Shields Formation

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The image on the left is a conglomerate of the Shields Formation showing rounded white quartz pebbles.  The image on the right shows dark clasts of phyllite in the conglomerate.

Gray to white quartz pebble conglomerate and quartzose sandstone in graded beds was formerly mapped as Wilhite Formation (Neuman and Nelson, 1965).  Reconnaissance mapping supports the interpretation of Hadley and Nelson (1971) that the conglomerate most resembles rocks of the Shields Formation.  The conglomerate pebbles consist of oblate milky vein quartz as much as 1 inch long in a sandy matrix.  These distinctive rocks of the Walden Creek Group do not resemble any of the rocks within the Great Smoky Group or Snowbird Group.

     As opposed to the sub-angular blue quartz and white feldspar grains derived from granitic gneiss that make up the rocks of the Great Smoky Group, the conglomerate of the Shields Formation is composed mostly of rounded milky vein quartz.  These mature sediments were derived from metamorphosed rock that had abundant vein quartz and they were well rounded by running water.  To the west along Chilhowee Lake, similar quartz conglomerate contains blocks of limestone that range in diameter from centimeters to hundreds of meters.  The limestone has fossils that may be Paleozoic in age (Unrug and Unrug, 1990).  Rocks of the Shields Formation were probably deposited near the slope of the basin where mature continental sediments and blocks of shallow-water limestone were transported in submarine channels as debris flows.