Lecture 12: Late Paleozoic Geology

This flashcard set explores the late Paleozoic era, highlighting key events such as major orogenies (mountain-building events) and geological sequences. It covers the formation of supercontinents, significant tectonic activity, and changes in Earth's climate and life forms during this pivotal period.

Carboniferous Period

Dominated by coal; subdivided into Mississippian and Pennsylvanian; characterized by coal-bearing layers and limestone deposits.

Thrust faults

A type of reverse fault where one side of the fault is pushed up and over the other side, usually at a shallow angle or gentle slope. It's like pushing one layer of rock over another.

Unconformity

A surface in the rock record that represents a period of erosion or non-deposition, indicating a gap in the geological history; types are angular, disconformity, and nonconformity.

Lignite

Lowest grade of coal, also known as brown coal; burns with a lower energy output and is less efficient than higher-grade coals like bituminous or anthracite.

Marcellus/Chattanooga Shale

Deeply buried shale; one of the largest known reservoirs of natural gas.

Oriskany Sandstone

Initial deposit of the Kaskaskia sequence as sea level begins to rise; consists of very mature and clean quartz sands that eroded from Taconic mountains.

Pangea

Final well-known supercontinent that existed during the late Paleozoic and early Mesozoic eras, uniting most of Earth's landmasses into one large, continuous landmass.

Peat

A type of soil made up of partially decayed plant material that accumulates in wet, swampy areas; lowest grade of coal we can access.

Permian Basin

Restricted basin that alternates between organic rich mudstone deposits and halite deposits that will ultimately aid in trapping oil.

Sonoma Orogeny

Another orogeny occurring on west coast at the end of the Permian into the Triassic; collision of an eastward-moving island arc.

Dimension stone

Granitic intrusions; a resource for decorative rock.

Foreland basin

Form when lithosphere flexes downward in front of mountain belt in response to added load of thickened crust that results from collision of two plates; like a bowl.

Hercynian Orogeny

During Silurian-Devonian-Carboniferous in central Europe; caused by collision of Northern Africa with Europe.

Hydraulic fracturing (fracking/hydrofracking)

A method used to extract oil or natural gas from deep underground.

Catskill Wedge

Eroded material carried west by streams to form this massive sedimentary deposit.

Coal

A black or brownish high grade rock that can be burned to produce energy; forms from the remains of ancient plants that were buried and compressed over millions of years.

Anthracite

The highest grade of coal, known for its high carbon content, high energy output, and clean-burning properties, making it the most efficient and valuable type of coal for heating.

Antler Orogeny

First orogeny in the west coast during Late Devonian through Mississippian-Pennsylvanian, island arc accretion western margin of North America; the convergence was accompanied by massive thrust-faulting.

Bituminous

A type of coal that is more compressed and has a higher energy content than lignite, making it suitable for generating electricity and in industrial processes like steelmaking.

Alamo Impact / Alamo Breccia

Possible meteorite impact during Late Devonian, but crater is not visible due to mountain building; a thick bed of carbonate breccia has been found throughout the state.

Absaroka Sequence

Marked by significant sea level changes that created alternating layers of marine and non-marine sediments, resulting in extensive rock formations like coal beds, sandstones, and shales in North America.

Late Paleozoic Geologic Events

Sedimentary strata formed in "packages" due to rising and falling seas; unconformities with falling seas; mountain building events like Acadian, Alleghenian, Antler, and Hercynian orogenies.

Kaskaskia Sequence

Initial deposit of the Carboniferous; characterized by Oriskany Sandstone and Marcellus/Chattanooga Shale; marked by sea level rise and anoxic conditions.

Cyclothems

Cyclic repetition of marine and non-marine strata; reflect sea level changes; common in Pennsylvanian; contain coal beds and fossils; result from step-wise advances and retreats of seas.

Coal Formation

Peat accumulation and compaction into coal; peat is the lowest grade; higher grades with time, pressure, and heat; types include brown coal, black coal, and bituminous coal.

Permian Sediments

Kaibab Limestone formation; Phosphoria Formation as a phosphorus resource; deposition in the Great Permian Basin; major oil-producing region.

Acadian Orogeny

Collision of Avalon terrane with N. American craton; formation of Acadian mountain belt; granitic intrusions; Catskill Wedge; Marcellus Shale as a natural gas reservoir.

Alleghenian Orogeny

Collision of Gondwana with N. America; formation of Appalachian Mountains; extensive thrust faulting, uplift, and metamorphism; connection of North America with northwestern Africa.

Caledonian Orogeny

Mountain building in western Europe; continental collision between Northern Africa and Europe; formation of Northern Appalachian Mountains; similar to Acadian Orogeny.

Cordillera

Western system of mountain ranges in N. America; from Rocky Mountains to Pacific Coast; formed by Antler Orogeny and Sonoma Orogeny; includes Rockies, Sierra Nevada's, and Coast Ranges.

Cordilleran Mountain Range

A mountain range that began forming due to tectonic forces and volcanic activity.

Sedimentary rocks

Rocks formed by the deposition and solidification of sediment, including sandstones, shales, and limestones.

Sedimentary basins

Large basins that developed as a result of tectonic activity and sediment deposition, such as the Great Basin.