The Tully Formation is a geologic unit in the Appalachian Basin. The Tully was deposited as a carbonate rich mud, in a shallow sea at the end of the Middle Devonian.[1] Outcrops for the Tully are found in New York State and Pennsylvania.[2] It is also found subsurface in western Maryland and northern West Virginia. A number of fossil remains from marine organisms maybe found in Tully out crops.
| Tully Formation | |
|---|---|
| Stratigraphic range: Devonian | |
 Tully Formation at Taughannock Falls State Park | |
| Type | Formation |
| Sub-units |
|
| Underlies | Harrell Shale/Genesee Group |
| Overlies | Hamilton Group |
| Lithology | |
| Primary | Limestone |
| Other | Shale, Siltstone, and Sandstone |
| Location | |
| Region |  Maryland New York Pennsylvania West Virginia |
| Country | United States Canada |
| Type section | |
| Named for | Tully, NY |
| Named by | Vanuxem (1839) |
Description
editThe Tully is primary made up of limestone. There there are also layers with much higher clay contend resulting in a calcareous shale. To the east the Tully becomes siliciclastic. This is due to sediments being washed in from the Acadian Mountains to the east. By the time the Tully was being deposited the Appalachian Basin had been nearly filled in that the Tully was deposited on a broad planform of rock.[3] The Tully ranges in thickness to less than 1' in western New York to 70'+ thick in central Pennsylvania and 90'+ thick in southwestern Pennsylvania and northern West Virginia.
Fossils
editBrachiopods
editTullypothyridina, Camarotoechia Mesocostale, Rhyssochonetes, Emanuella, Pseudoatrypa, Spinatrypa, Tylothyris, Mucrospirifer tulliensis, Cyrtina, Tullypothyridina, Echinocoelia, Strophodonta
References
edit- ^ Philip H. Heckel (1963). "Depositional Environment of the Devonian Tully Limestone of Central New York: ABSTRACT". AAPG Bulletin. 47. doi:10.1306/bc7439df-16be-11d7-8645000102c1865d. ISSN 0149-1423.
- ^ Stevenson, R. E; Skinner, W. S. (1949). "The Tully Clastics of New York and Pennsylvania". Pennsylvania Academy of Science. 23: 28–33. JSTOR 44109398.
- ^ Baird, G.C.; Zambito, J.J.; Brett, C.E. (2012). "Genesis of unusual lithologies associated with the Late Middle Devonian Taghanic biocrisis in the type Taghanic succession of New York State and Pennsylvania". Palaeogeography, Palaeoclimatology, Palaeoecology. 367–368: 121–136. Bibcode:2012PPP...367..121B. doi:10.1016/j.palaeo.2011.11.010. ISSN 0031-0182.
