The Pennsylvanian is an epoch of the Carboniferous period lasting from roughly 325 Ma to 286 Ma (million years ago). As with most other geologic periods, the rock beds that define the period are well identified, but the exact date of the start and end are uncertain by a few million years. The Pennsylvanian is named after the state of Pennsylvania where rocks from this age are widespread.

In North America, where the early Carboniferous beds are primarily marine limestones, it is treated as a full fledged geologic period between the Mississippian and the Permian. In Europe, the Mississippian and Pennsylvanian are one more-or-less continuous sequence of lowland continental deposits and are lumped together as the Carboniferous period.

Refer to the Carboniferous period article for information on faunal stages, climate, etc.

More on [ Pennsylvanian ]

USGS Newsroom

August Science Picks — Leads, Feeds and Story Seeds
OC_Web@usgs.gov (Office of Communications Web Group)In this edition of Science Picks, discover new information on the Arctic's oil and gas resources, learn about a magnitude-5.4 earthquake that rattled Los Angeles, and find out about recent explosive eruptions of volcanoes in Alaska. Learn about carbon farming, a plague vaccine for endangered ferrets, and how lead shot and sinkers are impacting nearby fish and wildlife. The 2008 Olympics games are underway; do you know how the Chinese culture is being incorporated into the medals? Learn about these science facts and much more! If you would like to receive Science Picks via e-mail, would like to change the recipient, or no longer want to receive it, please e-mail jrobertson@usgs.gov. August Highlights: 90 Billion Barrels of Oil and 1,670 Trillion Cubic Feet of Natural Gas Assessed in the Arctic Magnitude-5.4 Earthquake Rattles Los Angeles Area Explosive Eruption of Kasatochi, Cleveland, and Okmok Volcanoes in Alaska Carbon Farm: Capturing Atmospheric CO2 Ouch! Taking a Shot at Plague: Vaccine for Endangered Ferrets Lead Shot and Sinkers: Weighty Implications for Fish and Wildlife Health Olympic Medals: New Design Reflects Chinese Culture Spring Nutrient Delivery to the Gulf Estimated Among Highest in Three Decades Climate Impacts Mosquito Abundance in California Prehistoric Packrats Piled Up Clues to Climate Change Parasites Weigh In: Small Size - Big Impact Unsure about Climate Change? Just ask your Local Fish and Big-Game Species The First Step Home? Salmon's Journey Back to Upper Klamath Lake Saltwater Contamination Monitored Daily in Brunswick, Ga.
Ancient Bacteria Uses Arsenic to Grow
OC_Web@usgs.gov (Office of Communications Web Group)Scientists have discovered ancient bacteria that rely on arsenic, rather than water, to grow during photosynthesis.  Analysis indicates that this process probably dates back a few billion years.  This discovery adds an important new dimension to the arsenic cycle and highlights a previously unsuspected process that may have been essential for establishing the arsenic cycle on the ancient Earth. Results are published in Science. Scientists sampled two small hot spring-fed ponds on the south-eastern shore of Paoha Island in Mono Lake, CA. The springs were termed "green" and "red" based on the colors of the microbiological films in the pools that were studied. Samples from these springs oxidized the highly toxic Arsenic(III) to the less toxic and less mobile  Arsenic(V) by light-dependent  photosynthetic reaction that occurred in the absence of oxygen. The scientists also isolated a photosynthetic bacterium that demonstrated As(III)-dependent growth under anoxic conditions. NASA's Exobiology Program helped to fund the research along with the USGS. Collaborating colleagues in the diverse, team-oriented aspects of the experimental work were from Duquesne University (Prof. J.F. Stolz; Pittsburgh, PA) University of Georgia (Prof. J.T. Hollibaugh and Dr. J.Fisher); Athens, GA), Southern Illinois University (Prof. M. Madigan, and Dr. M.Asao), the USGS in Menlo Park, CA (Dr. R.S. Oremland, Dr. T.R. Kulp, S.E. Hoeft, and L.G. Miller) and the USGS Water Science Center in Maine (C.W. Culbertson).  Arsenic is a chemical element and is a natural constituent of the Earth's crust. It occurs naturally in rocks, soil, water, air, plants and animals. When in the natural environment, arsenic usually binds to other molecules, such as those found in soils, and does not tend to travel very far. The average concentration of arsenic in soils in the United States varies considerably. Arsenic can be released into the environment through natural processes such as volcanic activity, erosion of rocks and forest fires. Human actions, such as agricultural practices, mining, smelting and combustion of fossil fuels also contribute to arsenic releases in the environment.
Strategy to Assess the Nation's Ground-Water Availability
OC_Web@usgs.gov (Office of Communications Web Group)Scientists proposed a strategy to study the Nation's ground-water supply as part of the Federal government's effort to help address the Nation's increasing competition for water. Declines in ground-water levels have led to concerns about the future availability of ground water, which provides half the country's drinking water and is essential to the vitality of agriculture and industry, as well as to the health of rivers, wetlands, and estuaries throughout the country.  The report, "Ground-Water Availability in the United States" examines what is known about the Nation's ground-water availability and outlines a strategy for future national and regional studies that would provide information to help state and local agencies make informed water-availability decisions. View the report on-line at http://pubs.usgs.gov/circ/1323/. "An assessment of ground-water availability is critical for state and local agencies to make decisions about important issues such as drinking water, industrial and energy production, and agricultural uses," says William Alley, USGS Office of Ground Water Chief. The approach outlined in the report is designed to provide useful regional information for State and local agencies who manage ground-water resources, while providing the building blocks for a national assessment. The report places the regional studies by the USGS Ground-Water Resources Program as a long-term effort to understand ground-water availability in major aquifers across the Nation. The report contains information about 30 regional principal aquifers and five case studies to illustrate the diversity of water-availability issues. The report is written for a wide audience interested or involved in the management, protection, and sustainable use of the Nation's water resources.  Ground water, a hidden resource found below the surface of the Earth, is among the Nation's most important natural resources. Extensive use of ground-water resources and other effects of pumping has led to concerns about the future availability of ground water to meet domestic, agricultural, industrial, and environmental needs. Determining ground-water availability is a complex process. Issues affecting ground-water vary from location to location and commonly require analysis in the context of ground-water flow systems to achieve a meaningful perspective. Even if water resources are abundant regionally, heavy water use in centralized areas can create local stresses. As water-related problems evolve in complex ways, an up-to-date and comprehensive evaluation of ground-water resources that builds on the foundation of previous studies is needed to meet society's ever-changing water demands. This report is an outgrowth of a pilot study, National Assessment of Water Avail­ability and Use, that began in 2005 at the request of Congress. The report also builds on regional ground-water availability studies recently undertaken as part of the USGS Ground-Water Resources Program. The approach to national ground-water assessment is a key element of the water census of the United States, which has been proposed as part of the proposed Federal science strategy to meet nationwide water chal­lenges by the National Science and Technology Council Subcommittee on Water Availability and Quality.
Don't be Left Out! Three Months to ShakeOut
OC_Web@usgs.gov (Office of Communications Web Group)Thousands Join Each Day, You Can Too Three months from today, at 10 a.m. on November 13, millions of southern Californians will drop to the ground, take cover under a table or desk, and hold on. An earthquake prediction? No. But it is certain that the Great Southern California ShakeOut is on track to being the largest earthquake drill in United States history. As of today, over 1.7 million people have been registered at www.ShakeOut.org, with over 200 schools and districts leading the effort by scheduling their annual earthquake drills on November 13. The goal is to involve at least 5 million people. "Something remarkable is happening-people are seeing this as an unprecedented opportunity to really get themselves, their organizations, and their communities prepared," said Mark Benthien, director for Outreach at the Southern California Earthquake Center at USC. Many participants will go even further with full-scale drills of how they will speed their recovery in a massive earthquake. "Every day we hear from schools, businesses, and many others about what they are planning and how they are excited to be a part of the ShakeOut, and to encourage others to participate." Why? An enormous earthquake is in Southern California's future, and the ShakeOut Drill is a chance to practice so residents are ready when it happens. ShakeOut is based on a potential magnitude 7.8 earthquake on the southern San Andreas Fault-approximately 5,000 times larger than the magnitude 5.4 earthquake that shook southern California on July 29. Dr. Lucy Jones of the U.S. Geological Survey has led a group of over 300 scientists, engineers, and others to study the likely consequences of this potential earthquake in great detail. The result is the ShakeOut Earthquake Scenario (urbanearth.usgs.gov), which is also the basis of this year's statewide emergency response exercise, Golden Guardian 2008 (www.ohs.ca.gov). "All this is coming together in a way that has never happened before," said Dr. Jones. "What's really rewarding as a scientist is to see how the scientific foundation provided by the ShakeOut Scenario seems to be inspiring real preparedness actions throughout the region. This is important because it's what we do now, before a big earthquake, that will determine what our lives will be like after."  Detailed instructions for how to participate and get prepared for earthquakes are on the ShakeOut website. Here are key aspects of the ShakeOut: ShakeOut is organized by the Earthquake Country Alliance (ECA), a partnership of earthquake professionals, emergency responders, business leaders, and community activists. The group has been planning the ShakeOut since 2006.  Major organizations include the USGS, Southern California Earthquake Center, California Office of Emergency Services, City of Los Angeles, Art Center College of Design, State Farm, and California Institute of Technology. To be able to reach communities throughout southern California, the ECA is launching "Regional Associate" groups in each county: The San Bernardino County group has its initial meeting today and is co-chaired by County Supervisor Brad Mitzenfelt and ESRI President Jack Dangermond. The Los Angeles Group will meet on August 21 and is led by County Fire Chief P. Michael Freeman.  Riverside County Associates are led by County Emergency Manager Peter Lent and Congresswoman Mary Bono. San Diego County Associates are led by County Emergency Manager Ron Lane and two Fire Chiefs.  Orange County Associates are led by County Emergency Manager Donna Boston. Associate groups for other counties are in formation. Sponsors of the Great Southern California ShakeOut activities include USGS, National Science Foundation, FEMA, California Office of Emergency Services, City of Los Angeles, State Farm, California Earthquake Authority, Kaiser Foundation Health Plan, Tyco Electronics, Provention Consortium, Dewberry, Degenkolb, Network for Earthquake Engineering Simulation, Institute for Business & Home Safety, ABC7, and others soon to be announced. Organizations wishing to support ShakeOut activities can learn more at www.ShakeOut.org/sponsors. In addition to the ShakeOut drill, the City of Los Angeles and the Earthquakes and Megacities Initiative are hosting an International Earthquake Conference November 12-14, bringing together over 45 international experts to discuss policy, planning, and preparedness with U.S. counterparts. Online registration is available, and early registration incentives are available through the end of August. More information can be found at www.iec.lacity.org. On Friday, November 14, Art Center College of Design will present the "Get Ready Rally" at the new Nokia LA Live in downtown Los Angeles to engage the public in earthquake preparedness. All southern Californians are invited to celebrate the success of the Drill and share their experiences. There will be food, entertainment, and vendors. To participate, go to www.ShakeOut.org and pledge your family, school, business, or organization's participation in the drill. Registered participants will receive information on how to plan their drill, encourage others to participate, and improve their earthquake preparedness. It all begins with registering, which is free and open to everyone.
Drought Conditions in Western North Carolina Even Worse Than Last Year
OC_Web@usgs.gov (Office of Communications Web Group)Editors Note: Maps and graphs are on the USGS North Carolina Drought Watch Web site.  Streamflow in the French Broad River at Asheville has reached the lowest level since 1895 when the U.S. Geological Survey first began making measurements at the site. On Sunday, the streamflow was about 121 million gallons per day (Mgd), or 188 cubic feet per second.   Previously, the lowest flow at the site occurred in 2002 when the flow was 139 Mgd. Before 2002, streamflow in the French Broad River at Asheville had not been below 155 Mgd since 1925.   Last year, when much of North Carolina was in exceptional drought, the lowest flow in the French Broad was 199 Mgd.   Most of southwest North Carolina (18 counties) remains in an exceptional drought and virtually all of western North Carolina is in extreme (15 counties) or severe (8 counties) drought as the state moves into the driest time of the year. (See the North Carolina Drought Management Advisory Council Web site for the latest North Carolina drought conditions.)  Monthly average streamflows were at all-time record lows for the months of June and July at more than half of the USGS long-term streamflow gages in western North Carolina.  For example, in the French Broad River at Asheville, the July 2008 flow was 20 percent lower than the previous lowest July average flow in 1986.  Minimum record streamflows also are being recorded in the Yadkin, Catawba, and Broad River basins of North Carolina.  With a few exceptions, streamflows throughout much of the rest of the State remain at about half, or less, of normal conditions for this time of year  Ground-water levels in western North Carolina are about 2 - 5 feet below normal for this time of year, although no record minimum levels have been recorded. The number of ground-water monitoring wells across the state is relatively small, and records only extend back about 30 years at a few sites.  A monthly summary of conditions at unregulated streamflow sites and ground-water monitoring sites is available at the North Carolina Water Science Center Web site and all North Carolina USGS streamflow and ground-water data are available at the National Water Information System, Water Data for North Carolina.  The USGS and its federal, state, and local cooperators maintain 274 streamgaging stations and 62 monitoring wells throughout North Carolina.
Third Aleutian Volcano Erupts Explosively
OC_Web@usgs.gov (Office of Communications Web Group)   Kasatochi Volcano in Alaska's Aleutian Islands erupted explosively Aug. 7, sending an ash plume more than 35,000 feet into the air and forcing two biologists from the U.S. Fish and Wildlife Service to evacuate the island. "Kasatochi went from a quiet volcano to an explosive eruption within 24 hours and with very little warning," said USGS volcano scientist Marianne Guffanti. "We are thankful our colleagues were able to get out before the eruption began. They were rescued just in time by a local fishing boat."  Related Podcasts Kasatochi Volcano Erupts Explosively Download directly | Details   or subscribe by e-mail. Kasatochi is the third volcano to erupt in the Aleutian Islands in three weeks. Okmok Volcano erupted unexpectedly and explosively on July 12, followed by Cleveland Volcano, 100 miles away, on July 21. Both volcanoes sent ash plumes skyrocketing and caused commercial airline flights to be diverted or cancelled.  Scientists relied on seismic instruments on other volcano networks in the area to detect activity at Kasatochi volcano.  "Fortunately, the existing seismic networks on nearby volcanoes picked up the activity at Kasatochi volcano," said Tom Murray, scientist-in-charge of the Alaska Volcano Observatory (AVO). "They were installed with funding from the Federal Aviation Administration to reduce the hazard to aviation from volcanic ash. These networks were crucial in recognizing that this volcano had entered the first stage of a major eruption." "Our hope is to have monitoring equipment on all volcanoes that pose the greatest threats to public safety," said Guffanti. "Satellite imagery is useful to see the big picture of what is happening and what is going into the atmosphere. But direct instrumentation, such as placing seismic monitors around a volcano, will help give an early warning and give people more time to plan for hazardous events."  Scientists are working around the clock to monitor the volcanoes and keep the public and emergency responders informed.  Listen to a podcast interview with Guffanti at http://www.usgs.gov/corecast/details.asp?ID=91. You can learn about the USGS Volcano Hazards Program at http://volcanoes.usgs.gov. The AVO is a partnership of the USGS, University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys. Information about all of the current volcanic eruptions in Alaska including activity statements, images, background materials and related hazards can be found at the AVO home page: http://www.avo.alaska.edu.

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