Core from Cid Formation - Mudstone member: Union County, NC

Select section of core from Core Hole 1 (CH-1), Arsenic research station, Union County (Photograph from NCDENR-DWQ). 


According to the geologic core descriptions in (Abraham, 2009) of Core Hole 1 (CH-1), Regolith is present from 0 – 31 feet, Transition zone is present from 31 – 61.5 feet and Bedrock is present from 61.5 feet to bottom of boring at 153.5 feet depth.


Dominant rock types present in core include: thinly bedded tuffaceous mudstone with lesser felsic tuff and sandstone.  These are typical lithologies for the Mudstone member of the Cid Formation.  Original sedimentary bedding is present generally perpendicular to core length.  The dip of original bedding measured from outcrops in the immediate vicinity of the area ranged from 10 – 40 degrees from the horizontal.


Formation or Unit: Cid Formation – Mudstone member

Sequence: Albemarle sequence

Terrane: Carolina terrane

Cid Mudstone core
Select section of core from Core Hole 1 (CH-1), Arsenic research station, Union County (Photograph from NCDENR-DWQ).  Cid Mudstone core
Select section of core from Core Hole 1 (CH-1), Arsenic research station, Union County (Photograph from NCDENR-DWQ).  Cid mudstone core
Select section of core from Core Hole 1 (CH-1), Arsenic research station, Union County (Photograph from NCDENR-DWQ).  Cid mudstone core

Select section of core from Core Hole 1 (CH-1), Arsenic research station, Union County (Photograph from NCDENR-DWQ). 

Close-up of core section with sandstone interlayer (left side of core) and tuffaceous mudstone (right side of core). Bedding is dipping at approximately 10 degrees.

Cid mudstone

Select section of core from Core Hole 1 (CH-1), Arsenic research station, Union County (Photograph from NCDENR-DWQ). 

Close-up of low angle fracture with sulfides (interpreted as pyrite) and calcite mineralization.

 

Cid mudstone core

Select section of core from Core Hole 1 (CH-1), Arsenic research station, Union County (Photograph from NCDENR-DWQ). 

Close-up of high angle fracture with sulfides (interpreted as pyrite) and iron oxide mineralization.

Cid mudstone