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58-812: The Mascarene Basin is bounded on the west by the island of Madagascar, i.e. the Precambrian Madagascar Massif. It is separated from the Western and Eastern Somali Basins to the north and northeast by the island arc from the northern tip of Madagascar, the Farquhar Islands , the Amirante Islands and Amirante Plateau, the Seychelles Plateau and the Mascarene Plateau . To the southwest and south it

116-708: A supereon , but this is also an informal term, not defined by the ICS in its chronostratigraphic guide. Eozoic (from eo- "earliest") was a synonym for pre-Cambrian , or more specifically Archean . A specific date for the origin of life has not been determined. Carbon found in 3.8 billion-year-old rocks (Archean Eon) from islands off western Greenland may be of organic origin. Well-preserved microscopic fossils of bacteria older than 3.46 billion years have been found in Western Australia . Probable fossils 100 million years older have been found in

174-593: A federal survey agency, in part to inventory the vast lands added to the United States by the Louisiana Purchase in 1803 and the Mexican–American War in 1848. The USGS was authorized on March 3 in a last-minute amendment to an unrelated bill that charged the new agency with the "classification of the public lands, and examination of the geological structure, mineral resources, and products of

232-449: A lack of accuracy and detail in comparison to older generation maps based on aerial photo surveys and field checks. As the digital databases were not designed for producing general-purpose maps, data integration can be a problem when retrieved from sources with different resolutions and collection dates. Human-made features once recorded by direct field observation are not in any public domain national database and are frequently omitted from

290-677: A new way to view their entire digitized collection of over 178,000 maps from 1884 to 2006. The site is an interactive map of the United States that allows users to search or move around the map to find the USGS collection of maps for a specific area. Users may then view the maps in great detail and download them if desired. In 2008 the USGS abandoned traditional methods of surveying, revising, and updating topographic maps based on aerial photography and field checks. Today's U.S. Topo quadrangle (1:24,000) maps are mass-produced, using automated and semiautomated processes, with cartographic content supplied from

348-410: A non-metric scale virtually unique to the United States. Each of these maps covers an area bounded by two lines of latitude and two lines of longitude spaced 7.5 minutes apart. Nearly 57,000 individual maps in this series cover the 48 contiguous states , Hawaii , U.S. territories , and areas of Alaska near Anchorage , Fairbanks , and Prudhoe Bay . The area covered by each map varies with

406-528: A number of specific science programs, facilities, and other organizational units: The Earthquake Hazards Program monitors earthquake activity worldwide. The National Earthquake Information Center (NEIC) in Golden, Colorado , on the campus of the Colorado School of Mines detects the location and magnitude of global earthquakes. The USGS also runs or supports several regional monitoring networks in

464-846: A number of water-related programs, notably the National Streamflow Information Program and National Water-Quality Assessment Program. USGS Water data is publicly available from their National Water Information System database. The USGS also operates the National Wildlife Health Center , whose mission is "to serve the nation and its natural resources by providing sound science and technical support, and to disseminate information to promote science-based decisions affecting wildlife and ecosystem health. The NWHC provides information, technical assistance, research, education, and leadership on national and international wildlife health issues." It

522-735: A possible 2450 Ma red alga from the Kola Peninsula , 1650 Ma carbonaceous biosignatures in north China, the 1600 Ma Rafatazmia , and a possible 1047 Ma Bangiomorpha red alga from the Canadian Arctic. The earliest fossils widely accepted as complex multicellular organisms date from the Ediacaran Period. A very diverse collection of soft-bodied forms is found in a variety of locations worldwide and date to between 635 and 542 Ma. These are referred to as Ediacaran or Vendian biota . Hard-shelled creatures appeared toward

580-684: A result, some have noted that the U.S. Topo maps currently fall short of traditional topographic map presentation standards achieved in maps drawn from 1945 to 1992. The Hydrologic Instrumentation Facility (HIF) has four sections within its organizational structure; the Field Services Section which includes the warehouse, repair shop, and Engineering Unit; the Testing Section which includes the Hydraulic Laboratory, testing chambers, and Water Quality Laboratory;

638-399: A specific oceanic location or ocean current is a stub . You can help Misplaced Pages by expanding it . This tectonics article is a stub . You can help Misplaced Pages by expanding it . Precambrian The Precambrian ( / p r i ˈ k æ m b r i . ə n , - ˈ k eɪ m -/ pree- KAM -bree-ən, -⁠KAYM- ; or Pre-Cambrian , sometimes abbreviated pC , or Cryptozoic ) is

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696-478: A towing tank, jet tank, pipe flow facility, and tilting flume. In addition, the HIF provides training and technical support for the equipment it stocks. The Engineering Group seeks out new technology and designs for instrumentation that can work more efficiently, be more accurate, and or be produced at a lower cost than existing instrumentation. HIF works directly with vendors to help them produce products that will meet

754-644: A variety of USGS Report Series that include preliminary results, maps, data, and final results. A complete catalog of all USGS publications is available from the USGS Publications Warehouse. In the mid-1800s, various states set up geological survey institutions; e.g., the Kentucky Geological Survey , established in 1854. In 1879, a report from the National Academy of Sciences prompted Congress to set up

812-514: Is a partnership-driven program that teams scientific researchers with natural and cultural resource managers to help fish, wildlife, waters, and lands across the country adapt to climate change . The National CASC (NCASC), based at USGS headquarters in Reston, Virginia, serves as the national office for the CASC network, while eight regional CASCs made up of federal-university consortiums located across

870-752: Is headquartered in Reston, Virginia , with major offices near Lakewood, Colorado ; at the Denver Federal Center ; and in NASA Ames Research Park in California. In 2009, it employed about 8,670 people. The current motto of the USGS, in use since August 1997, is "science for a changing world". The agency's previous slogan, adopted on its hundredth anniversary, was "Earth Science in the Public Service". Since 2012,

928-664: Is known to occur during the RNA replication of extant coronaviruses . Evidence of the details of plate motions and other tectonic activity in the Precambrian is difficult to interpret. It is generally believed that small proto-continents existed before 4280 Ma, and that most of the Earth's landmasses collected into a single supercontinent around 1130 Ma. The supercontinent, known as Rodinia , broke up around 750 Ma. A number of glacial periods have been identified going as far back as

986-483: Is mapped at this scale in quadrangles measuring 1° by 1°. USGS topographic quadrangle maps are marked with grid lines and tics around the map collar which make it possible to identify locations on the map by several methods, including the graticule measurements of longitude and latitude, the township and section method within the Public Land Survey System , and cartesian coordinates in both

1044-642: Is separated from the Madagascar Basin by a continuation of the island arc through Mauritius Island and Reunion Island , the Mauritius Fracture Zone, a fracture zone trending approximately NE-SW, located east of Mauritius Island , and the northwestern edge of the Madagascar Ridge. The approximate center of the basin is 15°S 56°E  /  15°S 56°E  / -15; 56 . This article about

1102-529: Is the agency primarily responsible for surveillance of H5N1 avian influenza outbreaks in the United States. The USGS also runs 17 biological research centers in the United States, including the Patuxent Wildlife Research Center . The USGS is investigating collaboration with the social networking site Twitter to allow for more rapid construction of ShakeMaps. ShakeMaps are an interactive tool allowing users to visually observe

1160-521: Is thought that the Earth coalesced from material in orbit around the Sun at roughly 4,543 Ma, and may have been struck by another planet called Theia shortly after it formed, splitting off material that formed the Moon (see Giant-impact hypothesis ). A stable crust was apparently in place by 4,433 Ma, since zircon crystals from Western Australia have been dated at 4,404 ± 8 Ma. The term "Precambrian"

1218-582: Is thought to have formed about 1300-900 Ma, to have included most or all of Earth's continents and to have broken up into eight continents around 750–600 million years ago. United States Geological Survey The United States Geological Survey ( USGS ), founded as the Geological Survey , is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology , geography , geology , and hydrology . The agency

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1276-731: Is used by geologists and paleontologists for general discussions not requiring a more specific eon name. However, both the United States Geological Survey and the International Commission on Stratigraphy regard the term as informal. Because the span of time falling under the Precambrian consists of three eons (the Hadean , the Archean , and the Proterozoic ), it is sometimes described as

1334-534: The Huronian epoch, roughly 2400–2100 Ma. One of the best studied is the Sturtian-Varangian glaciation, around 850–635 Ma, which may have brought glacial conditions all the way to the equator, resulting in a " Snowball Earth ". The atmosphere of the early Earth is not well understood. Most geologists believe it was composed primarily of nitrogen, carbon dioxide, and other relatively inert gases, and

1392-599: The State Plane Coordinate System and the Universal Transverse Mercator coordinate system . Other specialty maps have been produced by the USGS at a variety of scales. These include county maps, maps of special interest areas, such as the national parks , and areas of scientific interest. A number of Internet sites have made these maps available on the web for affordable commercial and professional use. Because works of

1450-634: The UCERF California earthquake forecast. As of 2005, the agency is working to create a National Volcano Early Warning System by improving the instrumentation monitoring the 169 volcanoes in U.S. territory and by establishing methods for measuring the relative threats posed at each site. The USGS also operates five volcano observatories throughout the nation: the Alaska Volcano Observatory in Anchorage, Alaska (on

1508-522: The geologic time scale . It spans from the formation of Earth about 4.6 billion years ago ( Ga ) to the beginning of the Cambrian Period, about 538.8 million years ago ( Ma ), when hard-shelled creatures first appeared in abundance. Relatively little is known about the Precambrian, despite it making up roughly seven-eighths of the Earth's history , and what is known has largely been discovered from

1566-570: The magnetic field at magnetic observatories and distributes magnetometer data in real time. The USGS collaborates with Canadian and Mexican government scientists, along with the Commission for Environmental Cooperation , to produce the North American Environmental Atlas , which is used to depict and track environmental issues for a continental perspective. The USGS operates the streamgaging network for

1624-482: The oxygen catastrophe . At first, oxygen would have quickly combined with other elements in Earth's crust, primarily iron, removing it from the atmosphere. After the supply of oxidizable surfaces ran out, oxygen would have begun to accumulate in the atmosphere, and the modern high-oxygen atmosphere would have developed. Evidence for this lies in older rocks that contain massive banded iron formations that were laid down as iron oxides. A terminology has evolved covering

1682-442: The 15-minute series, was once used to map the contiguous 48 states at a scale of 1:62,500 for maps covering the continental United States, but was discontinued during the last quarter of the twentieth century. Each map was bounded by two parallels and two meridians spaced 15 minutes apart—the same area covered by four maps in the 7.5-minute series. The 15-minute series, at a scale of 1:63,360 (one inch representing one mile), remains

1740-401: The 1960s onwards. The Precambrian fossil record is poorer than that of the succeeding Phanerozoic , and fossils from the Precambrian (e.g. stromatolites ) are of limited biostratigraphic use. This is because many Precambrian rocks have been heavily metamorphosed , obscuring their origins, while others have been destroyed by erosion, or remain deeply buried beneath Phanerozoic strata. It

1798-439: The 30 x 60-minute quadrangle series. Each of these quadrangles covers the area contained within 32 maps in the 7.5-minute series. The 1:100,000 scale series is unusual in that it primarily employs the metric system . One centimeter on the map represents one kilometer of distance on the ground. Contour intervals , spot elevations, and horizontal distances are also specified in meters. The final regular quadrangle series produced by

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1856-980: The Information Technology Section which includes computer support and the Drafting Unit; and the Administrative Section. The HIF was given national responsibility for the design, testing, evaluation, repair, calibration, warehousing, and distribution of hydrologic instrumentation. Distribution is accomplished by direct sales and through a rental program. The HIF supports data collection activities through centralized warehouse and laboratory facilities. The HIF warehouse provides hydrologic instruments, equipment, and supplies for USGS as well as Other Federal Agencies (OFA) and USGS Cooperators. The HIF also tests, evaluates, repairs, calibrates, and develops hydrologic equipment and instruments. The HIF Hydraulic Laboratory facilities include

1914-523: The National GIS Database. In the two years from June 2009 to May 2011, the USGS produced nearly 40,000 maps, more than 80 maps per work day. Only about two hours of interactive work are spent on each map, mostly on text placement and final inspection; there are essentially no field checks or field inspections to confirm map details. While much less expensive to compile and produce, the revised digital U.S. topo maps have been criticized for

1972-473: The U.S. government are in the public domain , it is also possible to find many of these maps for free at various locations on the Internet. Georeferenced map images are available from the USGS as digital raster graphics (DRGs) in addition to digital data sets based on USGS maps, notably digital line graphs (DLGs) and digital elevation models (DEMs). In 2015, the USGS unveiled the topoView website,

2030-726: The U.S., U.S. Pacific Islands, and U.S. Caribbean deliver science that addresses resource management priorities of the states within their footprints. Since 1962, the Astrogeology Research Program has been involved in global, lunar , and planetary exploration and mapping . In collaboration with Stanford University , the USGS also operates the USGS-Stanford Ion Microprobe Laboratory, a world-class analytical facility for U-(Th)-Pb geochronology and trace element analyses of minerals and other earth materials. USGS operates

2088-933: The USGS Center for Coastal Geology) has three sites, one for the Atlantic Ocean (located in Woods Hole, Massachusetts ), one for the Pacific Ocean (located in Santa Cruz, California ) and one for the Gulf of Mexico (located on the University of South Florida's St. Petersburg campus). The goal of this department is to conduct research in geology, mapping, hydrology, biology, and related sciences; evaluate hazards associated with floods, droughts, hurricanes, subsidence, human activity, and climate change; map

2146-474: The USGS is the 1:250,000 scale topographic series. Each of these quadrangles in the conterminous United States measures 1 degree of latitude by 2 degrees of longitude. This series was produced by the U.S.  Army Map Service in the 1950s, prior to the maps in the larger-scale series, and consists of 489 sheets, each covering an area ranging from 8,218 square miles (21,285 km ) at 30° north to 6,222 square miles (16,115 km ) at 49° north. Hawaii

2204-503: The USGS science focus has been directed at topical "Mission Areas" that have continued to evolve. Further organizational structure includes headquarters functions, geographic regions, science and support programs, science centers, labs, and other facilities. The USGS regional organization aligns with the U.S. Department of the Interior Unified Interior Regions: USGS operates and organizes within

2262-520: The USGS to rely on donations of time by civilian volunteers in an attempt to update its 7.5-minute topographic map series, and USGS stated outright in 2000 that the program was to be phased out in favor of The National Map (not to be confused with the National Atlas of the United States produced by the Department of the Interior , one of whose bureaus is USGS). An older series of maps,

2320-494: The United States under the umbrella of the Advanced National Seismic System (ANSS). The USGS informs authorities, emergency responders, the media, and the public, both domestic and worldwide, about significant earthquakes. It maintains long-term archives of earthquake data for scientific and engineering research. It also conducts and supports research on long-term seismic hazards . USGS has released

2378-912: The United States, with over 7400 streamgages . Real-time streamflow data are available online. As part of the Water Resources Research Act of 1984, the State Water Resources Research Act Program created a Water Resources Research Institute (WRRI) in each state, along with Washington DC, Puerto Rico, the US Virgin Islands, and Guam. Together, these institutes make up the National Institutes for Water Resources (NIWR). The institutes focus on water-related issues through research, training and collaboration. The National and regional Climate Adaptation Science Centers (CASCs)

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2436-1200: The campus of Alaska Pacific University ), the California Volcano Observatory in Menlo Park, California , the Cascades Volcano Observatory (covering volcanoes in Idaho , Oregon , and Washington ) in Vancouver, Washington , the Hawaiian Volcano Observatory in Hilo, Hawaii , and the Yellowstone Volcano Observatory (covering volcanoes in Arizona , Colorado , Montana , New Mexico , Utah , and Wyoming ) in Yellowstone National Park , Wyoming. The USGS Coastal and Marine Science Center (formerly

2494-422: The continental United States, though only for use by members of its defense forces). The next-smallest topographic series, in terms of scale, is the 1:100,000 series. These maps are bounded by two lines of longitude and two lines of latitude. However, in this series, the lines of latitude are spaced 30 minutes apart and the lines of longitude are spaced 60 minutes, which is the source of another name for these maps;

2552-401: The current scheme based upon numerical ages. Such a system could rely on events in the stratigraphic record and be demarcated by GSSPs . The Precambrian could be divided into five "natural" eons, characterized as follows: The movement of Earth's plates has caused the formation and break-up of continents over time, including occasional formation of a supercontinent containing most or all of

2610-420: The distribution and severity of Shaking resulting from Earthquakes. The USGS produces several national series of topographic maps which vary in scale and extent, with some wide gaps in coverage, notably the complete absence of 1:50,000 scale topographic maps or their equivalent. The largest (both in terms of scale and quantity) and best-known topographic series is the 7.5-minute, 1:24,000 scale, quadrangle ,

2668-665: The earliest part of Earth's history , set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian , the first period of the Phanerozoic Eon , which is named after Cambria , the Latinized name for Wales , where rocks from this age were first studied. The Precambrian accounts for 88% of the Earth's geologic time. The Precambrian is an informal unit of geologic time, subdivided into three eons ( Hadean , Archean , Proterozoic ) of

2726-453: The early years of the Earth's existence, as radiometric dating has allowed absolute dates to be assigned to specific formations and features. The Precambrian is divided into three eons: the Hadean (4567.3–4031 Ma), Archean (4031-2500 Ma) and Proterozoic (2500-538.8 Ma). See Timetable of the Precambrian . It has been proposed that the Precambrian should be divided into eons and eras that reflect stages of planetary evolution, rather than

2784-705: The end of that time span, marking the beginning of the Phanerozoic Eon. By the middle of the following Cambrian Period, a very diverse fauna is recorded in the Burgess Shale , including some which may represent stem groups of modern taxa. The increase in diversity of lifeforms during the early Cambrian is called the Cambrian explosion of life. While land seems to have been devoid of plants and animals, cyanobacteria and other microbes formed prokaryotic mats that covered terrestrial areas. Tracks from an animal with leg-like appendages have been found in what

2842-541: The landmass. The earliest known supercontinent was Vaalbara . It formed from proto-continents and was a supercontinent 3.636 billion years ago. Vaalbara broke up c. 2.845–2.803 Ga ago. The supercontinent Kenorland was formed c. 2.72 Ga ago and then broke sometime after 2.45–2.1 Ga into the proto-continent cratons called Laurentia , Baltica , Yilgarn craton and Kalahari . The supercontinent Columbia , or Nuna, formed 2.1–1.8 billion years ago and broke up about 1.3–1.2 billion years ago. The supercontinent Rodinia

2900-488: The latitude of its represented location due to convergence of the meridians. At lower latitudes, near 30° north, a 7.5-minute quadrangle contains an area of about 64 square miles (166 km ). At 49° north latitude, 49 square miles (127 km ) are contained within a quadrangle of that size. As a unique non-metric map scale, the 1:24,000 scale naturally requires a separate and specialized romer scale for plotting map positions. In recent years, budget constraints have forced

2958-545: The mission needs of the USGS. For instrument needs not currently met by a vendor, the Engineering Group designs, tests, and issues contracts to have HIF-designed equipment made. Sometimes HIF will patent a new design in the hope that instrument vendors will buy the rights and mass-produce the instrument at a lower cost to everyone. USGS researchers publish the results of their science in a variety of ways, including peer-reviewed scientific journals as well as in one of

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3016-465: The newest generation digital topo maps, including windmills, mines and mineshafts, water tanks, fence lines, survey marks, parks, recreational trails, buildings, boundaries, pipelines, telephone lines, power transmission lines, and even railroads. Additionally, the digital map's use of existing software may not properly integrate different feature classes or prioritize and organize text in areas of crowded features, obscuring important geographic details. As

3074-469: The onshore and offshore geologic framework; assess mineral resources and develop techniques for their discovery; assess water resources and develop an understanding of the impact of human activities and natural phenomena on hydrologic systems; assess links between biodiversity, habitat condition, ecosystem processes and health; and develop new technologies for collection and interpretation of earth science data. The USGS National Geomagnetism Program monitors

3132-428: The primary topographic quadrangle for the state of Alaska (and only for that particular state). Nearly 3,000 maps cover 97% of the state. The United States remains virtually the only developed country in the world without a standardized civilian topographic map series in the standard 1:25,000 or 1:50,000 metric scales, making coordination difficult in border regions (the U.S. military does issue 1:50,000 scale topo maps of

3190-526: The same area. However, there is evidence that life could have evolved over 4.280 billion years ago. There is a fairly solid record of bacterial life throughout the remainder (Proterozoic Eon) of the Precambrian. Complex multicellular organisms may have appeared as early as 2100 Ma. However, the interpretation of ancient fossils is problematic, and "... some definitions of multicellularity encompass everything from simple bacterial colonies to badgers." Other possible early complex multicellular organisms include

3248-403: Was founded on March 3, 1879, to study the landscape of the United States, its natural resources , and the natural hazards that threaten it. The agency also makes maps of extraterrestrial planets and moons based on data from U.S. space probes . The sole scientific agency of the U.S. Department of the Interior, USGS is a fact-finding research organization with no regulatory responsibility. It

3306-482: Was lacking in free oxygen . There is, however, evidence that an oxygen-rich atmosphere existed since the early Archean. At present, it is still believed that molecular oxygen was not a significant fraction of Earth's atmosphere until after photosynthetic life forms evolved and began to produce it in large quantities as a byproduct of their metabolism . This radical shift from a chemically inert to an oxidizing atmosphere caused an ecological crisis , sometimes called

3364-852: Was mud 551 million years ago. The RNA world hypothesis asserts that RNA evolved before coded proteins and DNA genomes. During the Hadean Eon (4,567–4,031 Ma) abundant geothermal microenvironments were present that may have had the potential to support the synthesis and replication of RNA and thus possibly the evolution of a primitive life form. It was shown that porous rock systems comprising heated air-water interfaces could allow ribozyme - catalyzed RNA replication of sense and antisense strands that could be followed by strand-dissociation, thus enabling combined synthesis, release and folding of active ribozymes. This primitive RNA replicative system also may have been able to undergo template strand switching during replication ( genetic recombination ) as

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