PARAGENESIS OF DIAGENETIC MINERALS IN THE ST. PETER SANDSTONE (ORDOVICIAN), WISCONSIN AND ILLINOIS

1979 ◽  
pp. 425-443 ◽  
Author(s):  
I. EDGAR ODOM ◽  
TIMOTHY N. WILLAND ◽  
RICHARD J. LASSIN
Keyword(s):  
Diagenetic Minerals

Chlorite interstratified with a 7 Å mineral: an example from offshore Norway and possible implications for the interpretation of the composition of diagenetic chlorites

Clay Minerals ◽  
1992 ◽  
Vol 27 (4) ◽  
pp. 475-486 ◽  
Author(s):  
S. Hillier ◽  
B. Velde
Keyword(s):  
Alternative Interpretation ◽  
High Porosity ◽  
X Ray Diffraction ◽  
Odd Order ◽  
Even Order ◽  
Diagenetic Minerals ◽  
Structural Formulae ◽  
Xrd Patterns ◽  
Diagenetic History ◽  
Pore Lining

AbstractX-ray diffraction (XRD) patterns of a pore-lining diagenetic chlorite (14 Å) from a reservoir sandstone, offshore Norway, show broad odd-order and sharp even-order basal reflections indicating that it contains 7 Å layers. Using NEWMOD, simulated XRD patterns with 15% 7 Å serpentine layers and a maximum crystallite thickness of 30 layers match the natural mineral well. Microprobe analyses of the 7 Å-14 Å mineral indicate that it is Fe-rich and aluminous suggesting that it is interstratified berthierine-chamosite. Apparent octahedral vacancies, however, suggest a significant dioctahedral component, and an alternative interpretation is interstratified kaolinite-chlorite. Indeed, chemical analyses of the mineral suggest a mixture of chlorite with 15% kaolinite, precisely the proportion of 7 Å layers indicated by XRD. Two other examples from the literature, previously identified as diagenetic chlorite, are probably also 7 Å-14 Å interstratified minerals, and the proportion of 7 Å layers indicated by XRD is also correlated with their structural formulae, if the 7 Å layers are, in fact, kaolinitic. This type of interstratification could explain why Fe-rich diagenetic chlorites appear to be compositionally distinct from metamorphic chlorites. The structure and chemistry of the Norwegian chlorite tend to support the idea that pore-lining chlorites form early in the diagenetic history, inhibiting the precipitation of later diagenetic minerals, and hence preserving abnormally high porosity at greater depths.

Research on Diagenetic Facies Based on Diagenetic Effect in the Low Permeability Sandstone Reservoir - A Case from C81 Reservoir in Huanjiang Region, Ordos Basin

2014 ◽  
Vol 522-524 ◽  
pp. 1274-1279
Author(s):  
Chun Wang ◽  
Zhi Guo Jin ◽  
Cheng Zhi Liu
Keyword(s):  
Physical Properties ◽  
Ordos Basin ◽  
Physical Property ◽  
Low Permeability ◽  
Thin Sections ◽  
Diagenetic Minerals ◽  
Calcite Cementation ◽  
Diagenetic Facies ◽  
Pore Types ◽  
Feldspar Dissolution

The research is carried out on diagenetic minerals, pore types and its impact on the physical properties in Huanjiang C81reservoir of Ordos basin, which is based on reservoir physical property test, thin sections observation and scanning electron microscopy. Several minerals closely associated with reservoir physical properties are identified from diagenetic effect views. It results in that a classification is proposed for the diagenetic facies, consisting of four kinds of diagenetic facies: ferroan calcite cementation facies, hydromica/kaolinite cementation facies, chlorite coating facies and feldspar dissolution facies. The study of C81reservoir in Huanjiang region shows that this scheme is favorable to estimate low permeability reservoir, the result shows fairly good consistency with the distribution of physical property of wells.

Iron-Rich Diagenetic Minerals are Biomarkers of Microbial Activity in Antarctic Rocks

2003 ◽  
Vol 20 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Jacek Wierzchos ◽  
Carmen Ascaso ◽  
Leopoldo García Sancho ◽  
Allan Green
Keyword(s):  
Microbial Activity ◽  
Diagenetic Minerals

U-series disequilibria in early diagenetic minerals from Lake Magadi sediments, Kenya: Dating potential

1992 ◽  
Vol 56 (3) ◽  
pp. 1331-1341 ◽  
Author(s):  
Christian Goetz ◽  
Claude Hillaire-Marcel
Keyword(s):  
Lake Magadi ◽  
Diagenetic Minerals

scholarly journals Predictive diagenetic clay-mineral distribution in siliciclastic rocks as a tool for identifying sequence boundaries in non-marine successions: the Coalspur Formation, west-central Alberta

Geologos ◽  
2009 ◽  
Vol 15 (3-4) ◽  
pp. 169-180 ◽  
Author(s):  
Ahmed Khidir ◽  
Octavian Catuneanu
Keyword(s):  
Clay Mineral ◽  
Secondary Porosity ◽  
Mineral Distribution ◽  
Sequence Stratigraphic ◽  
West Central ◽  
Stratigraphic Framework ◽  
Mineral Assemblages ◽  
Diagenetic Minerals ◽  
Siliciclastic Rocks ◽  
Sequence Boundaries

Predictive diagenetic clay-mineral distribution in siliciclastic rocks as a tool for identifying sequence boundaries in non-marine successions: the Coalspur Formation, west-central AlbertaThe study of upper Cretaceous-lower Tertiary fluvial deposits of the Coalspur Formation in the Foothills region of west-central Alberta reveals that the distribution of early authigenic kaolinite has a well-defined relation to the sequence stratigraphic framework. In this context, it has been observed that the kaolin mineral content increases in sandstones lying below subaerial unconformities, which mark the most significant stratigraphic hiatuses and hence the sequence boundaries in fully fluvial successions. The increased abundance of authigenic kaolinite immediately below sequence boundaries may have been caused by the infiltration of meteoric water during times of subaerial erosion, resulting in the dissolution of unstable minerals (e.g., micas and feldspar) and the formation of kaolinite and secondary porosity. It is therefore suggested that the change in clay mineral assemblages in the stratigraphic section depends in part on the position of the analyzed sandstone samples relative to the sequence boundaries. In a larger context, the method of using authigenic clays to delineate depositional sequences in non-marine successions needs to be evaluated on a case-by-case basis, as the diagnostic early diagenetic minerals underlying the sequence boundary may change as a function of palaeoclimate and also as a function of late diagenetic processes.

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