During authigenic mineral
formation, ash assimilated some elements from the surrounding environment, whereas the set of assimilated elements has been considerably different in the Kinnekulle and BII bentonites.
In such contexts, glauconite is an authigenic mineral
developed as pelletal facies (mud coprolites, foraminiferal tests and mineral debris), and less frequently as films growing in holes, cracks and borings on hardgrounds and omission surfaces that may be associated with phosphates (e.g., Odin and Letolle, 1981; Odin and Matter, 1981; Fischer, 1990; Jimenez-Millan et al., 1998; Wigley and Compton, 2007).
3e), although truncation and mechanical reworking can also separate stages of authigenic mineral
The clastic matrix is composed mainly of silt-size quartz and illite, the minor clastic minerals are feldspars and chlorite, pyrite is a rather common authigenic mineral
. The organic matter represents a mixture of high-molecular polyfunctional organic compounds, the real structure of which is yet a subject of studies.
However, the complicated geological conditions and resultant authigenic mineral
structures described in these publications resemble, but do not equal those determined and described in the present study.
However, there is uncertainty regarding a) whether the geochemical system is open or closed during diagenesis in sedimentary basins (Bjorkum & Gjelsvik, 1988; Bjorlykke & Jahren, 2010; Gluyas&Coleman, 1992; Sullivan et al., 1990; Worden & Barclay, 2000; Usman et al., 2018), and b) the origin and formation process of authigenic minerals
, including clay minerals, and carbonate and quartz cements in sandstone (Barclay & Worden, 2000; Dowey, 2012;Worden & Morad, 2000).
Wang, "Climatic implication of authigenic minerals
formed during pedogenic weathering processes," Earth Science, vol.
Precipitation occurs when the pore water reaches saturation and forms authigenic minerals
, such as kaolinite, chlorite, illite, and authigenic quartz, which can occupy pore space, block throats, and thus reduce the quality of the reservoir properties.
The ash particles are covered by secondary precipitates, and bonds between the particles are generated by interlocking needle- and lath-shape authigenic minerals
that can be identified by crystallite morphology and chemical composition as hydrocalumite and ettringite.
The presence of authigenic minerals
like kaolinite, gibbsite, boehmite and dickite may owe to the decomposition and prolonged moderate to intense insitu leaching of alumino-silicates present in Mesozoic rocks andpart of Permian rocks.
Phyllosilicates and [Fe.sup.3+]-oxyhydroxides dominate among the authigenic minerals
. The resulting structure and chemical composition of the newly formed crystalline and amorphous minerals is controlled by the chemistry of the parent rock and its constituents (Fig.
In Authigenic Minerals
of Baltic Terrigenous Sediments (Pirrus, E., ed.), pp.