The rock record contains a rich variety of sedimentary surface textures on siliciclastic sandston... more The rock record contains a rich variety of sedimentary surface textures on siliciclastic sandstone, siltstone and mudstone bedding planes. In recent years, an increasing number of these textures have been attributed to surfi-cial microbial mats at the time of deposition, resulting in their classification as microbially induced sedimentary structures, or MISS. Research into MISS has developed at a rapid rate, resulting in a number of misconceptions in the literature. Here, we attempt to rectify these MISS misunderstandings. The first part of this paper surveys the stratigraphic and environmental range of reported MISS, revealing that contrary to popular belief there are more reported MISS-bearing rock units of Phanerozoic than Precambrian age. Furthermore, MISS exhibit a pan-environmental and almost continuous record since the Archean. Claims for the stratigraphic restriction of MISS to intervals prior to the evolution of grazing organisms or after mass extinction events, as well as claims for the environmental restriction of MISS, appear to result from sampling bias. In the second part of the paper we suggest that raised awareness of MISS has come at the cost of a decreasing appreciation of abiotic processes that may create morphologically similar features. By introducing the umbrella term 'sedimentary surface tex-tures', of which MISS are one subset, we suggest a practical methodology for classifying such structures in the geological record. We illustrate how elucidating the formative mechanisms of ancient sedimentary surface textures usually requires consideration of a suite of sedimentological evidence from surrounding strata. Resultant interpretations, microbial or non-microbial, should be couched within a reasonable degree of uncertainty. This approach recognizes that morphological similarity alone does not constitute scientific proof of a common origin, and reinstates a passive descriptive terminology for sedimentary surface textures that cannot be achieved with the current MISS lexicon. It is hoped that this new terminology will reduce the number of overly sensational and misleading claims of MISS occurrence, and permit the means to practically separate initial observation from interpretation. Furthermore, this methodology offers a scientific approach that appreciates the low likelihood of conclusively identifying microbial structures from visual appearance alone, informing the search for true MISS in Earth's geological record and potentially on other planetary bodies such as Mars.
The Preservation of Fluvial Sediments and Their Subsequent Interpretation, 2011
... recognized in stacked fluvial channel bodies or valley fills on the basis of changes in petro... more ... recognized in stacked fluvial channel bodies or valley fills on the basis of changes in petrography and paleoflow direction (Miall and Arush 2001 ... accord well with anecdotal evidence from villagers that floods do not cover interfluves along parts of the Yamuna River (Tandon et al. ...
... RESEARCH ARTICLES. MARINE INFLUENCE IN THE UPPER ORDOVICIAN JUNIATA FORMATION (POTTERS MILLS,... more ... RESEARCH ARTICLES. MARINE INFLUENCE IN THE UPPER ORDOVICIAN JUNIATA FORMATION (POTTERS MILLS, PENNSYLVANIA): IMPLICATIONS FOR THE HISTORY OF LIFE ON LAND. NEIL S. DAVIES * ,1 ,3 , MICHAEL C. RYGEL 2 and MARTIN R. GIBLING 1 ...
Special Paper 441: Resolving the Late Paleozoic Ice Age in Time and Space, 2008
... maximum glaciation took place during the latest Pennsylvanian and Early Permian. Although poo... more ... maximum glaciation took place during the latest Pennsylvanian and Early Permian. Although poorly constrained, Pennsylvanian (near the Bashkirian-Moscovian boundary; approximately ... individual cyclothems Cyclothems contain paleovalley fills, mature paleosols, and flooding ...
The coastal cliffs along the eastern shore of Chignecto Bay, Nova Scotia contain one of the fines... more The coastal cliffs along the eastern shore of Chignecto Bay, Nova Scotia contain one of the finest Carboniferous sections in the world. In 1843, Sir William Logan measured the entire section as the first project of the Geological Survey of Canada, and defined eight stratigraphic ...
The rock record contains a rich variety of sedimentary surface textures on siliciclastic sandston... more The rock record contains a rich variety of sedimentary surface textures on siliciclastic sandstone, siltstone and mudstone bedding planes. In recent years, an increasing number of these textures have been attributed to surfi-cial microbial mats at the time of deposition, resulting in their classification as microbially induced sedimentary structures, or MISS. Research into MISS has developed at a rapid rate, resulting in a number of misconceptions in the literature. Here, we attempt to rectify these MISS misunderstandings. The first part of this paper surveys the stratigraphic and environmental range of reported MISS, revealing that contrary to popular belief there are more reported MISS-bearing rock units of Phanerozoic than Precambrian age. Furthermore, MISS exhibit a pan-environmental and almost continuous record since the Archean. Claims for the stratigraphic restriction of MISS to intervals prior to the evolution of grazing organisms or after mass extinction events, as well as claims for the environmental restriction of MISS, appear to result from sampling bias. In the second part of the paper we suggest that raised awareness of MISS has come at the cost of a decreasing appreciation of abiotic processes that may create morphologically similar features. By introducing the umbrella term 'sedimentary surface tex-tures', of which MISS are one subset, we suggest a practical methodology for classifying such structures in the geological record. We illustrate how elucidating the formative mechanisms of ancient sedimentary surface textures usually requires consideration of a suite of sedimentological evidence from surrounding strata. Resultant interpretations, microbial or non-microbial, should be couched within a reasonable degree of uncertainty. This approach recognizes that morphological similarity alone does not constitute scientific proof of a common origin, and reinstates a passive descriptive terminology for sedimentary surface textures that cannot be achieved with the current MISS lexicon. It is hoped that this new terminology will reduce the number of overly sensational and misleading claims of MISS occurrence, and permit the means to practically separate initial observation from interpretation. Furthermore, this methodology offers a scientific approach that appreciates the low likelihood of conclusively identifying microbial structures from visual appearance alone, informing the search for true MISS in Earth's geological record and potentially on other planetary bodies such as Mars.
The Preservation of Fluvial Sediments and Their Subsequent Interpretation, 2011
... recognized in stacked fluvial channel bodies or valley fills on the basis of changes in petro... more ... recognized in stacked fluvial channel bodies or valley fills on the basis of changes in petrography and paleoflow direction (Miall and Arush 2001 ... accord well with anecdotal evidence from villagers that floods do not cover interfluves along parts of the Yamuna River (Tandon et al. ...
... RESEARCH ARTICLES. MARINE INFLUENCE IN THE UPPER ORDOVICIAN JUNIATA FORMATION (POTTERS MILLS,... more ... RESEARCH ARTICLES. MARINE INFLUENCE IN THE UPPER ORDOVICIAN JUNIATA FORMATION (POTTERS MILLS, PENNSYLVANIA): IMPLICATIONS FOR THE HISTORY OF LIFE ON LAND. NEIL S. DAVIES * ,1 ,3 , MICHAEL C. RYGEL 2 and MARTIN R. GIBLING 1 ...
Special Paper 441: Resolving the Late Paleozoic Ice Age in Time and Space, 2008
... maximum glaciation took place during the latest Pennsylvanian and Early Permian. Although poo... more ... maximum glaciation took place during the latest Pennsylvanian and Early Permian. Although poorly constrained, Pennsylvanian (near the Bashkirian-Moscovian boundary; approximately ... individual cyclothems Cyclothems contain paleovalley fills, mature paleosols, and flooding ...
The coastal cliffs along the eastern shore of Chignecto Bay, Nova Scotia contain one of the fines... more The coastal cliffs along the eastern shore of Chignecto Bay, Nova Scotia contain one of the finest Carboniferous sections in the world. In 1843, Sir William Logan measured the entire section as the first project of the Geological Survey of Canada, and defined eight stratigraphic ...
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