Catskill Formation
{{Short description|Unit of sedimentary rock in the US}}
{{more citations needed|date=April 2014}}
{{Infobox rockunit
| name = Catskill Formation
| image = Catskill1.jpg
| caption = Outcrop of the Irish Valley Member of the Catskill Formation along the Horseshoe Curve, Blair County, Pennsylvania
| type = sedimentary
| age = {{fossil range|365.2|358.8|Late Devonian (Late Famennian)}}
| period = Devonian
| prilithology = Sandstone
| otherlithology = Siltstone, shale
| namedfor = Catskill Mountains, New York
| namedby =
| region = Appalachian Mountains
| country = United States
| coordinates =
| unitof =
| subunits =
| underlies = Rockwell Formation, Huntley Mountain Formation, Pocono Formation, Spechty Kopf Formation
| overlies = Foreknobs Formation, Lock Haven Formation, Trimmers Rock Formation
| thickness = Up to {{convert|10000|ft|m|abbr=on}}
| extent = Pennsylvania, New York (state)
| area =
| map =
| map_caption =
}}
The Devonian Catskill Formation or the Catskill Clastic Wedge is a unit of mostly terrestrial sedimentary rock found in Pennsylvania and New York. Minor marine layers exist in this thick rock unit (up to {{convert|10000|ft|m}}). It is equivalent to the Hampshire Formation of Maryland, West Virginia, and Virginia.
The Catskill is the largest bedrock unit of the Upper Devonian in northeast Pennsylvania and the Catskill region of New York, from which its name is derived. The Pocono Mountains of Pennsylvania are largely underlain by this unit as well. The rocks of the Catskill are a clastic wedge of predominantly red sandstone, indicating a large-scale terrestrial deposition during the Acadian orogeny. Many beds are cyclical in nature, preserving the record of a dynamic environment during its approximately 20 million years of deposition.
The Catskill Formation preserves a highly diverse paleobiota, including many early sarcopterygians (especially tetrapodomorphs), providing important evidence about the evolution of terrestrial vertebrates. The formation also provides important fossils about the evolution of land plants.{{Cite journal |last=Broussard |first=David R. |last2=Trop |first2=Jeffrey M. |last3=Benowitz |first3=Jeff A. |last4=Daeschler |first4=Edward B. |last5=Chamberlain |first5=John A. |last6=Chamberlain |first6=Rebecca B. |date=2018-12-15 |title=Depositional setting, taphonomy and geochronology of new fossil sites in the Catskill Formation (Upper Devonian) of north-central Pennsylvania, USA, including a new early tetrapod fossil |url=https://linkinghub.elsevier.com/retrieve/pii/S0031018218303274 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |volume=511 |pages=168–187 |doi=10.1016/j.palaeo.2018.07.033 |issn=0031-0182}}
Geology
= Depositional environment =
File:Catskill-slab-new.jpg of the Endless Mountain Stone Company, Susquehanna County, Pennsylvania, showing mud clasts within sandstone]]
File:Meandering catskill MCR1.JPG
During the Devonian period, the Catskill Delta was formed by a series of river deltas and otherwise marshy terrain. This terrain was sandwiched between the epicontinental Kaskaskia Sea in central North America and the now-vanished Acadian Mountains. Erosion brought sediment from the mountain westwards into the sea, forming the deltas.
Eventually, the Delta formation was buried and transformed into sandstone, which was then revealed in places when the Catskill and Appalachian Mountains were formed at a later date. This transformation and uncovering is the primary reason why the Catskill Delta is notable in the present. Western Pennsylvania's petroleum was formed as a consequence. This was the first major oil region to be developed.
The Catskill was once considered to be related to the Old Red Sandstone, but in actuality, the two are only coincidentally similar. Both formed at approximately the same time, and under similar conditions: to the north of the Acadian Mountains were the Caledonian Mountains, and a similar region of marsh and river delta formed there.
= Glacial erosion =
Though both mountain ranges were formed during the Acadian orogeny, the Catskill Mountains, unlike the Appalachian Mountains underwent glacial erosion.{{Cite journal|last=Rich|first=John Lyon|date=1906|title=Local Glaciation in the Catskill Mountains|journal=The Journal of Geology|volume=14|issue=2|pages=113–121|jstor=30055593|doi=10.1086/621285|bibcode=1906JG.....14..113R |s2cid=129029014 }} Much of what formed the Catskills as they stand today is a result of the Wisconsin glaciation which ended only about 12,000 years ago.{{Cite book|title=The Catskills in the Ice Age|last=Titus|first=Robert|publisher=Purple Mountain Press|year=1996|isbn=978-0-935796-77-3|location=Flieschmanns, New York|pages=14–29}}
There are many signs of the Glacial period event which carved the current day Catskill Mountains.
These markers include:
- Glacial Erratics such as the Devils Tombstone
- Striations
- "Dance Floors" such as Pratt Rock
- Terminal moraines
= Members =
== Eastern Pennsylvania ==
Towamensing, Walcksville, Beaverdam Run, Long Run, Packerton, Poplar Gap, Sawmill Run, Berry Run, Clarks Ferry, and Duncannon.
== Central Pennsylvania ==
Irish Valley, Sherman Creek, Buddys Run, Clarks Ferry, and Duncannon.
{{Wide image|Geologic cross section of Devonian strata from New York to Alabama.svg|1000px|Geologic cross section of upper to middle Devonian strata from Cherry Valley, New York, south-southwest across the Allegheny Plateau and then along the Ridge-and-Valley Appalachians to Tennessee. The Catskill Formation is at the top.{{cite journal
|author1=Boughton, Carol J. |author2=McCoy, Kurt J. | publisher = U.S. Geological Survey
| year = 2006
| title = Hydrogeology, Aquifer Geochemistry, and Ground-Water Quality in Morgan County, West Virginia
| url = http://pubs.usgs.gov/sir/2006/5198/
| id= Scientific Investigations Report 2006-5198
}}|100%|left}}
{{clear}}
Paleobiota
= Placoderms =
= Acanthodians =
class="wikitable" align="center"
! colspan="6" align="center" |Acanthodians of the Catskill Formation |
Genus
!Species !Presence !Material !Notes !Images |
---|
Gyracanthus
| | |A gyracanthid. |
= Chondrichthyans =
class="wikitable" align="center"
! colspan="6" align="center" |Chondrichthyans of the Catskill Formation |
Genus
!Species !Presence !Material !Notes !Images |
---|
Ageleodus
|A. pectinatus | |Teeth |A holocephalan of uncertain affinities. |
Ctenacanthus
|C. sp. | | |
= Actinopterygians =
class="wikitable" align="center"
! colspan="6" align="center" |Actinopterygians of the Catskill Formation |
Genus
!Species !Presence !Material !Notes !Images |
---|
Limnomis
|L. delaneyi | | |An early ray-finned fish.{{Cite journal |last=Daeschler |first=Edward B. |date=2000 |title=An Early Actinopterygian Fish from the Catskill Formation (Late Devonian, Famennian) in Pennsylvania, U.S.A. |url=https://www.jstor.org/stable/4065069 |journal=Proceedings of the Academy of Natural Sciences of Philadelphia |volume=150 |pages=181–192 |issn=0097-3157}} | |
= Sarcopterygians =
References
{{Reflist}}
External links
- [http://csmres.jmu.edu/geollab/vageol/vahist/catskilenv.html Depositional environments in the Catskill Clastic Wedge]
- [http://www.devoniantimes.org/index.html Devonian Times] Website summarize about Red Hill Shale in Catskill Formation
{{Chronostratigraphy of Pennsylvania}}
{{Portal bar|Devonian}}
Category:Geologic formations of New York (state)
Category:Geologic formations of Pennsylvania
Category:Devonian Pennsylvania
Category:Devonian System of North America
Category:Devonian geology of Pennsylvania
Category:Devonian geology of New York (state)
Category:Devonian southern paleotemperate deposits
Category:Sandstone formations of the United States