1
Where does it fall in Geological Time Scale?
The Pennsylvanian time period is a subperiod of the Carboniferous that lasted from 320 million
years ago to 290 million years ago.
The Carboniferous time period is only subdivided as the Mississippian and Pennsylvanian here in
the U.S. The McGraw-Hill encyclopedia informs us that “the Pennsylvanian has been widely recognized
as a geologic period and derives its name from a thick succession of mostly nonmarine, coal-bearing
strata in Pennsylvania.” (McGraw-Hill, 2006)
McGraw-Hill also informs us that this time period is termed differently when they state that “In
northwestern Europe, strata of nearly equivalent age are commonly designated as Upper Carboniferous
and in eastern Europe as Middle and Upper Carboniferous.”
”
2
What did the continents and sea levels of Earth look like during this time period?
The continents during this time period, according to McGraw-Hill, “Pennsylvanian
paleogeography changed significantly during the period as the supercontinent Pangaea gradually was
formed by the joining together of Gondwana and Laurasia”
Laurasia: North America and Europe
Northern Gondwana: South America and Northwestern Africa
3
Because of the convergence of continental plate boundaries, you had massive mountain building
along the convergence zones and which formed the “Ouachita–Southern Appalachian–Hercynian
geosyncline.”
Ouachita and Southern Appalachian Mountains: extend into Arkansas and Texas.
Hercynian Mountain Range: Europe, Northwestern Africa, South America.
4
Sea Level:
“[In the] Pennsylvanian [time] period, there was at least one great submergence. In the E[astern]
United States great deltas of sediments, now represented by the Pottsville conglomerate” (The Columbia
Encyclopedia, 2008), Pottsville, PA is where these sedimentary rock layers where first found.
“The sea level also oscillated during the period and caused the formation of great marshes with
extensive vegetation that was later transformed into coal” (The Columbia Encyclopedia, 2008).
“The inland waters were inhabited by fishes, clams, and various crustaceans; the oceans, by
mollusks, crinoids, sea urchins, and one-celled foraminifera” (The Columbian Encyclopedia, 2008).
5
“Repeating sequences of sedimentary rock layers record these changes in sea level”
(www.encyclopedia.com)
“Much of North America remained a stable, low-lying cratonic platform during the Pennsylvanian
and was covered by a relatively thin veneer of shallow-water marine carbonates and marine and
nonmarine clastic sediments. These were deposited as sea level repeatedly rose and fell as the polar
glaciers of southern Gondwana contracted and expanded” (McGraw-Hill, 2006)
What was the climate of the planet like?
“A major ice age with a complicated cycle running through the Carboniferous (Mississippian and
Pennsylvanian) and early Permian” (Ice Ages, 1988)
The advancing and retreating glaciers raised and lowered sea level, which flooded some of the
continental shelves to create shallow seas.
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” At least half the species in clastic wetlands were eliminated by changing climatic conditions,
probably protracted moisture deficits or exaggeration of seasonal dryness. Independent studies
suggest that the end of the Westphalian was marked by deglaciation in Gondwana and increase in
global temperature” (www.lyellcollection.org).
“Late Carboniferous and Early Permian strata record the transition from a cold interval in
Earth history, characterized by the repeated periods of glaciation and deglaciation of the
southern pole, to a warm-climate interval” (Annual Review of Earth and Planetary Sciences, 2001).
7
Was the organism terrestrial, aquatic, or marine?
Large Dragonfly (Meganeura mony): Terrestrial
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Works Cited
Pennsylvanian. (2006). In McGraw-Hill Concise Encyclopedia of Science and Technology. Retrieved from
http://ezproxy.lib.umb.edu/login?url=http://www.credoreference.com.ezproxy.lib.umb.edu/entry/conscitech
/pennsylvanian
Carboniferous period. (2008). In The Columbia Encyclopedia. Retrieved from
http://ezproxy.lib.umb.edu/login?url=http://www.credoreference.com.ezproxy.lib.umb.edu/entry/columency
/carboniferous_period
Ice ages. (1988). In Illustrated Dictionary of Science, Andromeda. Retrieved from
http://ezproxy.lib.umb.edu/login?url=http://www.credoreference.com.ezproxy.lib.umb.edu/entry/andidsci/ic
e_ages
Palaeoecological and possible evolutionary effects of early Namurian (Serpukhovian, Carboniferous)
glacioeustatic cyclicity . Journal of the Geological Society, 2008, 165:993-1005,
RESPONSE OF LATE CARBONIFEROUS AND EARLY PERMIAN PLANT COMMUNITIES
TO CLIMATE CHANGE1
Annual Review of Earth and Planetary Sciences
Vol. 29: 461-487 (Volume publication date May 2001)
DOI: 10.1146/annurev.earth.29.1.461
"Pennsylvanian Period." World of Earth Science. 2003. Encyclopedia.com. 13 Nov. 2012
<http://www.encyclopedia.com>.
Pictures
http://higheredbcs.wiley.com/legacy/college/levin/0471697435/chap_tut/chaps/chapter11-05.html
http://www.discoveringfossils.co.uk/how_britain_formed.htm
http://dragonflyevolution.wikispaces.com/Extinct+Dragonfly