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Soft-sediment deformation structures in siliciclastic sediments: an overview

Loon A. J.

Geologos

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2009

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Vol. 15, No. 1

3--55

EN

Deformations formed in unconsolidated sediments are known as soft-sediment deformation structures. Their nature, the time of their genesis, and the state in which the sediments occured during the formation of soft-sediment deformation structures are responsible for controversies regarding the character of these deformations. A definition for soft sediment deformation structures in siliciclastic sediments is therefore proposed. A wide variety of soft-sediment deformations in sediments, with emphasis on deformations in siliciclastic sediments studied by the present author, are described. Their genesis can be understood only if their sedimentary context is considered, so that attention is also paid to the various deformational processes, which are subdivided here into (1) endogenic processes resulting in endoturbations; (2) gravity-dominated processes resulting in graviturbations, which can be subdivided further into (2a) astroturbations, (2b) praecipiturbations, (2c) instabiloturbations, (2d) compagoturbations and (2e) inclinaturbations; and (3) exogenic processes resulting in exoturbations, which can be further subdivided into (3a) bioturbations - with subcategories (3a’) phytoturbations, (3a’’) zooturbations and (3a’’’) anthropoturbations - (3b) glaciturbations, (3c) thermoturbations, (3d) hydroturbations, (3e) chemoturbations, and (3f) eoloturbations. This subdivision forms the basis for a new approach towards their classification. It is found that detailed analysis of soft-sediment deformations can increase the insight into aspects that are of importance for applied earth-scientific research, and that many more underlying data of purely scientific interest can, in specific cases, be derived from them than previously assumed. A first assessment of aspects that make soft-sediment deformation structures in clastic sediments relevant for the earth sciences, is therefore provided.

2

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

Khidir Ahmed, Catuneanu Ovtavian

Geologos

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2009

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Vol. 15, No. 3-4

169--180

EN

The 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.

3

Wpływ kationowych związków powierzchniowo czynnych na wielkość cząstek i polidyspersyjność strąconych krzemionek aktywnych

Jesionowski T., Krysztafkiewicz A., Skrzypczak A.

Prace Naukowe Instytutu Technologii Organicznej i Tworzyw Sztucznych Politechniki Wrocławskiej. Konferencje

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2000

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Vol. 48, nr 22

273-276

PL

Wysoko zdyspergowane substancje proszkowe znajdują szerokie zastosowanie w produkcji wysoko przetworzonych materiałów w przemyśle chemicznym, spożywczym, przetwórczym oraz kosmetycznym. Do najważniejszej grupy tego typu produktów należą syntetyczne krzemionki o dużym stopniu rozdrobnienia. Krzemionkę uwodnioną otrzymuje się z roztworu metakrzemianu sodu przez wytrącenie za pomocą czynnika kwasowego (np. rozcieńczonego kwasu lub bezwodnika kwasowego). Dodatkowo proces strącania wymaga zastosowania czynników, które ukierunkowują go na uzyskanie osadów wysoko zdyspergowanych. Do nich należą min. związki powierzchniowo czynne z grupy czwartorzędowych soli imidazoliowych.

EN

The highly dispersed silicas were obtained using a precipitation technique. For the modification of silica surface the cationic imidazolium surfactants were applied. The precipitated silicas were subjected to basic physicochemical. structural, and microscopic evaluation, and their surface properties were examined. Effects of the imidazolium surfactants on silica particles size distributions and on hydrophobicity of silica surface were tested.

4

Hydrofobizacja powierzchni krzemionek za pomocą kationowych związków powierzchniowo czynnych z ugrupowaniem imidazoliowym

Krysztafkiewicz A., Jesionowski T., Skrzypczak A.

Prace Naukowe Instytutu Technologii Organicznej i Tworzyw Sztucznych Politechniki Wrocławskiej. Konferencje

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2000

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Vol. 48, nr 22

285-288

PL

Powierzchnię krzemionek uwodnionych o dużym stopniu rozdrobnienia cechuje charakter hydrofilowy oraz kwasowy. Powierzchnia ma wyraźnie elektroujemny charakter: Istotnym problemem jest hydrofobizacja powierzchni oraz zmiana oddziaływań kinetycznych napełniacz - czynnik hydrofobizujący. Celem uzyskania krzemionek o charakterze hydrofilowo-hydrofobowym oraz hydrofobowym zastosowano czwartorzędowe związki imidazoliowe z różnymi podstawnikami i anionami.

EN

The highly dispersed silicas were obtained using a precipitation technique. For the modification of silica surface the cationic surfactants with different imidazolium groups were applied The precipitated silicas were subjected to base physicochemical. structural, and microscopic evaluation, and their surface properties were examined Effects of the imidazolium surfactants on silica agglomerates and aggregates size distributions and on zeta potential of silica surface were tested