Quartz-grain surface textures: evidence for a tropical climate during the Middle Pennsylvanian in eastern Canada

1985 ◽  
Vol 22 (5) ◽  
pp. 786-790 ◽  
Author(s):  
A. Murray D'Orsay ◽  
H. W. van de Poll
Keyword(s):  
Surface Characteristics ◽  
Tropical Climate ◽  
Alluvial Fan ◽  
Microscope Examination ◽  
Eastern Canada ◽  
Surface Textures ◽  
Tropical Environments ◽  
Head Formation ◽  
Grain Surface ◽  
Quartz Grains

Scanning electron microscope examination of quartz grains separated from conglomerates in an alluvial fan sequence within the Pennsylvanian Fowler Head Formation of Nova Scotia revealed surface characteristics that are typical of those obtained from modern tropical environments. This evidence suggests that a similar tropical climate may have existed in eastern Canada during Middle Pennsylvanian time.

Surface textures and rounding of quartz sand grains on intertidal sandbars, Bay of Fundy, Nova Scotia

1979 ◽  
Vol 16 (11) ◽  
pp. 2071-2085 ◽  
Author(s):  
Gerard V. Middleton ◽  
Patricia M. Davis
Keyword(s):  
Electron Microscope ◽  
Coastal Erosion ◽  
Source Material ◽  
Bay Of Fundy ◽  
Microscope Examination ◽  
Surface Textures ◽  
Wide Range ◽  
Source Materials ◽  
Quartz Grains

Intertidal sands in the Minas Basin are mineralogically immature, and are generally medium grained and moderately well sorted. Quartz grains show a wide range of roundness: mean roundness is subangular, but rounded to well rounded grains are also present. The sands are derived mainly from coastal erosion of Pleistocene tills and outwash and Triassic sandstones.Scanning electron microscope examination of the surface textures of more than 40 samples of source materials and tidal sands reveals that although many of the textures are relict, tidal sands show high, smoothed surfaces with non-oriented V's, and low areas with 'patchy growths', neither of which are present on source sands. Rounding of grains is undoubtedly taking place in the tidal environments, but much of the roundness is inherited from Triassic source material, and new surface textures are developed most rapidly on grains already partly rounded.Average distances of grain transport in the layer of sand moving on the bar surface is of the order of 1 m per tidal cycle, and allowing for reworking of the entire mass of sand in the bars, this results in a long term transport rate of only about 10 m per year. For the distance of transport, sediment transport by tides is probably more efficient at rounding sand grains than transport by rivers, but less efficient than transport by waves or wind. Geologically long periods of reworking by tides would be necessary to produce texturally supermature sands.

Quartz surface microtextures and grain-size characteristics of Quaternary sediments in the Porcupine Strand area of coastal Labrador, Newfoundland, Canada

1983 ◽  
Vol 20 (3) ◽  
pp. 377-387 ◽  
Author(s):  
R. J. Rogerson ◽  
H. M. Hudson
Keyword(s):  
Grain Size ◽  
Distribution Data ◽  
Quartz Surface ◽  
Quaternary Sediments ◽  
Multivariate Statistical ◽  
Surface Textures ◽  
Systematic Fashion ◽  
Statistical Pattern ◽  
Quartz Grains ◽  
Scanning Electron

Sand-sized quartz grains from five Quaternary environments on the coast of Labrador were scrutinized under a scanning electron microscope. Various surface textural characteristics defined in previous literature were noted and "counted" in a systematic fashion. Multivariate statistical analysis of the data reveals that certain groups of surface textures provide for significant environmental identification, but no single surface texture is unique to any one environment. Absolute recognition of a particular environment from the presence of "diagenetic" features on several grains is not recommended for areas such as this. Yet the statistical pattern of scores for some features results in a position of individual samples and groups similar to the patterns obtained from the analysis of grain-size distribution data. The glacial environment appears to be no harder to define than most others in this type of analysis.

Mid-Wisconsinan eolian deposits of the Kittigazuit Formation, Tuktoyaktuk Coastlands, Northwest Territories, Canada

1997 ◽  
Vol 34 (11) ◽  
pp. 1421-1441 ◽  
Author(s):  
Scott R. Dallimore ◽  
Stephen A. Wolfe ◽  
John V. Matthews Jr. ◽  
Jean-Serge Vincent
Keyword(s):  
Mass Spectrometry ◽  
Late Quaternary ◽  
Surface Characteristics ◽  
Radiocarbon Dates ◽  
Glacial Ice ◽  
Alluvial Sediments ◽  
Summer Climate ◽  
Eolian Deposits ◽  
Glaciogenic Sediments ◽  
Grain Surface

The Kittigazuit Formation is a late Quaternary sand unit commonly observed throughout the Tuktoyaktuk Coastlands and in subbottom sediments of the southern Beaufort Shelf. Stratigraphic and sedimentology data, including sedimentary structures, grain-surface characteristics, and heavy and light mineralogy, assist in characterizing the deposit and indicate that it is eolian in origin. Plant and arthropod macrofossils suggest that, although the summer climate during deposition was as warm or slightly warmer than today, conditions were likely more arid. Permafrost is interpreted as being widespread during deposition. Accelerator mass spectrometry radiocarbon dates indicate that the Kittigazuit Formation was deposited between 37 and 33 ka BP. The unit is therefore interpreted as a Mid-Wisconsinan eolian dune deposit, formed by reworking of underlying alluvial sediments of the Kidluit Formation under nonglacial conditions. Glaciogenic sediments overlying the Kittigazuit Formation indicate that glacial ice covered the Tuktoyaktuk Peninsula, Richards Island, and parts of the Beaufort Shelf sometime after 33 ka BP, whereas several terrestrial dates indicate that the area may have been ice free by about 20 ka BP.

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