Green River Formation (Mahogany Zone)
The Green River Formation is part of the Piceance basin and one of the largest oil shale reserves in the world. While part of the Piceance basin; this layer stretches over three states including Wyoming, Utah, and the focus of this project; Colorado. (Dyni 2008.)
Of this formation the Mahogany zone is an area of great interest due to the large quantity of high grade oil it contains. This figure shows the Mahogany zone in relation to the Parachute Creek Green River Formation. The black dots indicating test holes used to determine the potential oil yields of the area (Johnson et al 2009.)
The Green River Formation was deposited during the Eocene epoch (Johnson et al 2009.) This epoch lasted from 55.8 million years ago to 33.9 (Polly et al 2011.) The Mahogany Zone derives its name from the redish brown color of the rock that is the result of a rich-kerogen content (Tuttle et al 1983.)
Of this formation the Mahogany zone is an area of great interest due to the large quantity of high grade oil it contains. This figure shows the Mahogany zone in relation to the Parachute Creek Green River Formation. The black dots indicating test holes used to determine the potential oil yields of the area (Johnson et al 2009.)
The Green River Formation was deposited during the Eocene epoch (Johnson et al 2009.) This epoch lasted from 55.8 million years ago to 33.9 (Polly et al 2011.) The Mahogany Zone derives its name from the redish brown color of the rock that is the result of a rich-kerogen content (Tuttle et al 1983.)
Layering
The Green River formation is made up of a number of layers indicative of shallow water deposition by the ancient Lake Uinta (Tuttle et al 1983.) Major layers of sediments include oolitic grindstones, packstones, oil shale, and mudstone (Tuttle et all 1983). Additionally limestone, marlstone mudstone, siltstone sandstone, conglomerate, volcanic tuff, and trona are also present in the Eocene Green River Formation (Textoris 1963).
This ancient lake shares the name of the Uinta aquifer that is located in this area. This aquifer is in close proximity to the Green River Formation. This figure shows the aquifer in relation to the other layers. More information on the Uinta aquifer and others can be found here.
This ancient lake shares the name of the Uinta aquifer that is located in this area. This aquifer is in close proximity to the Green River Formation. This figure shows the aquifer in relation to the other layers. More information on the Uinta aquifer and others can be found here.
Green River Formation Resources
The first figure on this page shows an area known as the Parachute Creek Green River Formation with a number of black dots that are areas of resource assessment. From this assessment there is an estimated 1.525 trillion barrels of oil located in this area. This assessment disregards richness and instead focuses on a total estimate (Johnson et al 2009.)
The figure shown on the left here shows 17 layers that were sampled throughout the area. Top bed 44 was assessed at 189.7 billion barrels and the Mahogany zone 191.7 (Johnson et al 2009.)
More information regarding this assessment can be found in this document published by the USGS. Assessment of In-Place Oil Shale Resources of the Green River Formation, Piceance Basin, Western Colorado
Another area of possible resources are located in the Mancos Shale of the same area.
The figure shown on the left here shows 17 layers that were sampled throughout the area. Top bed 44 was assessed at 189.7 billion barrels and the Mahogany zone 191.7 (Johnson et al 2009.)
More information regarding this assessment can be found in this document published by the USGS. Assessment of In-Place Oil Shale Resources of the Green River Formation, Piceance Basin, Western Colorado
Another area of possible resources are located in the Mancos Shale of the same area.