Catskill Delta
Encyclopedia
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 10,000 feet). 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 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.
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.
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
Catskill Formation or the Catskill clastic wedge is a unit of mostly terrestrial sedimentary rock found in Pennsylvania
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...
and New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...
. Minor marine layers exist in this thick rock unit (up to 10,000 feet). It is equivalent to the Hampshire Formation of Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
, West Virginia
West Virginia
West Virginia is a state in the Appalachian and Southeastern regions of the United States, bordered by Virginia to the southeast, Kentucky to the southwest, Ohio to the northwest, Pennsylvania to the northeast and Maryland to the east...
, and Virginia
Virginia
The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
.
The Catskill is the largest bedrock unit of the Upper Devonian in northeast Pennsylvania and the Catskill region
Catskill Mountains
The Catskill Mountains, an area in New York State northwest of New York City and southwest of Albany, are a mature dissected plateau, an uplifted region that was subsequently eroded into sharp relief. They are an eastward continuation, and the highest representation, of the Allegheny Plateau...
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 predominantly red sandstone
Red sandstone
Red sandstone may refer to:*Sandstone appearing red due to the inclusion of iron oxides *Old Red Sandstone*New Red Sandstone*Ardjachie Stone*Aizkorri , Basque Mountains massif...
indicating a large scale terrestrial deposition during the Acadian orogeny
Acadian orogeny
The Taconic, Acadian and Alleghenian orogenies are the three tectonic phases responsible for the formation of the present Appalachian Mountains. The Acadian orogeny is a middle Paleozoic mountain building episode dating back 325-400 million years which should not be regarded as a single event but...
. Many beds are cyclical in nature, preserving the record of a dynamic environment during its approximately 20 million years of deposition.
Depositional Environment
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 AmericaNorth America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
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
Catskill Mountains
The Catskill Mountains, an area in New York State northwest of New York City and southwest of Albany, are a mature dissected plateau, an uplifted region that was subsequently eroded into sharp relief. They are an eastward continuation, and the highest representation, of the Allegheny Plateau...
and Appalachian Mountains
Appalachian Mountains
The Appalachian Mountains #Whether the stressed vowel is or ,#Whether the "ch" is pronounced as a fricative or an affricate , and#Whether the final vowel is the monophthong or the diphthong .), often called the Appalachians, are a system of mountains in eastern North America. The Appalachians...
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
Petroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...
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
Old Red Sandstone
The Old Red Sandstone is a British rock formation of considerable importance to early paleontology. For convenience the short version of the term, 'ORS' is often used in literature on the subject.-Sedimentology:...
, 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.