Eagle Ford Formation

Eagle Ford Formation
State Texas
Name Eagle Ford Formation
Geologic age Late Cretaceous
Lithologic constituents
Major
Sedimentary > Clastic > Siltstone (Bed)
Sedimentary > Clastic > Mudstone > Shale > Black-shale (Bed)
Incidental
Sedimentary > Carbonate > Limestone (Bed)
Comments In North, central, and south Texas including Quaternary for all of west Texas- Shale, siltstone, and limestone; upper part limest. and shale, ls lt-yellowish-brown, flaggy; lower part, siltst. and v. fine-grained sandst., lt-yellow to gray, laminated flaggy, some limestone, silty, med-brown, laminated, thickness 75-200 ft, thins NEward. In East Texas and Gulf Coast to Rio Grande- Shale and limestone. Upper part-- shale, compact, silty, contains fossil fish teeth and bones, 10 ft or more thick; middle part-- silty limest grading to calcar siltst, med gray weathers pale yellowish-brown, flaggy; lower part--shale, calcareous, dk gray, 7-50 ft thick. Thickness of Eagle Ford Formation 25-65 ft. In Texarkana Sheet (1966) thickness 60 ft feathers out east. In Sherman Sheet (1967) (NE Texas) shale, selenitic, bituminous, calcar concretions and septaria, thin platy beds of sandst. and sandy ls. in middle and upper part, med to dk gray; marine megafossils; thickness 300-400 ft.
References

Bureau of Economic Geology, 1977, Del Rio Sheet, Geologic Atlas of Texas, University of Texas, Bureau of Economic Geology, scale 1:250,000.

Bureau of Economic Geology, 1966, Texarkana Sheet, Geologic Atlas of Texas, University of Texas, Bureau of Economic Geology, scale 1:250,000.

Bureau of Economic Geology, 1967, Sherman 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.

NGMDB product
Counties Bell - Collin - Comal - Dallas - Denton - Edwards - Ellis - Fannin - Grayson - Hays - Hill - Johnson - Kinney - Lamar - McLennan - Medina - Red River - Tarrant - Uvalde - Val Verde - Williamson