page_title: Syneresis crack
hierarchical_section_title: Syneresis crack
caption_attribution_description: English: Synaresis cracks in the Random Formation, Thornlea, Trinity Bay, Newfoundland
context_page_description: Syneresis cracks are a sedimentary structure developed by the shrinkage of sediment without desiccation – not to be confused with desiccation cracks. Syneresis is the expulsion of a liquid from a gel-like substance. Syneresis cracks are formed by the contraction of clay in response to changes in the salinity of a liquid surrounding a deposit. The cracks can occur, for example, in mudstones deposited between two beds of sandstone. The markings would have been formed subaqueously on the bedding surface and could resemble desiccation mudcracks, but are not continuous and vary in shape. They commonly occur in thin mudstones interbedded with sandstones, as positive relief on the bottom of the sandstone, or as negative relief on the top of the mudstone. Subaqueous shrinkage cracks can develop on and through a surface that has been continuously covered in water. Syneresis cracks in some shales and lime mudstones may initially be preserved as small cavities, which then usually fill with silt and sand from either the overlying or underlying beds and laminae.
  Usually there is no pattern to the cracks, and they do not connect to form geometric shapes.
context_section_description: Syneresis cracks (also known as subaqueous shrinkage cracks) are a  sedimentary structure developed by the shrinkage of sediment without desiccation – not to be confused with desiccation cracks.  Syneresis is the expulsion of a liquid from a gel-like substance.  Syneresis cracks are formed by the contraction of clay in response to changes in the salinity of a liquid surrounding a deposit. The cracks can occur, for example, in mudstones deposited between two beds of sandstone. The markings would have been formed  subaqueously on the bedding surface and could resemble desiccation mudcracks, but are not continuous and vary in shape. They commonly occur in thin mudstones interbedded with sandstones, as positive relief on the bottom of the sandstone, or as negative relief on the top of the mudstone.  Subaqueous shrinkage cracks can develop on and through a surface that has been continuously covered in water. Syneresis cracks in some shales and lime mudstones may initially be preserved as small cavities, which then usually fill with silt and sand from either the overlying or underlying beds and laminae.
  Usually there is no pattern to the cracks, and they do not connect to form geometric shapes.  Rather they are discontinuous and shaped in one of the following categories:
  polygonal - a closed plane figure, having three or more, usually straight, sides.
  sinuous - having many curves, bends, or turns.
  spindle - thickest in the middle and tapering at both ends.
  A cross section of any of these would reveal that they are U- or V-shaped.
caption: Synaresis cracks in lateral view in the Random Formation, Newfoundland and Labrador[1]
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