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Introduction
Published in Supriya Sengupta, Introduction to Sedimentology, 2017
Sedimentology deals with the processes and products of sedimentation. Sediments are produced either by disintegration and alteration of preexisting rocks or by precipitation from solution. The particles ejected out of volcanoes and the dust particles of cosmic origin also add to the sediment mass of the earth in a limited way. Sediments are transported by running water, wind or moving ice to various depositions environments. The process of sediment transportation is often accompanied by the production of rhythmic bedforms or more complex structures which, when well preserved, provide clues to the palaeoenvironment and palaeocurrent.
Correlation of the lithostratigraphic facies relationships and depositional environments of the uppermost Silurian through Lower Devonian strata across the central Darling Basin, western New South Wales, SE Australia
Published in Australian Journal of Earth Sciences, 2021
The Winduck Interval is composed of important uppermost Silurian through Lower Devonian strata in the Darling Basin sequence, which has conventional hydrocarbon exploration potential in sub-basins and troughs, and recognised reservoir and source rock possibilities (e.g. Alder et al., 1998; Bembrick, 1997a, 1997b; Blevin et al., 2007; Brown et al., 1982; Hus et al., 2006; Khalifa et al., 2015, 2017; Mullard, 1995; Neef, 2012; Sherwin, 1980; Willcox et al., 2003). Owing to the economic potential of the Winduck Interval, a detailed understanding of the subsurface stratigraphy and sedimentology is needed. The analysis of the lithostratigraphic unit architecture within the Winduck Interval can provide useful information on facies associations and history of depositional environments in the uppermost Silurian–Lower Devonian strata.
Tidal bore hydrodynamics and sediment processes: 2010–2016 field observations in France
Published in Coastal Engineering Journal, 2018
David Reungoat, Pierre Lubin, Xinqian Leng, Hubert Chanson
The tidal bore of the Garonne River (France) was comprehensively investigated between 2010 and 2016 as part of the Project Mascaret ANR-10-BLAN-0911. In addition, a field study was investigated in the Sélune River (France). The nature of the field observations was thorough, including hydrodynamics and turbulence, suspended sediment transport, and sedimentology. The aim of the paper is to review the key outcomes of the project, spanning over several years of observations and measurements, as well as developing a basic understanding of tidal-bore-affected estuarine zones in terms of temporal evolution of suspended sediment processes correlated to hydrodynamics, based upon large-scale field observations. A review of field data further shows a number of features common to all tidal bores, as well as some unique characteristics of each individual event.
Production and preservation of the smallest drumlins
Published in GFF, 2018
J. K. Hillier, Í. Ö. Benediktsson, T. P. F. Dowling, A. Schomacker
Neither sedimentology nor stratigraphy yet directly constrain drumlins’ elongation during surge-cycles. Till fabrics and bulk densities indicate that inter-drumlin areas have experienced higher maximum effective stresses (~100 kPa), argued to represent quiescent periods under the assumption of effective and channelized drainage at these times (McCracken et al. 2016). Then, as in other models (e.g., Hindmarsh 1998; Chapwanya et al. 2011), increased effective shear stresses are taken to indicate higher rates of sediment transport. The basal stress distribution is asserted to be compatible with a crevasse pattern at the ice front, which is strongly related to the spatial pattern of the drumlins (Johnson et al. 2010; Benediktsson et al. 2016; McCracken et al. 2016), but the mechanics of causal relationship remain conjectural. The available observations have been consolidated and reconciled into a conceptual model (Johnson et al. 2010; Jónsson et al. 2014; Benediktsson et al. 2016; McCracken et al. 2016), an extreme precis of which follows: although sediment transport mechanisms are not uniquely constrained, surges deposit drapes of till everywhere, then in each intervening quiescent period there is erosion in the inter-drumlin areas, processes that combine to lead to increases in H and L but a decrease in W. A mathematical model has been developed to formalise this (Iverson et al. 2017). GPR data (Lamsters et al. 2016) and the Múlajökull drumlins’ proximity to the LIA terminal moraine dictate that these models are based on, and therefore most directly constrain, near-margin (i.e., within <1–2 km) drumlin formation.