|Name||Jasper Creek Formation|
|Geologic age||Late Pennsylvanian; Missouri Series|
Sedimentary > Clastic > Mixed-clastic > Sandstone-mudstone (Bed)
|Comments||Mapped in eastern Jack and western Wise Counties (Fort Worth syncline). On Geol. Map of Texas (1992) unit has formation status. On Sherman Sheet (1967) unit is Jasper Crk Shale Mbr of Graford Fm. On Wichita Falls-Lawton Sheet (1987) mapped as a formation in the Canyon Group. The latter apparently is the correct, preferred usage. Upper part--mudstone and sandstone; mudst. 2-95 ft thick, bedding thick to massive, med. gray, weathers lt.olive gray and moderate yell-brn; Ss units fr. few inches to about 10 ft thick, v. fine to med. grained, poor to well sorted, in part calcite cemented, some limonite cement, ironst. concretions, beds thin to thick, flaggy, even to irreg., sed. structures: crossbedding, ripple marks, flute casts, and convolute (soft sedi. deformed) beds; local fine-grained chennel-fill bodies; pale yell-org, pale greenish-yell. pale brn. Middle part--clayst. and mudst., units to 105 ft thick, beds thick to massive, yell-gray to lt olive-gray. Lower part--mudst. and sandst. mudst mod yell-brn, reddish-gray, v. pale grn, grayish-red. Other character of mudst./sandst. similar to upper part. Fossils in mudst--finely comminuted plant debris throughout, in upper part a few crinoid columnals, in middle part small mollusks, ostracods, and fish teeth, in lower part plant fossils and burrows. Abv. thick sandst unit--reworked shell debris and abundant Lebensspurren; in sandst--plant fossils common in lower part. Thickness of IPjc unit 290+-ft in (reported as about 90 ft in Wichita Falls-Lawton Sheet)|
|Stratigraphic units||Graford Formation, Canyon Group|
Bureau of Economic Geology, 1987, Wichita Falls-Lawton Sheet, Geologic Atlas of Texas: University of Texas at Austin, Bureau of Economic Geology, scale 1:250,000.
Bureau of Economic Geology, 1992, Geologic Map of Texas: University of Texas at Austin, Virgil E. Barnes, project supervisor, Hartmann, B.M. and Scranton, D.F., cartography, scale 1:500,000.
|Counties||Jack - Wise|