The Mesozoic Era is one of three geologic eras of the Phanerozoic eon. The division of time into eras dates back to Giovanni Arduino in the 18th century, although his original name for the era now called the Mesozoic was "Secondary" (making the modern era the Tertiary). Lying between the Paleozoic and the Cenozoic, Mesozoic means "middle animals" in Greek: meso for middle and zoion for animals. It is often called the "Age of Medieval Life" or the "Age of the Dinosaurs", after the dominant fauna of the era.

The Mesozoic was a time of tectonic, climatic, and evolutionary activity. The continents gradually shifted from a state of connectedness into their present configuration; this rifting provided for speciation and other important evolutionary developments. The climate was exceptionally warm throughout the period and also played an important role in the evolution and diversification of new animal species. By the end of the era, the basis of modern life was in place.

Geologic periods

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USGS Newsroom

Media Advisory: Join Scientists to See How Major Earthquake Can Devastate Southern California
OC_Web@usgs.gov (Office of Communications Web Group)Some residents were shaken awake today by the magnitude 4.1 earthquake in the San Bernardino Mountains. But all of Southern California would experience the effects of the magnitude 7.8 earthquake on the San Andreas Fault - 500,000 times bigger than today's event - depicted in the "ShakeOut Earthquake Scenario." The scenario will be used Nov. 13 for The Great Southern California ShakeOut, the largest earthquake drill in U.S. history. Media are invited to be briefed by scientists and see firsthand how the scenario depicts the devastation a major earthquake could cause to Cajon Pass, a narrow area between mountain ranges that is a primary corridor for highway and rail transportation, vital power lines, the California aqueduct, energy pipelines and telecommunications cables that supply millions of homes and businesses in Southern California. The tour will include great visual and audio material for print and broadcast media. WHO: USGS earthquake experts Lucy Jones and Ken Hudnut, representatives from the California Geological Survey WHEN: Wednesday, October 8, 2008, at 12:30 p.m. WHERE:  Media should meet on the east side of the parking lot at the Ontario Airport Marriott, beside Gusti Road. Vans will be provided for transportation to the location in Cajon Pass, approximately 20 minutes away, or media can follow in their own vehicles. Driving directions to the Marriott are available on the Marriot Web site. Media can also go to the Cajon Pass site directly at 1:00 p.m., near the junction of I-15 and I-215 N following the map instructions provided. WHY: Take this time to prepare for The Great Southern California Shakeout, which already has more than 3.7 million people, schools and businesses signed up to participate. In the "ShakeOut Earthquake Scenario," the earthquake would kill 1,800 people, injure 50,000, cause $200 billion in damage, and have long-lasting social and economic consequences. This is the most comprehensive analysis ever of what a major Southern California earthquake would mean and is the scientific framework for what will be the largest earthquake preparedness drill in the nation's history.
Hurricane Ike's Effects Linger in the Great Lakes
OC_Web@usgs.gov (Office of Communications Web Group)Videos, pictures, and real-time data show damage from Ike along the Lake Michigan shore near Portage, Ind. Although Hurricane Ike is long gone, its impact lingers more than a thousand miles from where it made landfall.  Runoff from tributaries dumped massive amounts of sediment into Lake Michigan, contaminating the water, compromising near-shore navigation and raising E coli bacteria to levels unsafe for swimming.  According to Richard Whitman, a U.S. Geological Survey (USGS) expert on beach health, "The local effects that Ike had on Lake Michigan's Indiana shoreline, water depth, and water quality have been profound." While assessing Ike's impact on the lake, Whitman noted that "The velocity and height of a tributary emptying into Lake Michigan at Portage, Indiana went off the chart.  We measured a tremendous amount of sediment accumulation Near Ogden Dunes." USGS scientists use high tech, state-of-the-art equipment in the lake to measure runoff, the lake's currents, and sediment input during storms. These data are used to forecast whether a beach is unsafe for swimmers. Beaches are subject to high bacteria levels following storms. Heavy rains from Ike significantly impacted northwestern Indiana and Chicago because the ground was already saturated by a stalled cold front.
New Geologic Map Provides Details on Past, Present and Future of Western Transverse Ranges
OC_Web@usgs.gov (Office of Communications Web Group)Do you ever wonder what has happened beneath your feet? Curious about what might occur in years to come? A new tool that can help citizens who live, work and play in the western Transverse Ranges region is now available online and in print from the U.S. Geological Survey (USGS). The Geologic Map of the Eastern Three-Quarters of the Cuyama 30' x 60' Quadrangle, California. Geological Survey Scientific Investigations Map 3002, is available for purchase or free download. A low-resolution image of the map is attached. Geologic maps serve as the framework for a number of planning and industrial activities because they show the rock types at the earth's surface and help to unravel the history of the earth. They can help inform land-use decisions such as how planners should design buildings, canals, roads, and drainage of farmland, locate earthquake faults, and show where landslides are likely to occur to help plan for safer communities. They can also help predict where resources such as oil, gas, and mineral resources exist for future development. "Geologic maps are important tools for policy makers, planners and the general public," said Eugene Schweig, USGS geologist and Chief Scientist of the Central Region Earth Surface Processes team. The newly released USGS map represents part of the Transverse Ranges, east-west trending mountains in southern California that include the San Bernardino, San Gabriel, Santa Monica, and Santa Ynez Mountains. The map also includes a large section of the San Andreas fault that ruptured during the major 1859 Ft. Tejon earthquake.  It shows surface-level rocks and deposits being formed and deformed today, and others that formed as long as 1.7 billion years ago. An accompanying pamphlet describes in detail the geologic units of the region, most of which are less than about 50 million year old (Tertiary age) and include both marine and non-marine rocks.
New Geologic Map Provides Details on Past, Present and Future of the Colorado Front Range
OC_Web@usgs.gov (Office of Communications Web Group)Do you ever wonder what has happened beneath your feet? Curious about what might occur in years to come? A new tool that can help citizens who live, work and play in the Colorado Front Range is now available online and in print from the U.S. Geological Survey (USGS). The Geologic Map of the Denver West 30' x 60' Quadrangle, North-Central Colorado, USGS Scientific Investigations Map 3000, is available for purchase or free download. A low-resolution image of the map is attached. Geologic maps serve as the framework for a number of planning and industrial activities because they show the rock types at the earth's surface and help to unravel the history of the earth. They can help inform land-use decisions such as how planners should design buildings, canals, roads, and drainage of farmland, locate earthquake faults, and show where landslides are likely to occur to help plan for safer communities. They can also help predict where resources such as oil, gas, coal, and mineral resource exist for future development. "Geologic maps are important tools for policy makers, planners and the general public," said Eugene Schweig, USGS geologist and Chief Scientist of the Central Region Earth Surface Processes team. "They are especially useful in a major urban area like Denver due to the ecological balance this population craves." The newly released USGS map includes the western part of the Denver metropolitan area and many rapidly growing mountain communities and recreation areas, including a section of the valuable Colorado mineral belt.  It shows rocks and deposits being formed at the surface today and others that formed as long as 1.7 billion years ago. An accompanying pamphlet describes the geologic history of the region and the potential for a number of geologic hazards apparent in the mapping area. The last USGS geologic map that covered this part of the Front Range was produced in 1981. The new Denver West map includes many previously unmapped areas, including deposits of young surface material such as alluvial gravel and glacial till, and shows previously mapped areas in greater detail.
Substantial Power Generation from Domestic Geothermal Resources
OC_Web@usgs.gov (Office of Communications Web Group)Geothermal power production could significantly add to the electric power generating capacity in the United States.  The U.S. Geological Survey assessment released today is the first national geothermal resource estimate in more than 30 years. The results of this assessment show that the United States has an estimated 9,057 Megawatts-electric (MWe) of power generation potential from domestic, conventional, identified geothermal systems, 30,033 MWe of power generation potential from conventional, undiscovered geothermal resources, and 517,800 MWe of power generation potential from unconventional (high temperature, low permeability) Enhanced Geothermal Systems (EGS) resources.  The results of this assessment indicate that full development of the conventional, identified systems alone could expand geothermal power production by approximately 6,500 MWe, or about 260% of the currently installed geothermal total of more than 2500 MWe.  The resource estimate for unconventional EGS is more than an order of magnitude larger than the combined estimates for both identified and undiscovered conventional geothermal resources and, if successfully developed, could provide an installed geothermal electric power generation capacity equivalent to about half of the currently installed electric power generating capacity in the United States. "The results of this assessment point to a greater potential for geothermal power production than previous assessments," said Dirk Kempthorne, U.S. Secretary of the Interior. "Geothermal energy is not only a renewable resource, but could significantly contribute to our domestic energy resource base." Results of this USGS assessment indicate that the power generation potential from identified geothermal systems range from 3,675 MWe (95% probability) to 16,457 MWe (5% probability); the power generation potential from undiscovered geothermal systems range from 7,917 MWe (95% probability) to 73,286 MWe (5% probability); and the power generation potential from Enhanced Geothermal Systems range from 345,100 MWe (95% probability) to 727,900 MWe (5% probability). Geothermal energy is an extremely important but underutilized domestic, renewable energy resource.  The nearly 15,000 Gigawatt-hours of geothermal power generated in 2005 constituted 25% of domestic nonhydroelectric renewable electric power generation (a little over 4,055,400 total Gigawatt-hours of electricity were produced in the United States in 2005).  The USGS assessment evaluated 241 identified moderate-temperature (90 to 150oC; 194 to 302oF) and high-temperature (greater than 150oC) geothermal systems located on private and public lands.  Geothermal systems located on public lands closed to development, such as national parks, were not included in this assessment.  Electric-power generation potential was also determined for several low-temperature (less than 90oC) systems in Alaska for which local conditions make electric power generation feasible.  The assessment also included a provisional estimate of the power generation potential from the application of unconventional, EGS technology. This assessment benefited from cooperation with the Department of Energy, Bureau of Land Management, the University of Nevada - Reno, the University of Utah, Idaho National Laboratory, Lawrence Berkeley National Laboratory, state and local agencies, and the geothermal industry. To learn more about USGS National Geothermal Resource efforts and to see results of the assessment, please visit the Energy Resources Web site.
Images of Texas Neighborhood Devastated by Hurricane Ike Now Online
OC_Web@usgs.gov (Office of Communications Web Group)Before-and-after Hurricane Ike photographs showing the near total destruction of a coastal neighborhood in Texas are now accessible online. On Monday, Sept. 15, a team of U.S. Geological Survey (USGS) scientists flew the coast impacted by Hurricane Ike and acquired photographs and video. Images of Crystal Beach, Texas, on the Bolivar Peninsula are compared to aerial photographs of the same area taken Sept. 9, several days before Ike's landfall, and are now available from the USGS at http://coastal.er.usgs.gov/hurricanes/ike/photo-comparisons/bolivar.html. "The Bolivar Peninsula was in or near the right eyewall of Hurricane Ike when the storm made landfall," said USGS scientist Abby Sallenger. "This was the location of the strongest winds and where we observed the greatest impacts to the coast." Storm surges and waves crested Crystal Beach and swept sand inland, along with the remains of homes. The four sets of before-and-after photographs posted online show these extreme changes to the residential area. While the maximum impacts of Ike were on the Bolivar Peninsula, vast areas of Louisiana and Texas were flooded by storm surge, Sallenger said. Beaches served as rims that contained the flood waters, and water continues to extend landward in some places for tens of kilometers. The before-and-after images were taken during airborne surveillances of the Gulf shore from western Louisiana to south of Galveston, Texas. Additional USGS photograph comparisons will be posted on the web site in the coming days to show how Ike's aftermath varies across the entire impact zone.  A pair of photographs is attached.

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