Radiolarians (also radiolaria) are amoeboid protozoa that produce intricate mineral skeletons, typically with a central capsule dividing the cell into inner and outer portions, called endoplasm and ectoplasm. They are found as plankton throughout the ocean, and because of their rapid turn-over of species, their tests are important diagnostic fossils found from the Cambrian onwards. Some common radiolarian fossils include Actinomma, Heliosphaera and Hexadoridium.

Description

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Radiolarians have many needle-like pseudopods supported by bundles of microtubules, called axopods, which aid in flotation. The nuclei and most other organelles are in the endoplasm, while the ectoplasm is filled with frothy vacuoles and lipid droplets, keeping them buoyant. Often it also contains symbiotic algae, especially zooxanthellae, which provide most of the cell's energy. Some of this organization is found among the heliozoa, but those lack central capsules and only produce simple scales and spines.

The main class of radiolarians are the Polycystinea, which produce siliceous skeletons. These include the majority of fossils. They also include the Acantharea, which produce skeletons of strontium sulfate. Despite some initial suggestions to the contrary, genetic studies place these two groups close together. They also include the peculiar genus Sticholonche, which lacks an internal skeleton and so is usually considered a heliozoan.

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USGS Newsroom

Extreme Coastal Changes and Storm Surge Measurements from Hurricanes Ike and Gustav
OC_Web@usgs.gov (Office of Communications Web Group)What: Reporters are invited to attend a special presentation about the impacts of Hurricanes Ike and Gustav on the Texas and Louisiana coast. Compelling before-and-after photographs of the storms will be Bolivar Peninsula before and two days after Ike presented during an earth-science conference in Houston, October 6.   "Extreme storms like Hurricanes Ike and Gustav can change the shape and position of the coast as well as destroy buildings," said U.S. Geological Survey (USGS) oceanographer Abby Sallenger. Dr. Sallenger's expertise includes quantifying the changes wrought by the recent hurricanes using airborne-laser mapping, known as lidar. Mike Turco, USGS hydrologist in Houston, will discuss the deployment and success of using high tech, special sensors designed to measure Hurricane Ike's storm surge along the Texas and Louisiana coasts. Who:      Asbury Sallenger                USGS Florida Integrated                Science Center                St. Petersburg, Florida                    Michael Turco                USGS Texas Water                Science Center                Houston, Texas                                                                                                                                                                     When:    Monday, October 6                12:15-1:15pm   Where:  Geological Society of America Annual Meeting                George R. Brown Convention Center                General Assembly Theater B                Houston, Texas   Can't make it to Houston? This session will be webcast.  Please visit: https://www.acsmeetings.org/programs/events/webcasts/  To arrange an interview, please contact the GSA Newsroom on 1-713-853-8329. See images online at: http://coastal.er.usgs.gov/hurricanes/index.html Bolivar Peninsula before and two days after Ike
Most Alaskan Glaciers Retreating, Thinning, and Stagnating, Says Major USGS Report
OC_Web@usgs.gov (Office of Communications Web Group)Editors and Reporters: To interview the author during the Geological Society of America meeting, please contact the GSA Newsroom on 1-713-853-8329. Molnia will be presenting a poster (#76-3) at GSA on Wednesday, Oct. 8, from 8 a.m. to noon in Exhibit Hall E. Most glaciers in every mountain range and island group in Alaska are experiencing significant retreat, thinning or stagnation, especially glaciers at lower elevations, according to a new book published by the U.S. Geological Survey. In places, these changes began as early as the middle of the 18th century. Although more than 99 percent of Alaska's large glaciers are retreating, a handful, surprisingly, are advancing. The Glaciers of Alaska, authored by USGS research geologist Bruce Molnia, represents a comprehensive overview of the state of the glaciers of Alaska at the end of the 20th century and beginning of the 21st century. Richard Williams Jr., an emeritus senior research glaciologist with the USGS, said the 550-page volume will serve as a major reference work for glaciologists studying glaciers in Alaska in the years and decades to come. The report uses a combination of satellite images, vertical aerial photographs (black-and-white and color-infrared photos taken from airplanes, looking straight down), oblique aerial photographs (color photos taken from the air at an angle, such as most regular photos), and maps, supported by the scientific literature, to document the distribution and behavior of glaciers throughout Alaska. The author concludes that, because of the vast areas encompassed by the glacierized regions of Alaska, satellite remote sensing provides the only feasible means of monitoring changes in glacier area and in position of termini -- the end of a glacier -- in response to short- and long-term changes in the marine and continental climates of Alaska.  Alaskan glaciers are found in 11 mountain ranges, one large island, one island chain, and one archipelago.  Details about the recent behavior of many of Alaska's glaciers are contained in this richly illustrated book, with multiple photographs and satellite images, as well as hundreds of aerial photographs by Molnia, taken during his more than four decades of work in Alaska. Three other USGS glaciologists authored two sidebar sections of the book: Columbia and Hubbard Tidewater Glaciers, by Robert M. Krimmel; and The 1986 and 2002 Temporary Closures of Russell Fiord by the Hubbard Glacier, by Bruce F. Molnia, Dennis C. Trabant, Rod S. March, and Robert M. Krimmel.  A third section, Geospatial Inventory and Analysis of Glaciers: a Case Study for the Eastern Alaska Range, was authored by William F. Manley, Institute of Arctic and Alpine Research (INSTAAR), University of Colorado. This professional paper (USGS Professional Paper 1386-K) is available in print and online at http://pubs.usgs.gov/pp/p1386k/. It is the 8th volume to be published in the Satellite Image Atlas of Glaciers of the World series; the other seven volumes are available in print and online at http://pubs.usgs.gov/fs/2005/3056/ More than 100 glaciologists from the United States and other nations have collaborated with the USGS to produce these 11 volumes. This August 1941 photograph is of Muir Glacier in Glacier Bay National Monument, Alaska. It shows the lower reaches of Muir Glacier, then a large, tidewater calving valley glacier and its tributary, Riggs Glacier. For nearly two centuries before 1941, Muir Glacier had been retreating. In places, a thickness of more than two-thirds of a mile of ice had been lost. Photo courtesy of the National Snow and Ice Data Center and Glacier Bay National Park and Preserve Archive This August 1950 photo documents the significant changes that occurred during the 9 years between photographs A and B. Muir Glacier has retreated more than 2 miles, exposing Muir Inlet, and thinned 340 feet or more. However, it still is connected with tributary Riggs Glacier. Photo courtesy of the Glacier Bay National Park and Preserve Archive       This August 2004 photo further documents the significant changes that have occurred during the 63 years between photographs A and C, and during the 54 years between photographs B and C. Muir Glacier has retreated out of the field of view and is now nearly 5 miles to the northwest. Riggs Glacier has retreated as much as 2000 ft and thinned by more than 800 feet. Note the dense vegetation that has developed. Also note the correlation between Muir Glacier's 1941 thickness and the nearly horizontal line on the mountainside on the left side of the 2004 photograph. This line that indicates the past height of the glacier is called a trimline. Photo courtesy of Bruce Molnia, USGS).   This ship-deck-based August 1980 photograph of Muir Glacier and Muir Inlet, Glacier Bay National Park and Preserve, St. Elias Mountains, Alaska, shows the nearly 200-ft-high retreating tidewater end of Muir Glacier with part of its face capped by a few angular pinnacles of ice, called séracs. Note the icebergs in the ship's wake in the lower right side of the photograph. The location of Muir's terminus is less than a mile from the landward end of Muir Inlet. Photo courtesy of Bruce Molnia, USGS       This photo was taken in September 2003; in the 23 years between photographs, Muir Glacier has retreated more than a mile and ceased to have a tidewater terminus. Since 1980, Muir Glacier has thinned by more than 600 ft, permitting a view of a mountain with a summit elevation of greater than 4000 ft, located in the center of the photograph. A reexamination of the 1980 photograph shows that the summit of this mountain was visible but that it blended in with adjacent clouds. Photo courtesy of Bruce Molnia, USGS    
"Rock Stars" to Present Geologic Findings at Houston Conference
OC_Web@usgs.gov (Office of Communications Web Group)Top scientists from across the world, including 192 earth science experts from the U.S. Geological Survey (USGS), will be gathering this week to share their latest findings and most innovative research.  The USGS will be a major participant at the annual meeting of the Geological Society of America (GSA), Oct. 5-9, 2008 at the George R. Brown Convention Center in Houston, Texas. USGS scientists will present approximately 140 papers and posters on topics ranging from the extreme coastal impacts of Hurricanes Ike and Gustav to the potential effects of moon dust on astronauts. Ecosystems "Is Las Vegas Wastewater Threatening Lake Mead Fish Reproduction?"  Contaminants in Nevada's Lake Mead might be threatening fish reproduction. Reproductive problems in male fish observed at several locations in Lake Mead include altered reproductive hormones, reduced gonadal development, and lower sperm quality-all possibly indicating exposure to contaminants in the water. Treated wastewater from the Las Vegas Metropolitan area flows into Lake Mead through Las Vegas Wash and enters into Las Vegas Bay. Studies were recently conducted to determine the distribution and potential sources of contaminants in Lake Mead and indicate that the main source is Las Vegas Wash.   Presenter: Michael R Rosen, USGS Monday, Oct. 6, 10:20 a.m., General Assembly Theater Hall C "Strategic Science Plan for Salton Sea Restoration" California's largest lake is in jeopardy, but scientists are coming to the rescue. The Salton Sea provides irreplaceable habitat for migratory birds and an important cultural and recreational resource; however, water transferred from agricultural uses in the Imperial Valley to municipal uses in southern California will decrease the amount of irrigation water returned to the lake. If no action is taken, the results will be loss of aquatic and wetland habitat, increased salt content, increased receding of the water level, and degraded air quality.  USGS scientists are assisting in restoration planning through science evaluations and oversight and collaboration on a monitoring and assessment plan.  The Strategic Science Plan will help link resource managers with the scientific community by addressing issues such as biological sustainability, water and air quality, and socioeconomic values. Presenter: Doug Barnum, USGS Wednesday, Oct. 8, 3:20 p.m., General Assembly Theater Hall B "New USGS Studies on Post-Fire Dryland Soil Stability and Habitat Restoration" Habitat restoration project results from the eastern Great Basin and the Colorado Plateau confirm the need for managers to evaluate the risks of increasing soil erosion when planning land treatments. Efforts largely funded by federal programs are underway in western North America to restore wildlands that have been degraded by effects of land-use, invasive exotic plants, and altered fire regimes. The goals are to enhance ecosystem resistance and resilience to fire, resistance to invasive exotic plants, native plant diversity, habitat quality for wildlife, and forage production for livestock. USGS scientists highlight the need to address the risks of soil erosion in such plans.  Presenter: Mark Miller, USGS Sunday, Oct. 5, 11:05 a.m., Room 332AD Climate Poster Presentation: "Soil Development and Vegetation Succession in Glacial Fiords of Southcentral and Southeast Alaska" Soil and plants are replacing many glaciers in Alaska. Glacier melts due to current climate conditions have given way to bays that contain new soils. More than 90% of Little Ice Age glaciers have been retreating since their maximum sizes were reached 100 to 250 years ago. The relationship between soil and vegetation in new bays of Kenai Fjords National Park has been studied. Results show that soil profile development increases as distance from the remaining glaciers increases and as maturity of the vegetation increases. Co-Presenter: Bruce Molnia, USGS Wednesday, Oct. 8, 8 a.m. - 12 p.m., Exhibit Hall E Energy and Minerals "Potential for Undiscovered Hydrocarbon Accumulations in Southern Louisiana-Insights from the Structural Interpretation and Restoration of 2D Seismic Lines" Scientists speculate that undiscovered gas might exist in Louisiana. The work being presented is an assessment of undiscovered hydrocarbon resources, gas compounds that are often used for energy, in underground rock layers of the Gulf Coast. Models of the underground geology have been created based on interpretations of seismic lines from southern Louisiana.  Results suggest that there are large unexplored structural traps containing hydrocarbon in rock from the Tertiary time period.  Presenter: Ofori N. Pearson, USGS Monday, October 6, 4:30 p.m., Room 351AD "Oil and Gas Near Shore in the Gulf of Mexico" The author will present a recent USGS assessment of the technically recoverable undiscovered conventional oil and gas resources in the U.S. Gulf of Mexico coastal plain and state waters. USGS estimated a mean of 83.8 trillion cubic feet of undiscovered natural gas, a mean of 396 million barrels of undiscovered oil, and a mean of 3.1 billion barrels of undiscovered natural gas liquids in the assessed Paleogene strata. Presenter: Peter D. Warwick Monday, Oct. 6, 3:15 p.m., Room 351AD Hazards Special Session: "Extreme Coastal Changes During Hurricanes Ike and Gustav" and "Mapping Hurricane Ike's Inland Storm Surge" USGS scientist Asbury Sallenger will show compelling before-and-after photographs in this late breaking storm session. Extreme storms can change the shape and position of the coast as well as destroy buildings.  The changes wrought to the coast by the recent hurricanes will be illustrated using airborne-laser mapping, known as lidar.  Mike Turco (USGS) will discuss the deployment and success of using high tech, special sensors designed to measure Hurricane Ike's storm surge along the Texas and Louisiana coasts. Presenters: Asbury (Abby) Sallenger and Michael Turco, USGS Monday, Oct. 6, 12:15-1:15 p.m., General Assembly Theater B Please visit: https://www.acsmeetings.org/programs/events/webcasts/ "Bioaccumulation of Organic Anthropogenic Wastewater Indicators in Earthworms" Earthworms studied in agricultural fields have been found to contain organic chemicals from household products and manure, indicating that such substances are entering the food chain.  Animal manure and biosolids, the solid byproduct of wastewater treatment, often are applied to agricultural crops to provide nutrients for plant growth and to improve the quality of soil. USGS and Colorado State University-Pueblo scientists have found that earthworms studied in agricultural fields where manure and biosolids were applied contain 20 different organic chemicals from household products and manure. Presenter: Chad A. Kinney, Colorado State University-Pueblo Monday, Oct. 6, 1:30 p.m.-5:30 p.m., General Assembly Theater Hall C "Geology, Health, and Security in the Global Community" Earth science is integral to international environmental security.  Using case studies from the Philippines, Indonesia, and Zambia, the talk will explain how earth scientists working in collaboration with scientists from many other disciplines can contribute to global environmental security and disaster diplomacy. The session will immediately follow a technical session in the same room (Session T203, "Geology and Health in Texas, Mexico, and Beyond"), with talks examining many international geologic and health issues. Presenter: Geoff Plumlee, USGS scientist and Outgoing Chair of the Geological Society of America's Geology and Health Division Sunday, Oct. 5, 11:30 a.m. to 11:50 a.m., Room 330B Poster Session: "A 50-state Inventory of Landslides -A U.S. Geological Survey Pilot Study" Two USGS landslide publications that help assess the risk of landslides in the U.S. will be presented. Currently, landslide occurrences in the U.S. are investigated and tracked by each one of the 50 State Geological Surveys, with no uniformity in collection or presentation methods.  This lack of uniformity presents a critical challenge for emergency preparedness in landslide-affected regions.  The USGS is providing an integrated platform for each state to post its own inventory in one place, with the intent of eventually providing a publicly-accessible one-stop means of finding the landslide history of an area. The publications being presented have used a similar landslide inventory method to assess landslide hazards for two regions, serving as examples of inventory importance. Chairs:  Helen Delano, Pennsylvania Geological Survey and Lynn Highland, USGS Landslide Program Sunday, Oct. 5, 8 a.m. - 4:45 p.m., Exhibits Hall "Land-Use and Climate Change Affecting Desert Soil Erosion" The threat of dust in dryland regions will be heightened by climate change and land use, scientists say.  Disturbance of the soil surface in dryland regions from recreation, livestock, mining and energy exploration, military exercises, and fire reduces or eliminates the natural protective cover of the soils, resulting in increased dust production.  The effects of future climate changes will also reduce cover of desert soil protectors such as plants.   Combined effects, such as surface disturbance occurring during drought periods, can create very large dust events, and these surface disturbances are likely to increase in the future. Presenter: Jayne Belnap, USGS Sunday, Oct. 5, 9:30 a.m., Room 332AD "Delta Dikes in Northwest Washington-to Build or Not to Build?" The flood protection and agricultural benefits of dikes at river deltas are often tainted by their resulting hazards. Recent surveys of large deltas in northwest Washington show a pattern of diked areas being about a meter lower than neighboring undiked areas. One explanation is that river sediments at deltas are naturally compacted over time; however, natural floods frequently deposit clay and silt sediments that compensate for this loss of land. Diked areas protected from such floods are not subject to sediment build-up and are therefore lower than nearby undiked areas. The results are loss of fishery resources, changes in wildlife habitat, lost carbon sequestration, and the ever increasing hazard of a great flood overtopping a dike. Presenter: Ralph Haugerud, USGS Monday, Oct. 6, 11 a.m., Room 352DEF "The First Line of Defense: Louisiana's Barrier Islands" Many of the islands that have served as Louisiana's first line of defense from storm surge are severely eroding. Some have retreated more than 20 yards per year. Many are not following the classic model of migrating landward with no change in form; they are diminishing in size and will eventually disappear because of subsidence, low sand supply, and impacts by extreme storms. Presenter: Asbury (Abby) Sallenger, USGS Tuesday, Oct. 7, 2:30 p.m., Ballroom C Human Health Joint Technical Session: "Developments in Aeolian Research: Bridging the Interface between Soil, Sediment, and Atmosphere II" USGS scientists will present on the dangerous effects of dry region dust emissions on human and environmental health. The potential effects of climate change, coupled with increased development of dryland areas such as Las Vegas, highlight the need for further research on the ecological and health effects of dusts from geologic sources such as dry lake beds. The pair of talks, "Dust from playas in the Mojave Desert (USA): Controls on metal contents and emission" and "Bioaccessibility of Toxic Elements In Dusts from Dry Saline Lakes In the Mojave Desert (USA)," will address the geologic and hydrologic processes that result in the presence of potentially toxic heavy metals within dry lake bed dusts, and how the dusts may affect humans and wildlife. Presenters: Rich Reynolds and Suzette Morman, USGS Wednesday, Oct. 8, 1:30 p.m., General Assembly Theater Hall B "Living on a Dusty Moon" While stardust is the stuff of fairytales, moon dust is the stuff of science.  The renewed interest in establishing a manned base on the moon demands information on the effects of moon dust on human health. The dust had substantial impacts on space suits and other equipment used in the first lunar missions, and was also well-known as a source of substantial eye, skin, and respiratory irritation to astronauts. USGS scientists will discuss recent research on the potential impacts of lunar dust on equipment and human health, and the development of a lunar soil simulant that can be used to model these impacts.   Presenters: Doug Stoeser, USGS in collaboration with NASA, and Geoff Plumlee, USGS Thursday, Oct. 9, 8 a.m., Room 310AD "New Contributions from the National Groundwater Quality Program" The USGS National Groundwater Quality Assessment (NAWQA) program is instrumental to public safety because it consistently examines the quality of ground and surface water while encompassing a broader range of scales, contaminants, and environmental settings than any other large-scale sampling program to date. Data on chemical releases, environmental characteristics, and land use have been assembled and combined with sampling results to construct models for predicting contaminant occurrence in groundwater throughout the Nation. NAWQA has also helped to focus national attention on several ground-water contaminants affecting public water supplies, including potential contaminants that had not yet received much national attention such as road salt, ground-water recharge facilities, and atmospheric deposition. Presenter: Jack Barbash, USGS Wednesday, Oct. 8, 5:15 p.m., Room 352DEF "Health Impacts of Coal-Derived Substances in Drinking Water" The health effects of coal combustion are well known; however, much less is known about the potential impact of ingesting toxins leached from coal into drinking water.  The author will discuss research in the Balkans and high rates of kidney and pelvic cancers found in U.S. states that have low rank coal deposits and rural populations using groundwater. Presenter: William H. Orem, USGS Sunday, Oct. 5, 8:45 a.m., Room 330B Water Census "Back to the Future-Basic Training" While training for a return to the moon, astronauts have provided insight on water availability here on Earth.  To prepare for future moon exploration, newly recruited astronauts spend a week in northern New Mexico learning basic field techniques in geology and geophysics.  Since 2004, USGS has been involved in the instruction of such field methods.  As part of their training, astronaut teams have collectively acquired gravity and magnetic data in the Taos Valley.  The data collection also helps map buried structures that influence ground-water flow and accumulation.  Thus, astronaut candidates learned lunar exploration techniques while at the same time providing insights into the availability of fresh water for residents of this dry area. Presenter: Patricia Dickerson, University of Texas at Austin Tuesday, Oct. 7, 10:45 a.m., Room 310D "Water Quality in Selected United States Aquifers, 1993-2005" The USGS collected 1,048 samples from wells and springs in 12 aquifer systems across the US including the Basin and Range, Biscayne, Castle Hayne, Edwards-Trinity, Floridan, Ozark Plateaus, Piedmont and Blue Ridge, Prairie du Chien, and Valley and Ridge.  Pesticides, volatile organic compounds, and nutrients were among the constituents analyzed. Water quality was highly variable.  The author will describe what was detected, and the land use and aquifer characteristics that result in higher contamination. Presenter: Bruce D. Lindsey, USGS Sunday, Oct. 5, 1:30 p.m., Room 342BE
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.

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