Boquillas Formation

Boquillas Formation
Stratigraphic range: Cenomanian to Santonian
Boquillas Formation; Stratigraphic range: Cenomanian to Santonian
Type	Formation
Unit of	Eagle Ford Group / Terlingua Group
Sub-units	Ernst Member, San Vicente Member, Terrell Member, Lozier Canyon Member, Antonio Creek Member, Scott Ranch Member, Langtry Member [1]
Underlies	Austin Chalk or Aguja Formation
Overlies	Buda Limestone
Lithology
Primary	Marl
Other	Limestone, volcanic ash beds
Location
Region	West Texas
Country	United States
Type section
Named for	Boquillas post office, Big Bend National Park, Texas [2]
Named by	J. A. Udden [2]

Last updated March 15, 2019

The Boquillas Formation is a geologic formation deposited during the Late Cretaceous in modern-day West Texas. It is typically composed of alternating marls and limestones with thin volcanic ash beds (bentonites). It was named for outcrops near the former Boquillas post office in Big Bend National Park.^[2] The term Boquillas Formation has been used for rocks that outcrop from Del Rio, Texas to as far west as Doña Ana County, New Mexico.^[3]

The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series. The Cretaceous is named after the white limestone known as chalk which occurs widely in northern France and is seen in the white cliffs of south-eastern England, and which dates from this time.

West Texas is a loosely defined part of the U.S. state of Texas, generally encompassing the arid and semiarid lands west of a line drawn between the cities of Wichita Falls, Abilene, and Del Rio.

Marl or marlstone is a calcium carbonate or lime-rich mud or mudstone which contains variable amounts of clays and silt. The dominant carbonate mineral in most marls is calcite, but other carbonate minerals such as aragonite, dolomite, and siderite may be present. Marl was originally an old term loosely applied to a variety of materials, most of which occur as loose, earthy deposits consisting chiefly of an intimate mixture of clay and calcium carbonate, formed under freshwater conditions; specifically an earthy substance containing 35–65% clay and 65–35% carbonate. It also describes a habit of coralline red alga. The term is today often used to describe indurated marine deposits and lacustrine (lake) sediments which more accurately should be named 'marlstone'. Marlstone is an indurated rock of about the same composition as marl, more correctly called an earthy or impure argillaceous limestone. It has a blocky subconchoidal fracture, and is less fissile than shale. The term 'marl' is widely used in English-language geology, while the terms Mergel and Seekreide are used in European references.

Vertebrate fossils found in the Boquillas Formation include mosasaurs, fish bones, and shark's teeth.^[4]^[5] Invertebrate fossils found in the formation include ammonites, swimming crinoids, inoceramid clams, sea urchins, oysters, and foraminifera ^[1]

Vertebrates comprise all species of animals within the subphylum Vertebrata. Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 69,276 species described. Vertebrates include the jawless fishes and jawed vertebrates, which include the cartilaginous fishes and the bony fishes.

A fossil is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood, oil, coal, and DNA remnants. The totality of fossils is known as the fossil record.

Mosasaurs are an extinct group of large marine reptiles containing 38 genera in total. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. Mosasaurs probably evolved from an extinct group of aquatic lizards known as aigialosaurs in the Early Cretaceous. During the last 20 million years of the Cretaceous period, with the extinction of the ichthyosaurs and pliosaurs, mosasaurs became the dominant marine predators. They became extinct as a result of the K-Pg event at the end of the Cretaceous period, about 66 million years ago.

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The Woodbine Group is a geological formation in east Texas whose strata date back to the Early to Middle Cenomanian age of the Late Cretaceous. It is the producing formation of the giant East Texas Oil Field from which over 5.42 billion barrels of oil have been produced. The Woodbine overlies the Maness Shale, Buda Limestone, or older rocks, and underlies the Eagle Ford Group or Austin Chalk. In outcrop the Woodbine Group has been subdivided into the Lewisville Sandstone, Dexter Sandstone, and/or Pepper Shale formations. Thin-bedded sands of the Woodbine and Eagle Ford are collectively referred to as the "Eaglebine" oil and gas play in the southwestern portion of the East Texas region.

The Javelina Formation is a geological formation in Texas. Dating has shown that the strata date to the Maastrichtian stage of the Late Cretaceous, approximately 70 to 66.5 million years old. The middle part of the formation has been dated to about 69 million years ago plus or minus 1 Ma and the top situated near the Cretaceous–Paleogene boundary, dated to 66 Ma ago. Dinosaur remains are among the fossils that have been recovered from the formation.

The Black Peaks Formation is a geological formation in Texas whose strata date back to the Late Cretaceous. Dinosaur remains have been among the fossils reported from the formation. The boundary with the underlying Javelina Formation has been estimated at about 66.5 million years old. The formation preserves the rays Rhombodus and Dasyatis, as well as many gar scales.

The Lake Waco Formation is a geologic formation within the Eagle Ford Group deposited during the Middle Cenomanian to the Early Turonian of the Late Cretaceous in central Texas. The formation was named for outcrops near Lake Waco, south of the city of Waco, Texas by W. S. Adkins and F. E. Lozo in 1951. The Lake Waco Formation is primarily composed of shale, with minor amounts of limestone and volcanic ash beds (bentonites). It is subdivided into three members: Bluebonnet Member, Cloice Member, and the Bouldin Member. The Bluebonnet Member is 10 to 20 ft thick, and is made up of broken pieces (prisms) of inoceramid clams and planktonic foraminifera. The Cloice Member is 35 ft thick at its type section on the Cloice Branch of the South Bosque River, whereas the Bouldin Member was named for outcrops on Bouldin Creek south of downtown Austin, where it is roughly 9 ft thick. They are both made up of shales rich in organic matter with thin limestones and volcanic ash beds.

The Ogallala Formation is a Miocene to Pliocene geologic unit in the High Plains of the western United States and the location of the Ogallala Aquifer.. Notably, it records the North American Land Mammal Ages (NALMAs) Hemphillian, Clarendonian, and Barstovian. The Ogallala Formation outcrops of Lake Meredith National Recreation Area preserve fish fossils. Similar specimens from the same formation are found at Alibates Flint Quarries National Monument in Texas.

The Hannold Hill Formation is an Eocene geologic unit in the western United States. It preserves the fossilized remains of the ray Myliobatis and gar.

The Pen Formation is a Campanian-age geologic unit in the western United States.

The Doughnut Formation is an Upper Mississippian geologic unit in the western United States. Fish fossils have been discovered shale outcrops of this formation in Dinosaur National Monument.

The Cabrillo Formation is a Maastrichtian stage geologic formation in coastal San Diego County, southern California. It is part of the Rosario Group.

The Cliff House Formation is a late Campanian stratigraphic unit in the western United States. Outcrops of the formation in Mesa Verde National Park have produced fossil shark teeth along with the jaws, teeth and fins of Enchodus.

The Glenns Ferry Formation is a Pliocene stratigraphic unit in the western United States. Outcrops of the formation in Hagerman Fossil Beds National Monument preserve the remains of seven fish species, five of which are extinct. These include the teleosteans Mylopharodon hagermanensis, Sigmopharyngodon idahoensis, and Ptychocheilus oregonensis, Ameirurus vespertinus, and the sunfish Archoplites taylori. A nearly complete skull of the catfish Ameirurus vespertinus was recovered in 2001 from the wall of the Smithsonian Horse Quarry.

The Lost Burro Formation is a Middle to Upper/Late Devonian geologic formation in the Mojave Desert of California, in the Western United States.

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The Fernando Formation is a Plio-Pleistocene marine mudstone, siltstone and sandstone formation in the greater Los Angeles Basin, Ventura Basin, and Santa Monica Mountains, in Los Angeles County of Southern California.

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The Arcadia Park Shale is a geologic formation within the Eagle Ford Group that outcrops in the northern portion of East Texas. It was deposited during the Middle to Late Turonian of the Late Cretaceous. It was originally described by W. L. Moreman from outcrops near the former Arcadia Park railway station west of downtown Dallas, where it is 100 ft thick. In the type area there is an unconformity between the Arcadia Park and the underlying Britton Formation. The base of the Arcadia Park is a thin limestone termed the Kamp Ranch Limestone. The Kamp Ranch Limestone is made up of broken pieces (prisms) of Inoceramus clams, and also contains shark's teeth. The remainder of the Arcadia Park in the Dallas area is shale with concretions. Sandstones are found within the Arcadia Park north of Dallas. The sandstones have been termed the Bells Sandstone Member for outcrops in Grayson County, and the Sub-Clarksville Sandstone in the subsurface. The shale overlying the Bells Sandstone has been named the Maribel Shale

The Eagle Ford Group is a sedimentary rock formation deposited during the Cenomanian and Turonian ages of the Late Cretaceous over much of the modern-day state of Texas. The Eagle Ford is predominantly composed of organic matter-rich fossiliferous marine shales and marls with interbedded thin limestones. It derives its name from outcrops on the banks of the West Fork of the Trinity River near the old community of Eagle Ford, which is now a neighborhood within the city of Dallas. The Eagle Ford outcrop belt trends from the Oklahoma/Texas border southward to San Antonio, westward to the Rio Grande, Big Bend National Park, and the Quitman Mountains of West Texas. It also occurs in the subsurface of East Texas and South Texas, where it is the source rock for oil found in the Woodbine, Austin Chalk, and the Buda Limestone, and is produced unconventionally in South Texas and the "Eaglebine" play of East Texas. The Eagle Ford was one of the most actively drilled targets for unconventional oil and gas in the United States in 2010, but its output had dropped sharply by 2015. By the summer of 2016, Eagle Ford spending had dropped by two thirds from $30 billion in 2014 to $10 billion, according to an analysis from the research firm, Wood Mackenzie. This strike has been the hardest hit of any oil fields in the world. The spending is, however, expected to increase to $11.6 billion in 2017. A full recovery is not expected any time soon.

Ochopristis is a genus of Late Cretaceous cartilaginous fish whose fossils have been found in the Aguja and Pen Formations of Big Bend National Park, Texas, USA.

Squatirhina is a genus of Late Cretaceous cartilaginous fish whose fossils have been found in the Aguja and Pen Formations of Big Bend National Park, Texas, USA.

ReBecca Hunt-Foster is an American paleontologist. She has worked with dinosaur remains from the Late Jurassic to Late Cretaceous of the Colorado Plateau, Rocky Mountains, Southcentral, and the Southwestern United States of America. She described the dinosaur Arkansaurus fridayi and identified the first juvenile Torosaurus occurrences from Big Bend National Park in North America in 2008.

References

1 2 Denne, R. A., Breyer, J. A., Callender, A. D., Hinote, R. E., Kariminia, M., Kosanke, T. H., Kita, Z., Lees, J. A., Rowe, H., Spaw, J. M., and Tur, N. (2016). Biostratigraphic and geochemical constraints on the stratigraphy and depositional environments of the Eagle Ford and Woodbine Groups of Texas: in Breyer, J. A. (ed.), The Eagle Ford Shale: A renaissance in U.S. oil production, AAPG Memoir 110, p. 1-86.
1 2 3 Udden, J. A., 1907, A sketch of the geology of the Chisos country, Brewster County, Texas: University of Texas Bulletin 93, 101 p.
↑ Lovejoy, E.M.P., 1976, Geology of Cerro de Cristo Rey uplift, Chihuahua and New Mexico: New Mexico Bureau of Mines and Mineral Resources Memoir, no. 31.
↑ Gorden L. Bell, Jr., Kenneth R. Barnes and Michael J. Polcyn (2013) Late Cretaceous mosasauroids (Reptilia, Squamata) of the BigBend region in Texas, USA. Earth and Environmental Science Transactions of the Royal Society of Edinburgh, Available onCJO 2013 doi:10.1017/S1755691013000406
↑ Hunt, ReBecca K., Vincent L. Santucci and Jason Kenworthy (2006) A preliminary inventory of fossil fish from National Park Service units, in S.G. Lucas, J.A. Spielmann, P.M. Hester, J.P. Kenworthy, and V.L. Santucci (eds.), Fossils from Federal Lands. New Mexico Museum of Natural History and Science Bulletin 34, p. 63–69.

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[Denne_et_al.-1] 1 2 Denne, R. A., Breyer, J. A., Callender, A. D., Hinote, R. E., Kariminia, M., Kosanke, T. H., Kita, Z., Lees, J. A., Rowe, H., Spaw, J. M., and Tur, N. (2016). Biostratigraphic and geochemical constraints on the stratigraphy and depositional environments of the Eagle Ford and Woodbine Groups of Texas: in Breyer, J. A. (ed.), The Eagle Ford Shale: A renaissance in U.S. oil production, AAPG Memoir 110, p. 1-86.

[Udden-2] 1 2 3 Udden, J. A., 1907, A sketch of the geology of the Chisos country, Brewster County, Texas: University of Texas Bulletin 93, 101 p.

[3] Lovejoy, E.M.P., 1976, Geology of Cerro de Cristo Rey uplift, Chihuahua and New Mexico: New Mexico Bureau of Mines and Mineral Resources Memoir, no. 31.

[4] Gorden L. Bell, Jr., Kenneth R. Barnes and Michael J. Polcyn (2013) Late Cretaceous mosasauroids (Reptilia, Squamata) of the BigBend region in Texas, USA. Earth and Environmental Science Transactions of the Royal Society of Edinburgh, Available onCJO 2013 doi:10.1017/S1755691013000406

[nps-fish-bigbend-65-5] Hunt, ReBecca K., Vincent L. Santucci and Jason Kenworthy (2006) A preliminary inventory of fossil fish from National Park Service units, in S.G. Lucas, J.A. Spielmann, P.M. Hester, J.P. Kenworthy, and V.L. Santucci (eds.), Fossils from Federal Lands. New Mexico Museum of Natural History and Science Bulletin 34, p. 63–69.