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THE CARBONIFEROUS

 (Mississippian, Pennsylvanian)

      354 to 290 Million Years Ago

 

Introduction

-         The Carboniferous, known as the Age of Plants, makes up about 1.6 percent of geologic time.

 

-         The Period is divided into the sub-periods of the Mississippian (Lower Carboniferous) and Pennsylvanian (Upper Carboniferous). It took place 354 million years ago and ended around 290 million years ago, totaling 64 million years,

 

-          The Mississippian takes place from about 354 to 323 mya, and the Pennsylvanian from about 323 to 290 mya. The periods beginning and end is uncertain by 5 to 10 million years. The period is defined by massive plants and insects that occupied the northern hemisphere while giant glaciers oscillated in the southern hemisphere, drastically affecting all aspects of life on earth.

 

-          The unique system that divides the period was developed in order to separate the coal-rich layers of the Pennsylvanian and the limestone deposits of the Mississippian. Thus explaining the differences of stratigraphy on each continent.

 

 

Climate

-          The beginning of the Carboniferous generally had a more uniform, tropical, and humid climate throughout the year. Seasons, if any, were indistinct.

 

-          These observations are based on comparing the morphology of the plants that exist in the fossil record with plants that are present today. The morphology of the Carboniferous plants resembles the plants that live in tropical and mildly temperate areas today. Many of them lack growth rings, suggesting a uniform climate.

 

-          This uniformity in climate may have been the result of the large expanse of ocean that covered the entire surface of the globe except for a small, localized section where Pangea, the massive super continent that existed during the late Paleozoic and early Triassic, was forming during the Carboniferous.

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Sea Conditions

-          Shallow, warm, marine waters often flooded the continents.

 

-          Attached filter feeders such as bryozoans, particularly fenestellids, were abundant in this environment, and the sea floor was dominated by brachiopods. Trilobites were increasingly scarce while foraminifers were abundant. The heavily armored fish from the Devonian became extinct, being replaced with fish fauna that look more modern.

Brachiopod

 

http://upload.wikimedia.org/wikipedia/commons/4/45/Brachiopod_Neospirifer.jpg

-          Near the end of the Mississippian, uplift and erosion of the continents occurred, causing an increase in the number of floodplains and deltas present.

 

-          Freshwater clams first appear along with an increase in gastropod, bony fish, and shark diversity. At first glance, it may seem that the marine habitat has grown allowing the diversity of marine life to increase, but in actuality, the movement of the continents to form one large continental mass decreased the sea coast.

Gastropod

 

http://www.fossiliferous.co.uk/MS%20176.jpg

-          The amount of space available for marine life declined, and the sea levels all over the world fluctuated because of the presence of two large ice sheets at the southern pole.

 

-          Because so much water is taken out of the water cycle, the sea levels drop, leading to the mass extinction of shallow marine invertebrates, the gradual decline of swamps, and the increase in terrestrial habitat.

 

-          These effects are reversed when the glaciers start to recede, releasing the water that they had stored as ice back into the oceans, flooding the swamps and the floodplains again.

 

-          Carboniferous rock formations often occur in patterns of stripes with shale and coal seams alternating, indicating the cyclic flooding and drying of an area.

 

Habitat Shift

-          The uplift of the continents caused a transition to a more terrestrial environment during the Pennsylvanian period.

 

-          Swamp forests as well as terrestrial habitats became common and widespread. In the swamp forests, the vegetation was marked by the numerous different groups that were present.

-          Vegetation included giant club mosses, tree ferns, great horsetails, and towering trees with strap-shaped leaves. Over millions of years, the organic deposits of this plant debris formed the world's first extensive coal deposits—coal that humans are still burning today.

 

-          The growth of these forests removed huge amounts of carbon dioxide from the atmosphere, leading to a surplus of oxygen. Atmospheric oxygen levels peaked around 35 percent, compared with 21 percent today.

 

 

 

 

 

 

Outer surface of a Lepidophloios stem, an arborescent lycophyte showing the typical leaf scars. Coal ball from the Pennsylvanian (Upper Carboniferous) of North America.

 

http://www.uni-muenster.de/GeoPalaeontologie/Palaeo/Palbot/ewald1.htm

 

Terrestrial Life

-          This abundance of oxygen sparked an exponential increase in the size of vascular plants. It also may explain the giant insects that emerged—the size reached by insects and similar creatures is thought to be limited by the amount of air they are able to breathe.

 

-          Deadly poisonous centipedes some six feet (two meters) in length crawled in the company of mammoth cockroaches and scorpions as much as three feet (one meter) long. Most impressive of all were dragonflies that grew to the size of seagulls.

 

-          Land animals included primitive amphibians, reptiles (which first appeared in the Upper Carboniferous), spiders, millipedes, land snails, scorpions, enormous dragonflies, and more than 800 kinds of cockroaches.

-          Tetrapods (shown above) gained prominence when new species laid amniote eggs, the first of their kind to have shells, protecting the unborn and enabling the Tetrapoda to dwell on land. These first walking vertebrates were mostly amphibians and reptiles. They only made up a minor percentage of the population of earth.

 

-          Lycopsids, seedless plants, played a vital role in the environment and were a primary source of carbon that produced the coal beds of this period. Some grew to a height of 35 meters and formed large forests. Present in few numbers today, they are the oldest vascular plants on earth.

 

-          A group of sharks, the Cestraciontes—or shell-crushers—were dominant among the larger marine animals.

 

-          Near the end of the Mississippian, uplift and erosion of the land masses created new deltas and floodplains which supported less corals, crinoids, blastoids, cryozoans, and bryzoans, species that had previously been present in large quantities.

 

-          Ferns and sphenopsids became more important later during the Carboniferous, and the earliest relatives of the conifers appeared.

 (Conifer)

http://www.ucmp.berkeley.edu/seedplants/conifers/images/lebachia.jpg

 

Orogenies

The United States during the Pennsylvanian about 300 mya. The western states are under a deep ocean while the center of North America comprises a shallow sea. Swamp areas stretch as far south as central Texas and as far north as New York. On the west coast are the ancestral formations of the Sierra Nevada, then in the Midwest are the Rocky, Ozark, and Ouachita mountains, and on the east the Appalachians. These highlands supplied much of the sediment deposits in present-day North America.

 

- Three major orogenies occurred during the Carboniferous:

1)      Laurussia (Today’s Europe and North America) collided into Gondwanaland, producing the Appalachian mountain belt in eastern North America and

2)      The Hercynian Mountains in the UK.

3)       A later collision between Siberia and Eastern Europe created the Ural Mountains in western Russia.

 

Plate Tectonics

-         The Carboniferous is the beginning period of which the super continent Pangaea began forming. Gondwanaland shifted towards the equator while the other continents moved east to west.

 

-         The location of present-day continents during this time period was found by the comparison of ancient magnetic pole locations. When new volcanic material is laid down, the minerals orientate themselves with the alignment of the poles, and then solidify.

 

-         The amount of rock exposed to the air increased significantly during the period. This is thought to be because of an increase in the thickness of the continental crust and to the shifting of the plates.

 

 

There were two major oceans: Panthalassic in the northern hemisphere, and the Rheic Ocean in the southern hemisphere. The Paleo-Tethys Ocean was closed in when North China collided with Siberia/Kazakstania and became a sea. The shallow Ural Sea was located between Pangaea and Siberia.

 In this picture, the orogenies take place with Siberia and Kazakstania in the north and Pangaea and Gondwanaland on the equator. The formation of the Gondwana ice sheet is seen at the South Pole.

 

Stratigraphy

 

-         The Devonian-Carboniferous boundary is marked by the appearance of the conodonts, ammonoids, and the foraminifers. All of which were marine dwelling. The Carboniferous-Permian Boundary is marked with the existence of new species of fusulinid forams.

-         The unconformity of the strata of the Carboniferous period was due to the restriction of the oceans to the continental margins and sea fluctuation. 

 

-         These forams were fossilized inside the strata of sediment deposits with some reaching up to one centimeter in length. The forams are so abundant in the rock record that some grain resembles rice, coining the term Rice Rock.

 

-          Crinoidal Limestones in the Mississippi Valley give the early Carboniferous its name. Also, the Redwall Limestone of the Grant Canyon, the Madison Limestone in the Northern Rockies, and the Pahasapa Limestone in the Black Hills of South Dakota are all major sediment outcrops in the U.S.

Pahasapa Outcrop 

http://academic.emporia.edu/aberjame/struc_geo/rocky/rocky11.jpg

-         Sedimentary cycles in the Late Mississippian show repeating sets of vertical sandstone-shale-limestone strata. The sandstones and shales represent deltaic deposits created by rivers that were flowing from the southeastern region of Canada.

-         There are similar cyclothems, a complete sedimentary deposit cycle, in the characteristic coal beds of the Upper Carboniferous. Coal deposits reflect the transgressions and regressions of the Pennsylvanian period. Each layer signifies periodic flooding of the swamps in which the coal formed.

Coal Bedding

Geologists in a coal mine color-code the layers of coal ball formation.

http://www.ucmp.berkeley.edu/carboniferous/coalhorizon.jpg 

 

The End of the Carboniferous

-          The mass extinctions that mark the end of other geologic periods were not present, yet many species did go extinct during this time. The marine environments were most affected by these climate changes, so the extinctions were mostly invertebrates that spent their lives in the seas.

 

-          The end of the Carboniferous period is marked by global climate changes due to the glaciers that covered the South Pole.

  http://virtedit.free.fr/8glacier.jpg

 

 

 

 

THE CARBONIFEROUS (2008 PRESENTATION)

(Mississippian, Pennsylvanian)

By Patrick

Introduction

 

-         The Carboniferous Period is divided into the sub-periods of the Mississippian (Lower Carboniferous) and Pennsylvanian (Upper Carboniferous). It took place 354 million years ago and ended around 290 million years ago, totaling 64 million years and elapsing about 1.6 percent of geologic time.

 

-         The Mississippian takes place from about 354 to 323 mya, and the Pennsylvanian from about 323 to 290 mya. The period beginning and end is uncertain by 5 to 10 my. The period is defined by massive plants and insects that occupied the northern hemisphere while giant glaciers oscillated in the southern hemisphere, drastically affecting all aspects of life on earth.

 

-         The unique system that divides the period was developed in order to separate the coal-rich layers of the Pennsylvanian and the limestone deposits of the Mississippian. Thus explaining the differences of stratigraphy on each continent.

Biology

 

Coal swamp

An artist’s depiction of the swamplands during the Mississippian.

http://www.ucmp.berkeley.edu/carboniferous/carbforest.jpg

 

-         Marine life developed while further overtaking the increasingly scarce Trilobites, the “poster organism” for the Cambrian and Ordovician periods. Bryozoans (filter feeders) flourished alongside Brachiopods on the sea floor. Floraminiferas (Forams for short), unicellular protists with shells, were also abundant during this time.

 

-         Tetrapods gained prominence when new species laid amniote eggs, the first of their kind to have shells, protecting the unborn and enabling the Tetrapoda to dwell on land. These first walking vertebrates were mostly amphibians and reptiles. They only made up a minor percentage of the population of earth.

 

 

-         Lycopsids, seedless plants, played a vital role in the environment and were a primary source of carbon that produced the coal beds of this period. Some grew to a height of 35 meters and formed large forests. Present in few numbers today, they are the oldest vascular plants on earth.

 

-         Gastropods, bony fish, and early sharks evolved.

 

-         Near the end of the Mississippian, uplift and erosion of the land masses created new deltas and floodplains which supported less corals, crinoids, blastoids, cryozoans, and bryzoans, species that had previously been present in large quantities.

 

-         Millipedes, spiders, scorpions, and land snails roamed the swamplands. Invertebrates such as the dragonfly grew to enormous sizes.

Dragonflies

Protolindenia fossil

This fossil preserved an imprint of a dragonfly with a wingspan of 15 centimeters.

http://www.ucmp.berkeley.edu/arthropoda/uniramia/odonatoida.html

 

 

 

 

 

 

 

 

 

            Tetrapods

http://www.ucmp.berkeley.edu/vertebrates/tetrapods/amphibiamus.jpg

Conifers

http://www.ucmp.berkeley.edu/seedplants/conifers/images/lebachia.jpg

 

Paleoclimate

 

-         The Carboniferous is well-known for its vast swamps and temperate climate for the majority of the period, ending with progressively cooler temperatures due to glaciations. These swamps produced significant amounts of coal on the North American continent in the area that is now the Ohio River Valley, hence the term “Carbon-bearing.”

 

-         We know this because the plants that grew during this time lacked growth rings that are evident in plants today. This was discovered by comparing the morphology (The form and structure of an organism as a whole) of Carboniferous plant fossils with present plant life.

 

-         The Earth was much hotter and much more humid that it is presently. The atmosphere has changed greatly over the course of geologic history; however, during the end of the Pennsylvanian it had similar oxygen and carbon dioxide levels.

 

-         Warm, shallow seas flooded the continents. Coastlines fluctuated, caused by local basin subsidence and worldwide sea level changes.

 

-         As Earth entered the Pennsylvanian, the climate eventually cooled due to glaciations in Gondwanaland (South America, Africa, Antarctica, Australia, India, and the Arabian Peninsula) as it made its way closer to the South Pole. Two major ice sheets in the southern hemisphere drained the Earth of water, causing a major regression.

 

Orogenies

Image:US pennsylvanian general.jpg

The United States during the Pennsylvanian about 300 mya. The western states are under a deep ocean while the center of North America comprises a shallow sea. Swamp areas stretch as far south as central Texas and as far north as New York. On the west coast are the ancestral formations of the Sierra Nevada, then in the Midwest are the Rocky, Ozark, and Ouachita mountains, and on the east the Appalachians. These highlands supplied much of the sediment deposits in present-day North America.

 

- Three major orogenies occurred during the Carboniferous:

1)      Laurussia (Today’s Europe and North America) collided into Gondwanaland, producing the Appalachian mountain belt in eastern North America and

2)      The Hercynian Mountains in the UK.

3)      A later collision between Siberia and Eastern Europe created the Ural Mountains in western Russia.

 

 

Plate Tectonics

-         The Carboniferous is the beginning period of which the super continent Pangaea began forming. Gondwanaland shifted towards the equator while the other continents moved east to west.

 

-         The location of present-day continents during this time period was found by the comparison of ancient magnetic pole locations. When new volcanic material is laid down, the minerals orientate themselves with the alignment of the poles, and then solidify.

 

-         The amount of rock exposed to the air increased significantly during the period. This is thought to be because of an increase in the thickness of the continental crust and to the shifting of the plates.

 

 

There were two major oceans: Panthalassic in the northern hemisphere and the Rheic Ocean in the southern hemisphere. The Paleo-Tethys Ocean was closed in when North China collided with Siberia/Kazakstania and became a sea. The shallow Ural Sea was located between Pangaea and Siberia.

 

In this picture, the orogenies take place with Siberia and Kazakstania in the north and Pangaea and Gondwanaland on the equator. The formation of the Gondwana ice sheet is seen at the South Pole.

 

Stratigraphy

 

-         The Devonian-Carboniferous boundary is marked by the appearance of the conodonts, ammonoids, and the foraminifers. All of which were marine dwelling. The Carboniferous-Permian Boundary is marked with the existence of new species of fusulinid forams.

-         The unconformity of the strata of the Carboniferous period was due to the restriction of the oceans to the continental margins and sea fluctuation.

 

 

-         These forams were fossilized inside the strata of sediment deposits with some reaching up to one centimeter in length. The forams are so abundant in the rock record that some grain resembles rice, coining the term Rice Rock.

 

-         Crinoidal Limestones in the Mississippi Valley give the early Carboniferous its name. Also, the Redwall Limestone of the Grant Canyon, the Madison Limestone in the Northern Rockies, and the Pahasapa Limestone in the Black Hills of South Dakota are all major sediment outcrops in the U.S.

 

-         Sedimentary cycles in the Late Mississippian show repeating sets of vertical sandstone-shale-limestone strata. The sandstones and shales represent deltaic deposits created by rivers that were flowing from the southeastern region of Canada.

 

-         There are similar cyclothems, a complete sedimentary deposit cycle, in the characteristic coal beds of the Upper Carboniferous. Coal deposits reflect the transgressions and regressions of the Pennsylvanian period. Each layer signifies periodic flooding of the swamps in which the coal formed.

Pahasapa Outcrop

http://academic.emporia.edu/aberjame/struc_geo/rocky/rocky11.jpg

 

Coal Bedding

Geologists in a coal mine color-code the layers of coal ball formation.

http://www.ucmp.berkeley.edu/carboniferous/coalhorizon.jpg

 

The End of the Carboniferous

Out with the old, in with the new:

-         The expansion and retreat of Gondwanaland’s glaciers caused periodic extinctions of aquatic life while terrestrial organisms dominated Euroamerica, China, and Siberia/Kazakstania. This rapid climate change caused vegetational changes that resulted in less seedless lycopsids and more seeded plants. The plants began at high latitudes and by the Carboniferous-Permian boundary spread all the way to the equator.