressive increment in temperature (Figure 7).…”

Section: Implications For Paleo-diagenetic Temperaturementioning

confidence: 99%

Clay Mineralogy of Coal-Hosted Nb-Zr-REE-Ga Mineralized Beds from Late Permian Strata, Eastern Yunnan, SW China: Implications for Paleotemperature and Origin of the Micro-Quartz

et al. 2016

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Abstract:The clay mineralogy of pyroclastic Nb(Ta)-Zr(Hf)-REE-Ga mineralization in Late Permian coal-bearing strata from eastern Yunnan Province; southwest China was investigated in this study. Samples from XW and LK drill holes in this area were analyzed using XRD (X-ray diffraction) and SEM (scanning electronic microscope). Results show that clay minerals in the Nb-Zr-REE-Ga mineralized samples are composed of mixed layer illite/smectite (I/S); kaolinite and berthierine. I/S is the major component among the clay assemblages. The source volcanic ashes controlled the modes of occurrence of the clay minerals. Volcanic ash-originated kaolinite and berthierine occur as vermicular and angular particles, respectively. I/S is confined to the matrix and is derived from illitization of smectite which was derived from the original volcanic ashes. Other types of clay minerals including I/S and berthierine precipitated from hydrothermal solutions were found within plant cells; and coexisting with angular berthierine and vermicular kaolinite. Inferred from the fact that most of the I/S is R1 ordered with one case of the R3 I/S; the paleo-diagenetic temperature could be up to 180˝C but mostly 100-160˝C. The micro-crystalline quartz grains (<10 µm) closely associated with I/S were observed under SEM and were most likely the product of desiliconization during illitization of smectite.

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Clay Mineral Diagenesis and Thermal History of the Thonex Well, Western Swiss Molasse Basin

Cited by 14 publications

References 30 publications

Evaluation of hydrocarbon generation and migration in the Molasse fold and thrust belt(Central Eastern Alps, Austria) using structural and thermal basin models

Evaluation of hydrocarbon generation and migration in the Molasse fold and thrust belt(Central Eastern Alps, Austria) using structural and thermal basin models

Thermal models and clay diagenesis in the Tertiary-Cretaceous sediments of the Alava block (Basque-Cantabrian basin, Spain)

Clay Mineralogy of Coal-Hosted Nb-Zr-REE-Ga Mineralized Beds from Late Permian Strata, Eastern Yunnan, SW China: Implications for Paleotemperature and Origin of the Micro-Quartz

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