Chemostratigraphic and sedimentologic evolution of Wajid Group (Wajid Sandstone): An outcrop analog study from the Cambrian to Permian, SW Saudi Arabia

Yassin, Mohamed A.; Abdullatif, Osman

doi:10.1016/j.jafrearsci.2016.11.029

Cited by 12 publications

(1 citation statement)

References 27 publications

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“…Glaciers process all kinds of sediments and bedrock, slowly turning these into rock flour, and do not sort out the finer material (albeit, of course, with the exception of sediments from small alpine glaciers which are processed during a very short time, and produce deposits which would be more vulnerable to erosion and would be difficult to document in the rock record). In pre-Pleistocene diamictites which are interpreted to be glaciogenic and displaying outcrops over large areas, there is often no rock flour, contrary to Quaternary tills (Frakes 1979;Le Heron et al, 2005, 2006Yassin & Abdullatif, 2017;Molén 2017;Chen et al, 2021). Soft sediment clasts may be common (Deynoux, 1985b;Molén, 2017;Kennedy & Eyles, 2019, and sometimes clasts in diamictites have been pressed into underlying surfaces (Isbell et al, 2021), or the overlying sediment has been pressed down into the diamictite, or the diamictite has been pressed upwards into the overlying sediments (Cuneo et al, 1993;Isbell, 2010), i.e., features which frequently accompany SGF deposits (Shanmugam, 2012;Molén, 2017Molén, , 2023aVesely et al, 2018;Kennedy & Eyles, 2019Rodrigues et al, 2020;Kraft & Vesely, 2023).…”

Section: Diamict Structurementioning

confidence: 99%

Patterns, processes and models - an analytical review of current ambiguous interpretations of the evidence for pre-Pleistocene glaciations

Molén

2023

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Models (paradigms) and former interpretations have often been presupposed when conducting field research. In the 19th century diamictites were for the first time interpreted to have originated from ancient glaciations. These interpretations have to a large part prevailed in the geological community, although there has been much progress in the areas of sedimentology, glaciology and physical geography. The present work is an effort to find criteria which most clearly discriminate between geological features produced by different processes, mainly glaciation and mass flow, the latter predominantly sediment gravity flows. Geological features which have been interpreted to have formed by glaciation throughout pre-Pleistocene Earth history are compared to similar-appearing geological features formed by mass flow and tectonics, so as to uncover variations in the appearance between features resulting from these different processes. The starting point for this comparison is documentation of the appearance of Quaternary products of erosion and deposition, in order to discern the origin of older formations. It is shown that the appearance and origin of pavements, dropstones, valleys, small-scale landforms, surface microtextures and most other geological features may in some cases be equivocal, but in others the details are indicative of the process which generated the feature. Detailed geological field data which have been compiled by geologists from outcrops of pre-Pleistocene strata, more often than is considered in most papers, commonly point to a mass flow origin, mainly a sediment gravity flow origin, rather than a glaciogenic origin. A process of multiple working hypotheses or interpretations is therefore advocated, based mainly on a comparison of the appearance of features formed by different geological processes documented from different research disciplines. Instead of starting with current interpretations or models, this multiple working hypothesis or methodology helps to avoid confirmation bias and jumping to conclusions.

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