
	Where results make sense

Topic: Manson crater

Related Topics

Meteor Crater

Impact crater

Haughton impact crater

Lonar crater

Barringer Crater

Manson, Iowa

Chesapeake Bay impact crater

Chicxulub Crater

Ramon Crater

Bedout

Wanapitei crater

Crater

Noerdlinger Ries

Carolina bay

Lake Siljan

In the News (Mon 7 Dec 09)

Northern Trust

Marvin Harrison

Peter Chernin

Gary Locke

Match Play

Penelope Cruz

Mickey Rourke

AR Rahman

Danny Boyle

Hugh Jackman

	Manson, Iowa - Wikipedia, the free encyclopedia
		Manson is a city in Calhoun County, Iowa, United States.
		Manson is located near the site of Manson crater, formed by a meteorite collision that happened 74 million years ago.
		The crater's existence was first discovered during an oil-drilling wildcatting expedition in the 1930's.
	en.wikipedia.org /wiki/Manson,_Iowa (400 words)

	Manson crater - Wikipedia, the free encyclopedia
		The Manson impact crater is located near the site of Manson, Iowa where a meteorite landed during the Cretaceous Period, 74 million years ago.
		It was one of the biggest impacts by an object from outer space to happen in North America and was previously thought to have led to the extinction of the dinosaurs until age dating tests proved that it was too old.
		In 1991 and 1992 the Iowa Geological Survey along with the USGS conducted detailed research in part to test the possible connection of the Manson Crater with the K-T boundary extinction event.
	en.wikipedia.org /wiki/Manson_crater (372 words)

	About Manson, Iowa
		Manson lies near the center of a 24 mile wide crater that was created 74 million years ago when a meteorite crashed to earth.
		Manson's annual celebration is called "Greater Crater Days" in honor of the much-studied yet invisible crater.
		Manson Community Cares is a free time recreation group providing fun and a substance free environment for all ages throughout the Manson Northwest Webster District.
	www.mansoniowa.org /about.htm (312 words)

	Age of the Manson Impact Crater
		Manson ejecta is now clearly identified within the Pierre Shale (Crow Creek Member) of South Dakota and Nebraska.
		Manson is now one of the best known large impact structures on earth.
		First, Manson ejecta in the Crow Creek Member (Pierre Shale) occurs within strata that are constrained to the E. jenneyi or D. stevensoni marine ammonite zones (see Izett et al., 93, and subsequent publications) [it could be as high as the lower D. cheyennense zone].
	www.dinosauria.com /jdp/impact/manson.htm (1020 words)

	Remote Sensing @ CES (Site not responding. Last check: 2007-10-13)
		Consider one capable of producing a 50 km (31 mi) wide crater, excavated to a depth of 5 km (3 mi): the energy expended is thousands of times greater than the simultaneous detonation at one point of all the nuclear explosive devices (euphemism for bombs) manufactured to date.
		Slightly larger is the Chicxulub crater in the Mexican Yucatan, reputed to be evidence for the catastrophic impact event that hastened the demise of the remaining dinosaurs (many families and types had already diminished or reached extinction before this event).
		Manson material has been found in a thin layer at sites in South Dakota, up to 500 km (311 mi) away and the finest sizes traveled in the stratosphere probably well beyond North America (likely global in extent).
	ces.iisc.ernet.in /hpg/envis/Remote/section182.htm (2243 words)

	THE MANSON IMPACT STRUCTURE
		The Manson Impact Structure, named for the town of Manson near the center of the structure in north-central Iowa, has a diameter of 37 km (23 miles) making it the largest intact, on-shore meteorite crater in the United States.
		The area of the Manson Structure has been known as a region of anomalous geology since 1912, when samples collected during the drilling of a town water well at Manson proved to be unlike other rocks in the area.
		Study of the cores and other data showed the Manson Impact Structure to be a very well-preserved complex impact structure, with a large central peak, an outer ring of down-dropped strata known as the terrace terrane, and an intermediate crater moat region (cross-section).
	www.igsb.uiowa.edu /browse/manson/manson.htm (567 words)

	World and I Magazine - Massive Meteorites in Geological History
		Craters are the dominant feature on the surface of the moon, because cratering is virtually the only process that operates there.
		The Manson Crater of northwestern Iowa is the right age, and several others may be, but they are all much too small.
		It very likely outlines the western half of the crater basin that formed as the initial crater collapsed after the impact of 65 million years ago; and if so, the eastern half of the outline is hidden beneath the flood basalt flows of the Deccan Plateau.
	www.worldandi.com /public/1990/august/ns3.cfm (3180 words)

	UHAUL Supergraphics . Iowa
		The Manson impact structure appears at the bedrock surface, but there is no visual evidence of the crater on the surface land because it is concealed under 70 - 300 feet of glacial till.
		The central peak is the mound of rock found at the center of the crater.
		Surrounding the central peak is an area known as the crater moat.
	www.uhaul.com /supergraphics/crater/geologic-features.html (201 words)

	Christian KÖBERL - Drilling at the Bosumtwi meteorite impact crater, Ghana
		All craters have an outer rim and some crater infill (e.g., brecciated and/or fractured rocks, impact melt rocks), while the central structural uplift in complex craters consists of a central peak or of one or more peak ring(s) and exposes rocks that are uplifted from considerable depth.
		In general, simple craters have negative gravity anomalies due to the lower density of the brecciated rocks compared to the unbrecciated target rocks, whereas complex craters often have a positive gravity anomaly associated with the central uplift that is surrounded by an annular negative anomaly.
		Crater formation processes have been studied for many decades, but space limitations require that the reader is referred to the literature (see, e.g., Gault et al., 1968; Roddy et al., 1977; Melosh, 1989; and references therein) for a detailed discussion of the physical principles of impact crater formation.
	www.univie.ac.at /geochemistry/koeberl/impact (10305 words)

	crater — Infoplease.com
		Complex craters have a raised central peak surrounded by a trough and a fractured rim.
		Volcanic craters formed in these ways are relatively small, usually less than 1 mi (1.6 km) in diameter, and represent only a small fraction of the cone's diameter at the base.
		Craters of the Moon National Monument - Craters of the Moon National Monument, 53,440 acres (21,636 hectares), S central Idaho; est.
	www.infoplease.com /ce6/sci/A0813940.html (655 words)

	Boston Globe Online / Table of Contents
		Two US Geological Survey scientists have identified a 25- mile-wide crater in Iowa as the possible site where an asteroid or comet may have crashed into the Earth 65 million years ago, causing the extinction of dinosaurs.
		They believe that this suggests the impact was somewhere within 1,800 miles of the sites they studied in Montana and New Mexico, and led them to investigate a large crater near Manson, Iowa as the possible relic of the impact.
		Although geologists had thought the Iowa crater was much older, Pillmore and Izett used sophisticated new dating methods to find the age of the structure and determined that it was no more than 69 million years old, placing it in the right age bracket for the Alvarez impact.
	www.boston.com /globe/search/stories/nobel/1985/1985c.html (924 words)

	Manson
		Anderson, R.R. Hartung, J.B. 1991 The structural configuration of the Manson impact structure, Iowa, as interpreted from seismic data and confirmed by drill samples (abstract).
		Hartung, J.B. Kunk, M.J. and Anderson, R.R. 1990 Geology, geophysics, and geochronology of the Manson impact structure.
		Izett, G.A. Cobban, W.A., Obradovich, J.D. and Kunk, M.J. 1993 The Manson impact structure: 40Ar/39Ar age and its distal impact ejecta in the Pierre shale in southeastern South Dakota.
	www.unb.ca /passc/ImpactDatabase/images/manson.htm (2858 words)

	Features of an Impact Crater
		Simple craters are relatively small with a slightlly smaller depth than diameter (a 1:5 to 1:7 ratio) and a smooth bowl shape, usually filled with breccia.
		However, in large craters gravity causes the initially steep crater walls to collapse downward and inward, forming a complex structure with a central peak or peak ring, and a shallower depth compared to diameter (a 1:10 to 1:20 ratio).
		For example, the Manson Impact crater in America is 35 km in diameter and was caused by a bolide roughly 2 km in size.
	www.tiac.wa.gov.au /forum/2001/hocking/features.htm (582 words)

	Iowa's Manson Impact Structure
		Today there is no land surface expression of the crater that exists 100 to 300 feet below the town of Manson (Calhoun County), which lies near the center of the crater that bears its name.
		Since meteorite impact craters were almost unknown at that time, the feature was interpreted as a "cryptovolcanic structure," a crater produced by a giant explosion of volcanic gases.
		Although the Manson Impact Structure is now one of the best preserved and best studied complex impact craters on Earth, many unanswered questions remain about the effects of this impact on life forms.
	www.igsb.uiowa.edu /Browse/manson99/manson.htm (990 words)

	Demise of the Dinosaurs
		This crater is partially submerged in the Gulf of Mexico now and it was submerged in shallow seas at the time of the extinction.
		The crater near Manson was not found until people who were drilling for water found some unusually shattered rocks.
		The crater was buried during the last Ice Age, and there may be more craters waiting to be discovered.
	members.tripod.com /Melissa_Umlor/writings/dino.html (2252 words)

	The Chicxulub Impact Crater - Effects
		It is difficult to explain the size of the extinctions, and the volume and distribution of ejecta at the boundary, from this lesser impact.
		Whilst both craters were formed in a target rock of similar composition (sandstones and carbonates), the compositions of their melt rocks are very different (Fig.
		Considering their belief in an oblique impact from the southeast, Peter Shultz and colleagues (17) demonstrated that the resulting concentration of ejecta deposits in the northern hemisphere, and particularly the northwest interior of North America, led to greater extinction (and subsequent recovery) in these areas (Table 1).
	palaeo.gly.bris.ac.uk /communication/Hanks/eff.html (1963 words)

	Remote Sensing Tutorial Page 18-2
		In many respects, impact craters form in a similar manner to explosion craters where explosives are buried at some depth and then ignited.
		A series of panel cartoons, and accompanying descriptions, shows the sequence of formation of an impact crater (and is also described in the text).
		Having now grasped some idea of what happens when impact craters are produced, it could prove interesting to you to run your own calculations in determining Impact Cratering Effects.
	rst.gsfc.nasa.gov /Sect18/Sect18_2.html (2414 words)

	Just Can't Hide That Hometown Pride
		Manson's official slogan is "Celebrate Country Life," which won a controversial contest when my own entries, "Where Dreams Go to Die" and "Let the Ennui Consume You" were disqualified.
		Despite its sleepy exterior, however, Manson has the remarkable distinction of being the site of the largest natural disaster in American history--the only reason it isn't better known is that it happened 70-odd million years before any humans got around to living there.
		An interesting detail is that Manson has long drawn its water from a underground pocket that is basically the crater.
	www.ssc.wisc.edu /~jfreese/hometownpride.htm (678 words)

	Impact Cratering - Page 2
		Consider one capable of producing a (50 km) 30 mile wide crater, excavated to a depth of 5 km (3 miles): the energy involved is thousands of times greater than the simultaneous detonation at one point of all the nuclear explosive devices (euphemism for bombs) manufactured to date.
		At the instant of impact (0.0 sec), the target consisted of an average of 90 m (290 ft) of Mesozoic sedimentary rocks (mainly Cretaceous in age) (in green) overlain by as much as 52 m (170 ft) of young glacial till and underlain by 495 m (1600+ ft) of Paleozoic sedimentary rocks (light blue).
		Beyond the edges of the crater walls, rock units experience faulting and folding; especially along the upper walls, sedimentary (layered) rocks can be pealed back so that the layers may even be overturned.
	www.hwr.arizona.edu /nats101/CDs/trst/Sect18/nicktutor_18-2.html (1545 words)

	UHAUL Supergraphics . Iowa
		Due to the crater’s thick covering of Phanerozoic clast breccia, only small areas of the central peak and terrace terrane eroded.
		The Manson area was covered by several continental glaciers during the last 2.5 million years, causing further erosion and burying the region in layers of glacial till.
		Although groundwater is difficult to find within the Manson Crater, the structure has brought several benefits to local residents.
	www.uhaul.com /supergraphics/crater/effects2.html (216 words)

	[No title]
		So, in complex lunar craters, the blast pressure-wave as each "simple crater" is formed, quenches that discharge and the impinging current filament moves on to form the next crater, in a circular pattern.
		It would also be expected that the density of filaments would be lower at the periphery of the discharge Lunar craters, like the 93km Copernicus, show the precise characteristics to be expected from the inward collapse of the cratering "rope" and its lower peripheral density, which results in terracing of the crater walls.
		In a large crater, the fraction of the blasts directed radially inwards, if reasonably symmetrical and synchronous, would create an axial over-pressure, tending to quench any filaments attempting to discharge near the centre of the crater.
	www.kronia.com /thoth/thoth04.txt (3557 words)

	h24 The Chicxulub bolide crater
		At the beginning of the search, that the impact crater could be found had at least a chance of 8 to 5.
		And, debate as to the origin of the iridium anomaly was soon to cease: In Haiti, the terminal sediment layer of the Cretaceous contains, mixed together the iridium anomaly and irrefutable evidence for a bolide: abundant shock-metamorphosed quartz grains, and tektites.
		The impact crater has been given the name Chicxulub which is that of the nearby town and the locality (trivia: Chicxulub means, in translation from the dialect, "the tail of the devil").
	www.geowords.com /histbooknetscape/h24.htm (1120 words)

	Manson Impact Crater Tsunami Material (Site not responding. Last check: 2007-10-13)
		The largest intact asteroid impact crater in the U.S. lies completely buried under the verdant cornfields of north-central Iowa, near a town called MANSON.
		The crater is about 23 miles in diameter, making it about 30 TIMES larger than Meteor Crater in Arizona.
		Because the crater itself is completely buried and there is none of the impact rock available at the surface, the Crow Creek fragments are the ONLY AVAILABLE remnant of this Earth-rattling event.
	www.sciencemall-usa.com /mantsunmat.html (232 words)

	Looking For The Smoking Gun
		The absence of a smoking gun (a sufficiently large terrestrial crater with an age of 65 million years) has allowed volcanists to deny the cosmic catastrophists a complete victory.
		The Manson crater in Iowa (now buried) is of the right age but too small.
		The Chicxulub crater is discernible on gravity- and magneticanomaly maps and is probably of the right age.
	www.science-frontiers.com /sf075/sf075g09.htm (365 words)

	The Triassic-Jurassic extinction event - Bad Astronomy and Universe Today Forum
		They have not found the crater itself, but they believe the meteor may have hit what is now St George’s Channel, between Pembrokeshire and the Irish coast.
		The crater may have been more than 30 miles wide but would now be deeply buried beneath the sea floor.
		For example, Kara-Kul crater in Tajikistan formed less than 5 million years ago and is larger, 52 km in diameter.
	www.bautforum.com /showthread.php?p=841908 (1388 words)

	SIGHTINGS
		In the continental United States, only the crater left by a meteorite 35 million years ago at Chesapeake Bay is larger than the Manson Impact, according to Peter Schultz, a geology professor at Brown University.
		At Manson, Anderson theorizes the meteorite was traveling at 60,000 mph when it hit.
		The impact was about 3 1/2 miles deep, and as it bore into the earth, the sides of the crater were lifted 1 1/2 miles high from the earth's surface.
	www.rense.com /ufo/iowameteor.htm (532 words)

	Dinosaur Extinctions: No Asteroid or Comet Impact Here
		Also, the structural similarities of multi-ringed craters with a central peak are too uniform, regardless of size and proposed angle of impact, for them to be impact craters; laboratory experiments show different structures for different angles and impactor size.
		Iridium (terrestrial iridium, microtektites or tektites) is ejected as the by-products of hydrogen fusion are released.
		For one, Chicxulub crater probably did not coincide with the boundary that marks the mass extinction (K/T boundary), and the object was smaller than theorized (120 kilometers in diameter, not the proposed 180 to 300 km) with a date about 300,000 years prior to the boundary.
	www.livingcosmos.com /k-t.htm (12337 words)

	[No title]
		However, a suitable crater of the right age and magnitude to trigger the K-T extinctions has not been located.
		However, Cisowski (1988; personal communication, 1989) notes that the Manson structure is in a normal magnetic polarity chron, whereas the K-T boundary is in a reversed polarity chron (R29).
		The Manson structure--if it is an impact event--was too small to have triggered an impact winter.
	www.lycos.com /info/iridium.html (575 words)

	wetumpkawebpage
		Craters are the most common topographic form on planetary surfaces in the inner part of the solar system.
		Wetumpka's horseshoe-shaped crater rim and associated interior northeast-trending aeromagnetic anomaly are evidence of an oblique impact by a cosmic object arriving upon a low-angle, northeast-to-southwest trajectory.
		In assessing minimum age of Wetumpka's impact crater, an important fact is absence of the Arcola Limestone Member, uppermost member of the Mooreville Chalk, within the impact-crater melange and all grabens associated with the impact crater.
	www.auburn.edu /~kingdat/wetumpkawebpage3.htm (16296 words)

Try your search on: Qwika (all wikis)