Feltville Formation

Feltville Formation
Stratigraphic range: Lower Jurassic

Exposure of Feltville Formation sandstone beneath a ledge of Preakness Basalt on Preakness Mountain in New Jersey.
Type Geological formation
Unit of Newark Supergroup
Underlies Preakness Basalt
Overlies Orange Mountain Basalt
Thickness maximum of 1,968 feet (600 m)[1]
Lithology
Primary Sandstone, Siltstone, Mudstone
Other Limestone
Location
Region Newark Basin of
Eastern North America Rift Basins
Extent continuous for ~40 miles (64 km) in New Jersey,
with outliers present in
New Jersey, New York
& Pennsylvania.
Type section
Named for Deserted Village of Feltville, New Jersey[1]
Named by Paul E. Olsen, 1980[1]

The Feltville Formation is a mapped bedrock unit primarily in New Jersey, with one known outlier in Pennsylvania and another one in New York. It is named for the Deserted Village of Feltville in Watchung Reservation, New Jersey, which is near where its type section was described by paleontologist Paul E. Olsen.[1]

Description

The Feltville Formation is composed of red, gray, and white Sandstone of varying grain thickness, as well as red, gray, and black siltstone and calcareous mudstone. Sandstone/siltstone layers tend to be alternatingly massive and cross-bedded. Black to white carbonaceous limestone layers exist near the base of the formation.[1][2] Additionally, pebbles and cobbles of quartz are embedded within layers of sandstone and siltstone that interfinger with the Feltville Formation near Oakland, New Jersey.[2]

Depositional Environment

The Feltville Formation can be characterized as a continuation of the Passaic Formation, which is mostly playa and alluvial fan deposits resulting from the rifting of Pangea. The primarily red color of this formation is often evidence that the sediments were deposited in arid conditions.[3] However, the Feltville Formation differs from the Passaic Formation in that it contains a more significant portion of non-red layers, which were laid down by deep lakes present during wetter periods.[4]

Fossils

Fish fossils, commonly those of the ray-finned Semionotus, can be found in limestone layers within the formation.[1] In other layers, indeterminate fossil ornithischian tracks have been noted,[5] along with additional reptile and dinosaur prints. Fossil plant remains, as well as root structures and pollen, are also found in the formation.[1]

Age

The Feltville Formation rests conformably above the Orange Mountain Basalt and below the Preakness Basalt, placing its deposition somewhere between approximately 199 and 196 million years ago during the early Jurassic stage known as the Hettangian.

Economic Uses

The Feltville Formation was once mined for freestone, as indicated by a historical work detailing quarrying operations at the base of Preakness Mountain in New Jersey.[6]

See also

References

In-line citations

  1. 1 2 3 4 5 6 7 Olsen, P.E., 1980. The Latest Triassic and Early Jurassic Formations of the Newark Basin (Eastern North America, Newark Supergroup): Stratigraphy, Structure, and Correlation. New Jersey Academy of Science Bulletin, v. 25, no. 2, p. 25-51.
  2. 1 2 Mineral Resources Online Spatial Data – Feltville Formation, New Jersey. U.S. Geological Survey. Accessed July 23, 2010.
  3. ↑ Faill, R.T., (2004). The Birdsboro Basin. Pennsylvania Geology V. 34 n. 4.
  4. ↑ Schlische, Roy W. Geology of the Newark Rift Basin. Department of Geological Sciences, Rutgers University, Piscataway, NJ. Accessed July 23, 2010.
  5. ↑ Weishampel, et al. (2004). "Dinosaur distribution." Pp. 517-607.
  6. ↑ Gordon, Thomas Francis. A Gazetteer of the State of New Jersey – Comprehending a General View of its Physical and Moral Condition, together with a Topographical and Statistical Account of its Counties, Towns, Villages, Canals, Railroads, &c. Published by D. Fenton, 1834. Available via Google Books

Additional references

  1. Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. ISBN 0-520-24209-2.
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