The Castlegate Sandstone and The Miners

On my recent field trip to Utah with the MYRES group we also visited an outcrop of the Castlegate Sandstone (Book Cliffs – click here for more information). This particular section shows fluvial sandstones that are intercalated with abundant coal intervals. Hajek and Heller (2012) described this units as follows : “The Castlegate Sandstone was deposited in a foreland basin by rivers that flowed eastward off of the adjacent Sevier Orogenic Belt into the Cretaceous Interior Seaway (Fouch et al., 1983). The base of the section is considered to be the Castlegate sequence boundary (CSB), across which fluvial Castlegate Sandstone deposits are juxtaposed atop fluvio-deltaic sandstones of the Blackhawk Formation (Campanian; Fouch et al. 1983). In its type section just north of Helper, Utah, the Castlegate Sandstone is divided into three informal units (Fouch et al. 1983): the lower, cliff-forming sandstone-dominated interval, widely interpreted as resulting from braided-river deposition (e.g., Chan and Pfaff 1991; Miall 1994; Adams and Bhattacharya 2005; McLaurin and Steel 2007); the middle mudstone-dominated interval with isolated sandstone channel-belt deposits, interpreted as sinuous single-thread river deposits (e.g., Chan and Pfaff 1991); and the upper “Bluecastle Tongue” of the Castlegate Sandstone, a sandstone-dominated, cliff-forming interval. In general the Castlegate Sandstone in its type area is wholly fluvial in origin; however, evidence of tidal and brackish water influence has been reported in the middle Castlegate interval in the type locality (McLaurin and Steel 2000).”

MYRESV participants attacking the outcrop! Picture by Lorena Moscardelli

Castlegate Sandstone - Fluvial sandstones intercalated with abundant coal intervals. Picture by Lorena Moscardelli

Hajek and Heller (2012) used LIDAR images of fully preserved bar clinoforms from the Castlegate Sandstone to measure clinoform heights and used these measurements as a proxy for paleoflow depth.

This particular outcrop is located near a power plant and several coal mines that have been operating in this region for decades. Obviously, the Castlegate Sandstone with its abundant coal intervals is an important component of the energy and economic equation in this region. However, we should not forget that the coal business is not only dirty (from an environmental perspective) but also dangerous (in a more tangible way). On March 8, 1924 an explosion occurred in the Castle Gate No.2 Mine that instantly killed 171 miners and one emergency worker. The majority of the miners were immigrants who left 241 children behind and 25 expectant mothers. Unfortunately, this was not the last tragedy in this region and on July 31, 2000 an explosion on the Willow Creek Mine took the lives of 2 miners sending 8 more to the hospital. After this last explosion, the Willow Creek Mine was closed for good. Energy has a price that sometimes is just too high.

Memorial Willow Creek Mine Explosion - July 31, 2000

Castle Gate Mine Disaster - March 8, 1924 

References:

Hajek and Heller (2012) Flow-depth scaling in alluvial architecture and nonmarine sequence stratigraphy: Example from the Castlegate Sandstone, Central Utah, USA. Journal of Sedimentary Research, v. 82, 121-130