Sublett basin

The Phosphoria Formation was deposited in a foreland basin between the Continental margin and the North American cratonic shelf. This foreland basin, which is here defined by the area of deposition of the two organic-ncarbon-rich mudstone members of the Phosphoria (fig. 1), has been named the Sublett basin (8)5 and it covers an extensive area of approximately 400,000 knr (about 700 km by 600 km). The basin has a northwest-southeast-trending axis and seems to have been deepest in central Idaho where deep-water sedimentary rocks equivalent to the Phosphoria Formation are exceptionally thick. The depth decreased toward the shelves and land areas indicated in figure 1. The deepest part of the Sublett... 

Figure 1. Sublett basin (solid line, dashed where uncertain) in relation to major Permian structural and paleogeographic elements. Areal extent of Meade Peak indicated by left diagonal rules Retort, by right diagonal rules limit of middle Permian epicontinental shelf deposits indicated by dotted line. Cross-section A-A shown in Figure 3, B-B in Figure 2.

The southwest limit of the Sublett basin in Nevada was along the Humboldt highland (17). The Humboldt highland was the principal source of terrigenous sediments incorporated in the Murdock Mountain Formation (18), which is equivalent to the lower part of the Phosphoria Formation (fig. 2). 

Figure 3. Cross-section A-A showing generalizedfacies relations and nomenclature of middle Permian strata across Sublett basin from Cassia Mountains, Idaho to central Wyoming. (Section location shown in...

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