Pennsylvanian period
Học thuậtThân thiện
Definition
- Noun:
- A specific geological time period: The Pennsylvanian Period is a subdivision of the Carboniferous geological era, occurring approximately from 310 million to 280 million years ago. It is characterized by a warm climate and extensive swampy land environments.
Usage
- The term "Pennsylvanian Period" is used as a proper noun in geology and paleontology to refer to this specific interval of Earth's history. It is typically capitalized.
- It is used to describe the age of rock formations, fossil assemblages, and the environmental conditions prevalent at that time.
Examples
- Noun:
- Coal deposits from the Pennsylvanian Period are a major economic resource.
- Many early reptile fossils have been discovered in strata dating to the Pennsylvanian Period.
- The vast swamp forests of the Pennsylvanian Period eventually formed much of the world's coal.
Advanced Usage
- "the Pennsylvanian": Often used as a shortened form to refer to the Pennsylvanian Period.
- The rock formation is dated to the late Pennsylvanian.
- In formal geological timescales, it is preceded by the Mississippian Period and followed by the Permian Period.
Variants and Related Words
- Pennsylvanian (adj): Of or relating to the Pennsylvanian Period.
- Pennsylvanian strata are rich in plant fossils.
- Upper Carboniferous: A synonym used primarily in European geology, roughly equivalent to the Pennsylvanian Period.
Synonyms
- Late Carboniferous: A common synonym, especially in global geological contexts.
- Upper Carboniferous Period: As noted above.
Notes on Meaning
- The period is named after the U.S. state of Pennsylvania, where rocks from this age are extensively exposed and were first studied.
- It is distinct from the adjective "Pennsylvanian" used to describe a person or thing from the state of Pennsylvania. The geological term is always capitalized and typically includes "Period" for clarity.
Noun
- from 310 million to 280 million years ago; warm climate; swampy land