HALITE  SALT  CASTS

 

One of the most distinctive and environmentally diagnostic (& rare, in my experience) features in the sedimentary record is a halite salt cast.

 

Halite (NaCl - sodium chloride) is a relatively common mineral - it is abundantly preserved in ancient evaporite successions and modern evaporite settings.  If seawater-soaked siliciclastic sediments dry out, halite crystals may form.  Halite crystals will almost always have nice cubic forms, but they can have embayed faces.  This mineral is readily soluble in water, so halite may precipitate and redissolve relatively quickly.  The crystal forms may become preserved in the sediments, as casts.  Preserved halite salt casts unquestionably demonstrate that the sedimentary environment was an evaporite setting.

 


 

Halite salt casts (field of view ~3.5 cm across) in friable mudshale from the Twist Gulch Formation (Middle Jurassic) of central Utah, USA.

Locality: loose piece from near small abandoned copper mine at Twist Gulch Formation-Flagstaff Limestone angular unconformity outcrop in Salina Canyon, central Utah, USA.

Collected & generously donated by Lee St. John & Mary Ellen St. John.

 



 

Halite salt casts (field of view ~17.7 cm across) in reddish silty mudshale from the Twist Gulch Formation (Middle Jurassic) of central Utah, USA.

Locality: loose piece from near small abandoned copper mine at Twist Gulch Formation-Flagstaff Limestone angular unconformity outcrop in Salina Canyon, central Utah, USA.

Specimen owned by Matthew Buxton.

 


 

Halite salt casts (above & below) (close-ups of specimen shown above) in reddish silty mudshale from the Twist Gulch Formation (Middle Jurassic) of central Utah, USA.

 

 


 

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