Way back in July 1994, our solar system
was visited by a ‘string of pearls’ known as the Shoemaker-Levy 9 comet,
this asterism stuck Jupiter with the force of
thousands of our largest nuclear bombs and did it some 13 times in
the interval of several days. Since Jupiter is
composed mainly of gases there were just a remnant ‘black eyes’ left
behind in its atmosphere, and these disappeared
completely after several weeks.
Fig 1: Post impacts, polar orthographic mosaic of Jupiter in 2.0 micron
infrared...
by the 5-m Hale Telescope at Mt. Palomar, July
1994 (Cornell University/Caltech/Air & Space Museum).
But, when this happens on Earth millions
of tons of rock, dust & water are thrown up through the atmosphere
and
in the case of large (> 8KM) asteroids; matter
will even reach escape velocity. For the next several days that ejecta,
containing associated geochemical anomalies,
iridium, gold, rhenium, arsenic, antimony and selenium, rock dust, broken
or brecciated rocks, shocked quartz, impactites
or impact glass such as tektites, coesite, stishovite, a higher pressure
polymorph of quartz, meteoric oxides and water
will rain down upon the planet depositing a world-wide dust layer.
In the K-T event this was anywhere from a meter
to a centimeter thick layer, depending how far it was away from
the Chicxulub crater. The following months
most vegetation will have died and a nuclear winter could last for several
years.
This multiple event may have happened to
earth. In 1980, a physicist Luis Alvarez and his geologist son Walter Alvarez,
suggested that the K-T event, the extinction
of the dinosaurs and up to 80% of the other species, some 65 million years
ago may be due to the impact of the Chicxulub
asteroid. That occurrence is pretty much accepted nowadays. Around
this time there were also several other very
large craters produced.
The Boltysh Crater in the Ukraine and & the
Silverpit Crater off the eastern coast of England. Aged by radioactive
40Ar/39Ar decay products the Boltysh crater yielded
an age of 65.17±0.64 million years,
almost exactly the age of
Chicxulub crater in the Yucatan. All three
of these craters exhibit impact glasses and ejecta of breccia.
Fig 2: Location of the 24 Km Boltysh
Crater in the Ukraine,
...near Kiev was discovered during oil prospecting.
This type of event has occurred several
times and there are at least 5 major ‘mass extinction events’ recorded
in
Earth's geologic history. Some scientists forecast
that we are overdue for another visit from space. Besides the
obvious destruction of organic life there are
major geological events that occur and mark these event for 100’s of
millions of years, if you are wise enough to
read the signs.
Fig 3: Outcrop of strata crossing the Cretaceous-Tertiary
(K/T)
...boundary at Brazos River, Falls County, Texas;
note pick and shovel for scale. By Alan Hildebrand, Geological
Survey of Canada 1992.
An event such as this leaves evidence of
shock metamorphism, which is manifested in the presence of shattercones,
circular structures with raised rims, an area
of central uplift and sometimes a peak in the center.
A recently well studied crater at the
mouth of the Chesapeake Bay, from only 35.5 million years ago was
found to have crushed together the water tables
in area and faulted rock all the way down to the layer of
undifferentiated crystalline basement rock over
a kilometer deep.
Fig 4: Location of the Chesapeake Crater and it's multiple faults,
by Wylie Hoag, Ph. D.
The Yucatan or Chicxulub Crater, located
on the northwest coast of Yucatan, was discovered some 15 years ago and
determined that a 10-15-km object hit earth.
The Chicxulub melt-rock is dated by 40Ar/39Ar ½ life at 65.07 +-0.1
Ma
and impactor created a 180 km crater. Exhibiting
rock types of limestone, anhydrite (a calcium sulfate mineral),
a polymict breccia consisting of igneous-textured
microcrystalline clasts with shocked quartz xenoliths, and vesicular
and ropy textured phyllosilicate clasts, which
look like altered fragments of glass, both produced by shock melting.
Fig 5: A 0.32mm shocked quartz grain
from intracrater breccia sample Y6 N14
... of the Chicxulub crater
Located ~50 km from the crater's
center and penetrated ~500 meters of impact melt and breccias at its base.
Impact is the only natural process known to produce
shock waves of sufficient strength to cause deformation of
this type. (Taken in cross-polarized light by
Alan Hildebrand). The breccia contains clasts of sedimentary carbonates,
evaporites, recrystallized sandstone, granitic
gneisses and mica schists in a carbonate-rich matrix.
Other minerals found in meteorites
Metallic Iron
Metallic iron minerals make up the largest percentage
of iron meteorites and stony iron meteorites & chondrites.
Kamacite--this is essentially metallic iron with
up to 7.5% nickel
Taenite--this is iron with more than 25 percent
nickel
Plessite--this is not a mineral, but is a mixture
of fine-grained kamacite and taenite.
Iron Sulfides
Troilite--FeS--Iron sulfide similar to the earthly
mineral pyrrhotite.
Daubreelite--Fe++Cr2S4--
(Canyon Diablo), Cosby's Creek, Toluca, Cranbourne, and Mundrabilla (Mindat.org)
Iron Carbides
Cohenite--(Fe,Ni,Co)3C--is iron carbonate
Haxonite--(Fe,Ni,Co)23C6--is
a cubic iron carbide
Phosphides-- compound of P with a less
electronegative element(s)
Schreibersite and Rhabdite--(Fe,Ni)3P--Iron-nickel
phosphide
Oxides
Chromite--FeCrO4--This ore of chrome
Magnetite--Fe3O4--A common ore of iron
Corundum--Al2O3--same mineral as rubies &
sapphires
Carbons
Graphite--C--The common mineral of pencil lead
Diamond--C-- high temperature and pressure of
meteorite impact,
sometimes form diamonds. Canyon Diablo meteorites
have some.
Lonsdaleite--C--A hexagonal polymorph of diamond
(diamond is cubic).
Silicate Minerals
Pyroxenes-- found particularly chondrites and
achondrites. The following gradually decreases in magnesium and increases
iron content:
Enstatite-- Mg2Si2O6--The end member--the one
highest in magnesium.
Bronzite-- (Mg,Fe)SiO3--more iron than enstatite
and more magnesium than hypersthene.
Hypersthene-- (Mg,Fe)SiO3--mineral similar to
bronzite in many ways, but having more iron
Orthoferrosilite--FeSiO3--This is the other orthopyroxene
end member. It has the most iron and the least magnesium.
Clinopyroxenes-- (monoclinic crystal structure)
diopside (CaMg(SiO3)2), hedenbergite (CaFeSi2O6), augite ((Ca,Na)(Mg,Fe,Al)(Si,Al)2O6)
and pigeonite ((Mg,Fe,Al)(Mg,Fe)Si2O6) are also found in meteorites particularly
achondrites.
Olivine-- (Mg,Fe)2SiO4--formed at great depth,
the Earth's mantle may have significant olivine. in some pallasites with
forsterite
containing the most magnesium and fayalite having the most iron.
Feldspars--calcium, sodium. aluminum silicates
Phylosilicates-- or clays are found in some meteorites.
************************************************************************
Minerals
of the Canyon Diablo
The mineralogy of Canyon Diablo meteorites depends
on whether they have been shocked by impact.
While all of the specimens were shocked to some
degree, some specimens found around the crater
rim show very different mineralogy. The less
altered mineralogy is typical of iron meteorites.
The important minerals are:
Kamacite--this iron nickel alloy makes
about 90 percent of specimens.
Taenite--the other iron nickel constituents
taentie and plessite make up 1 to 4 percent of the material.
Schreibersite-- crystals occur as skeletal
blades. This is a very hard mineral that will ruin a saw blade
unfortunate enough to be put to the task of cutting a Canyon Diablo.
Troilite--this iron sulfide occurs as
nodules up to 50 mm across or as elongated lenses. Troilite may be
mixed with graphite, daubreelite, chromite, or base metal sulfides. Troilite-graphite
masses may make
up about 8.5 % of specimens.
Graphite-- occurs as large bodies within
iron or in separate masses.
Cohenite-- an iron carbide, is common.
This mineral is even harder than Schreibersite.
Haxonite-- chromite and silicates are
also found.
The specimens that were subjected to greater shock
show partial melting, recrystallization, neumann banding
and other deformation. Perhaps the most well-known
shock effect is the transformation of graphite to diamond
and lonsdaleite. These take the from of tiny
dark masses that become evident on sawing. A diamond blade will
move aside when it hits one of these.
Millerite is one of several minerals that is routinely
found (albeit in scarce quantities) within iron-nickel meteorites.
*******************************************************************************************************
Fig.6 Meteorite Market
Albareto L4 Chondrite | Bilanga, Achondrite (diogenite) | Clovis #2 L6 Chondrite | Dar al Gani 749 CO3 | El Kachla Impact melted chondrite | Gold Basin, Chondrite (L4) | Juvinas Eucrite achondrite | Monze L6 Chondrite | NWA 801 CR2 Chondrite | Plainview H5 Chondrite | Sikhote-Alin, Iron Individuals(Ogg) | Thuathe H4/5 Chondrite |
Alfianello L6 Chondrite | Boguslavka Hexahedrite | Dalgety Downs , Chondrite (L4 | Dar al Gani 779 Howardite Achondrite | Estherville Mesosiderite | Gujba Bencubbinite | Kabo H4 Chondrite | Mt. Egerton aubrite achondrite | NWA 869 Brecciated Chondrite | Portales Valley H6 Chondrite | Steinbach IVA Iron | Toluca IAB Iron |
Allende, Chondrite (CV3) | Boxhole IIIAB Iron | Dar al Gani 319 Polymict Ureilite | Dhofar 018 Howardite Achondrite | Etter, Chondrite (H6) | HaH237 CH Chondrite | Kilabo LL6 | Mundrabilla, Iron (Of, IRAN) | NWA 987 L3.8 Chondrite | Pultusk H5 Chondrite | Suizhou L6 Chondrite | Tsarev H5 Chondrite |
Barwise H5 Chondrite | Brenham Pallasite | Dar al Gani 380 Eucrite achondrite | Dhofar 125 Acapulcoite achondrite | Floyd L4 Chondrite | Hardtner L6 Chondrite | Korra Korrabes H3 Chondrite | Murchison, Chondrite (CM2) | NWA 1068 Martian Basalt | Rammya H5 impact melt | Sutton H5 Chondrite | Udei Station, Silicated Iron |
Begaa LL3 Chondrite | Brahin Pallasite | Dar al Gani 391 Eucrite achondrite | Dhofar 132 Ureilite achondrite | Gao/Gueine H5 Chondrite | Henbury, Iron (Om) | Lone Star H4 Chondrite | Northbranch, Chondrite (H5) | NWA 1109 Eucrite achondrite | Sahara 97103, Enstatite Chondrite (EH3) | Tafassasset Brachinite-like achondrite | Uwet, Hexahedrite |
Bensour LL6 Chondrite | Bur-Abor, Iron (Om) | Dar al Gani 400 Lunar | Dhofar 207 H3.4/3.5 chondrite | Gao-Guenie (b) CR Carbonaceous Chondrite | Hope Creek LL6 Chondrite | Loop (a) L6 Chondrite | NWA 060 CK5 | NWA 1242 Mesosiderite | Sahara 99555, Angrite | Tagish Lake (CI2?) | Vaca Muerta Mesosiderite |
Béréba Eucrite achondrite | Campo del Cielo Iron (Og) | Dar al Gani 412 CK5 | Dimmitt, Chondrite (H4) | Ghubara, Chondrite (L5) | Hunter LL5 Chondrite | Mayfield H5 Chondrite | NWA 479 Lunar | NWA1465 C3 Chondrite | Saratov, Chondrite (L4) | Tambo Quemada IIIAB Iron | Wabar IIIAB Iron |
Canyon Diablo, Iron (Og) | Dar al Gani 475 H3.4 Chondrite | Dresden H5 Chondrite | Gibeon Iron (etched slices) | Igdi Eucrite | Miles iron with silicate | NWA 530 CR2 chondrite | NWA1882 Mesosiderite | SAU 005/008 (Martian Basalt) | Tatahouine, Achondrite (Diogenite) | Wellman (f) H3.5 Chondrite | |
Cape York, Iron (Om) | Dar al Gani 476 (Martian Basalt) | El Gouanem Ureilite Achondrite | Gibeon whole irons | Imilac, Pallasite | Millbillillie, Achondrite (Eucrite) | NWA 725 Acapulcoite achondrite | Odessa, Iron (Og) | Seymchan Pallasite IIE | Taza Plessitic Octahedrite | Yorktown H5 Chondrite | |
Chinga, Ataxite Iron | Dar al Gani 477 L6 Chondrite | El Hammami, Chondrite (H5) | Gobabeb H4 Chondrite | Jilin, Chondrite (H6) | Mont Dieu, Iron II Of | NWA 753 Rumuruti Chondrite | Park Forest L5 Chondrite | Sikhote-Alin, Iron Fragments (Ogg) | Tishomingo Ataxite | Zag, Morocco,
Chondrite |
Fig
7: Silverpit Crater, North Sea, East of England
Our next crater of interest is the Silverpit
Crater, 80 miles east of the Yorkshire, England coast in the North Sea.
While this crater lies on a chalk layer, again
the crater is manifested by the standard shock geology, cohesite or stishovite
presence, shattercones, raised rims or central
emergence, circular structure, broken brecciated rocks, impact glass or
impactites and meteorite oxides. Consider the
similarities of this far-side Lunar crater below.
Fig.8 Lunar crater Mare Orientale
This crater is 12 miles (20 km) wide, with
some 9-10 concentric rings stretching from the central peak out almost
10km.
The central bowl shaped crater is about 2 miles
(3 km) and buried under shale & sandstone sediment almost a kilometer
deep and at the bottom of a 130-foot-deep sea.
The impactor is estimated to have been a 7 million-ton, 120m-wide object
which struck the earth at 20km/s. Its location
was theoretically suggested by statistical prognostication. To further
prove
that craters with these characteristics are impact
origin regardless of the planet/moon they hit. Silverpit looks almost
exactly like the Lunar crater Mare Orientale
& the Valhalla crater on Jupiter's moon Callisto, there are similar
craters on
Europa, which are on NASA's website in public
domain.
Fig 9: Valhalla on Callisto
Notice the concentric rings on all three
of these craters. There is some debate about the impact origin of
the Silverpit
crater, cast by Christian Koeberl, a geochemist
at the University of Vienna in Austria, when he wrote in the journal Nature
that Silverpit may be a sinkhole depression caused
by salt withdrawal.
Back to Earth: Shiva Crater- India & Small Point - NE U.S. Atlantic Ocean
Sankar Chatterjee, the primary investigator,
a paleontologist at Texas Tech University in Lubbock, says The Shiva Complex
is a large 600 by 400 kilometers teardrop shaped
(because the impactor struck the Earth at a low angle) underwater crater,
off the western coast of India, and was made
by an enormous impactor measuring 40 kilometers across.
Fig 10: Diagram of Shiva impact area. Credit: Sankar Chatterjee.
From the synopsis of Chatterjee’s paper
he reinforces the theory that, "Evidence is accumulating that there were
multiple
impacts across the Cretaceous-Tertiary boundary
such as the Chicxulub crater in Mexico, Boltysh crater in Ukraine, Silverpit
crater in North Sea, and the Shiva crater offshore
western India."
Many of these structures are some of the
best hydrocarbon producing sites in the world. Shiva is one of them.
Its morphology is much the same as the
previous craters, concentric geophysical rings, a collapsed outer rim,
an underwater
central spire as high as Mount Everest, dated
as 65 million years old. The central uplift called, Bombay High, has veins
of
pseudotachylite (formed largely by frictional
melting along faults where rocks moved at or after an impact event) and
a core
of Neoproterozoic granite (938±13 Ma)
that rebounded upward for more than 5 km.
The age of the crater is inferred from
its a 500,000 mile2 brecciated lava Deccan Traps, which encase alkaline
igneous rock
spires, rich in Iridium. Paleocene sediments,
isotopic dating ejecta melt, the magnetic anomaly of the Carlsberg Ridge,
seismic
reflection, and structural and drill core data
all indicate the possible impact origin of the Shiva structure. Siderophile
("iron-loving")
elements & rock type are, iridium-rich alkaline
melt rocks, shocked quartz, Ni-rich spinels (MgAl2O4, Magnesium Aluminum
Oxide),
Ni-rich vesicular glass, sanidine, a polymorph
of Potassium Aluminum Silicate KAlSi3O8, spherules, fullerenes (C60-Buckyballs),
glass-altered smectites (refers to a family of
non-metallic clays primarily composed of hydrated sodium calcium aluminum
silicate,
bentonite), and tsunami deposits. And finally
the K-T clay boundary layer in India is one meter thick- the thickest in
the world.
At the time of the K-T extinction, India
was an island located over the Reunion hotspot. The impact was so intense
that it sheared
and deformed the lithospheric mantle across western
India, contributed to major plate reorganization in the northwestern Indian
Ocean. As well as displaced the Carlsberg Ridge
500-km, which initiated rifting between India and Seychelles Islands. The
oblique
impact may have generated spreading asymmetry,
possibly linked to the sudden northward acceleration of the Indian plate
in Early
Tertiary. Oil companies and the Indian government
control the site where Shiva is located, and access is extremely limited,
so far,
the Shiva crater is still a non-peer reviewed
hypothesis, but suggests some very tasty hypotheses.
Fig 11: Small Point, Maine, cropped
to the center of the Small Point Crater off Maine & Mass.
USGS Image
The Small Point Investigation is on a structure
off the coast of Maine. There is evidence implying a large impact crater
in the
Gulf of Maine. Its most probable age is K-T boundary,
but it lacks definitive ages from impact materials. Regional apatite-
Ca5(PO4)3(F,Cl,OH) fission track data, which
indicate a temperature above 110*C F and show a reheating event probably
beginning
in the late Cretaceous. The most distinctive
features of the Small Point crater are its topographic and magnetic expressions.
"Now researchers are looking at another location
off the coast of Maine, near Small Point, where there is evidence of another
impact. It could well be that the dinosaur killing
asteroid was not alone when it slammed into the Earth." (H)
Two scientists, Dominic Manzer, an engineer
from NASA, and Dallas Abbott from the Earth Observatory at Columbia University,
are in preliminary stages of looking at this
event. As yet they have not found strong evidence to support their theory.
Manzer
and Abbott presented their initial findings on
what they are calling the Small Point crater in 2004 at a regional meeting
of the
Geological Society of America in Halifax, Nova
Scotia.
The two were studying the magnetism of
the crust around the Gulf of Maine when they noticed an anomaly. They detected
a
very large, and as yet, unexplainable, difference
in the magnetism of the crust from the Gulf area from that of the surrounding
areas. Additionally, there is an arrangement
of ridges on land that channels rivers and streams in Maine and Massachusetts
along
arcs that might be ridges of the western part
of an eroded crater.
David Kring of the Lunar and Planetary
Laboratory at the University of Arizona is pessimistic and sees no conclusive
evident
of an impact. If Manzer and Abbott are
correct, this crater is larger than Chicxulub. They are trying to determine
the age
of the crater, but the erosional effects of ice
ages have erased much of that evidence. Slim though any evidence might
be,
Abbott is not giving up any time soon. Rather,
she intends to look further south in the Martha's Vineyard area off Cape
Cod.
There, she is hoping to find impact related rocks
of the right age that might have been deposited after the glaciers retreated.
Menzer believes the possible scenario of
the event 65 million years ago was that the asteroid or comet broke up
before
hitting Earth and pieces of the larger body slammed
down in a rapid fire line of craters. The two scientists will search for
evidence this summer, to prove it was an impact
event. Rock layers can then be used to age just when the impact happened.
(I)
The Chicxulub Crater
The image below displays a striking semicircular
alignment or Cenote Ring around southern hemisphere of the crater.
This was realized through information gathered
due to oil research drilling in the area by PEMEX geophysicists Antonio
Carmargo-Zanoguera and Glen Penfield.
There is a huge amount of information on the net for this site, so I will
not
elaborate deeply. An excellent new
poster from a very long Dutch evolution blog page, including new anthropological
fossils.
Fig 12: A gravity map of The Chicxulub crater in Yucatan, Mexico.
The white dots are Cenotes (Maya word dzonot)
or limestone sinkholes. Notice the highlighted semicircleat the southern
outer
ring of the crater. Further digs proved
that trees were flattened up to a 1000 km. away and the impact was partially
in a shallow
sea so there were tsunamis which radiated across
the Gulf of Mexico. Compare this to the 1908 Tunguska event where trees
were only flattened out to 40 - 45 km (2150km2).
And sent its shock wave TWICE around the world!
Tugunska Airburst- Siberia, Russia- June 30, 1908, 7:14 a.m. (DTT)
Fig. 13 Recent scare- but just a little small
...to cause a global extinction event,
but still what should be a major wake-up call to GEE's in the future.
A very recent (Oct.2010) ground penetrating
RADAR resurvey of the area by Vladimir Alexeev with Troitsk Innovation
and
Nuclear Research Institute (TRINITY) has
turned up a potential lake-filled crater (Lake Cheko- 60° 53' 09";
N, 101° 53' 40"; E,),
near the Kimchu River, for this impactor.
Although options are still mixed and undecided, there are only about the
a 'kajillion'
theories to the cause. Some more improbable,
than the adjective I just used.
If this hypothesis is discovered to be
probable or true, then it proves the object did hit the surface of the
Earth and it most
likely was not a 'ice and gravel' comet, but
a small asteroid, probably (I predict) stony, since small percentage
of particles
found in the area have been iron-nickel.
There has been some very extensive sampling
by researchers since the 1927 expedition. A 1994 paper by Italian
researchers,
Longo,
G.; Serra R., Cecchini S. and Galli M, searched 71 resin samples from
impacted Siberian Spruce trees and found 28
elements in the microremenants. HIgher
percentage of these are, Fe, Ca, Al, Si, Au, Cu, S, Zn, Cr, Ba, Ti, Ni,
C and O. Of the
some 7163 particles found, about 450 were Z>20,
(Fe=22) or ~6%. That composition could indicate it was a very common LL
or
L chondrite asteroid (my prediction),
and in a time range of only 1904-1910, with no volcanic particles during
these times and
a obvious peak at 1908, leading to the prediction
that the impactor was most likely a stony asteroid and not a comet.
***********************************
Conclusions
The best available data on these craters
(except Chesapeake) lump these events into a relatively short time frame
in geologic
terms about 100,000 -300,000 years. If further
research is done, it is found that there are at least 5 times in the past
multiple
major impactors have collided with the earth
and done global catastrophic damage, both to biodiversity and geological
structures.
This occurrence tends to dovetail an astrophysical
theory which states the solar system traveles through sparse & dense
areas
of local galactic spiral arms/branches. This
in effect causes perturbation of ‘comets’ in the Oort Belt and recently
discovered
Kuiper Belt, which contain estimated millions
of comet/asteroid sized bodies from the size of basketballs to large mountains.
After a million year trip past Jupiter, to
be possibly perturbated and torn apart like the Shoemaker-Levy 9 comet
(on it’s previous
pass near Jupiter before it collided with
the same planet in 1994) and inward to our Sun, there is a chance for them
to collide with
Earth. If an object is large enough it will
leave eon old evidence for geologists to discover. Current high demand
for hydrocarbon
based energy has oil companies world-wide
searching for particular structures which hold gas and oil. In each of
the K/T craters
discussed above, many of these conditions
are met and gas and oil are being successfully extracted.
Certainly in the form of global extinction
events, the effects of large impactors on humans has been negligible, so
far. But the
result of these collisions to the energy demands
of a growing populous of ever increasing complexity, could mean increased
discovery of energy resources. If exploration
companies would correlate their efforts in the area of the 180 or so large
impact
craters, along with their current exploration
projects using geological and magnetic mapping, field surveys and data
from Earth
Resource Satellites, further unknown craters
large enough to cause the aforementioned morphology and conducive to pooling
of
gas and oil, there is a potential for major
discoveries. If we can do it before the ‘next one’ hits.
******************************************************************************************
References:
Fig 1: Post-impacts,
polar orthographic mosaic of Jupiter in 2.0 micron infrared by the
5-m Hale Telescope at Mt. Palomar, July 1994
(Cornell University/Caltech/Air & Space Museum).
Fig 2: Wikipedia The 24Km Boltysh Crater in the Ukraine, near Kiev was discovered during oil prospecting.
Fig 3: Geological
Survey of Canada 1992 Outcrop of strata crossing the Cretaceous-
Tertiary (K/T) boundary at Brazos River, Falls
County, Texas By Alan Hildebrand,
Fig 4:
Chesapeake Bay Bolide homepage.
http://woodshole.er.usgs.gov/epubs/bolide/summary.html
Maintained by webmaster-woodshole@usgs.gov
Fig 5: A 0.32mm
shocked quartz grain from intracrater breccia sample Y6 N14 of the
Chicxulub crater located. (Taken in cross-polarized
light by Alan Hildebrand)
Fig 6: The Cambridge Encyclopedia of Meteorites- 2002 O. Richard Norton Meteorite Market
Fig 7: BBC
News Friday, 18 March, 2005, 12:05 GMT North Sea crater
shows its scars
By Jonathan Amos BBC News science reporter
Fig 8: Mare Orientale Credit: NASA, Lunar Orbiter 4 http://nssdc.gsfc.nasa.gov/planetary/lunar/lunarorb.html
Astronomy Picture
of the Day
2002 November 23
Looking like a target ring bull's-eye,
the Mare Orientale is one of the most striking large scale lunar features.
Located
on the Moon's extreme western edge, this impact
basin is unfortunately difficult to see from an earthbound perspective.
It is over 3 billion years old, about 600 miles
across and was formed by the impact of an asteroid sized object. The collision
caused ripples in the lunar crust resulting in
the three concentric circular features visible in this 1967 photograph
made by
NASA's Lunar Orbiter 4. Molten lava from the
Moon's interior flooded the impact site through the fractured crust creating
a mare.
Fig 9: Valhalla
Carter on Callisto From Voyager Taken: 1979-03-06
http://nssdc.gsfc.nasa.gov/imgcat/html/object_page/vg1_p21287.html
Fig 10: 2003
Seattle Annual Meeting (November 2–5, 2003) Paper No. 60-8
Presentation Time: 9:45 AM-10:00 AM
THE SHIVA CRATER: IMPLICATIONS FOR DECCAN VOLCANISM,
INDIA-SEYCHELLES RIFTING, DINOSAUR EXTINCTION,
AND PETROLEUM ENTRAPMENT AT THE KT BOUNDARY
CHATTERJEE, Sankar(1), BOUNDARY GUVEN, Necip2,
YOSHINOBU, Aaaron(2), and DONOFRIO, Richard (3),
(1) Geosciences, Texas Tech Univ, MS Box 41053,
Lubbock, TX 79409-3191, sankar.chatterjee@ttu.edu,
(2) Department of Geosciences, Texas Tech Univ,
Lubbock, TX 79409-1053,
(3) Exploration and Development Geosciences,
University of Oklahoma, Norman, OK 73069
Fig 12: Geological
Survey of Canada. The Chicxulub crater in Yucatan, with highlighted semicircle
of Cenotes or limestone sinkhole which border
the southern outer ring of the crater.
Fig 11: The
Magnetic Field over Small Point, Maine
http://svs.gsfc.nasa.gov/vis/a000000/a002700/a002723/index.html
Possible Second Crater Linked to Dinosaur Extinction
http://starryskies.com/articles/2003/04/impact.html
From NASA Scientific Vis. Studio: Copyright ©
1995 - 2004
Submit a comment or teaching tip North
American Magnetic Anomaly
Group (NAMAG) scale 1:5000
compilation and geologic mapping
applications of the new digital magnetic anomaly
database and map
of North America Geol. Soc. Am.
Kathy Miles, Author, and Chuck Peters, Systems
Administrator
k_miles+c_peters@200412.starryskies.net
Fig. 13
The direction of imapct by the Tungunska 'Bolide' of 1908 (text embedded
in image)
Russian
2010 article Scientific American
2008
article (8 page .pdf)
F: http://pangea.stanford.edu/research/noble/newidria/node4.html
G: DEEP
IMPACT Shiva: Another K-T Impact?
http://www.spacedaily.com/news/deepimpact-04r.html
by Leslie Mullen for Astrobiology Magazine
Moffett Field CA (SPX) Nov 04, 2004
H: Possible
Second Crater Linked to Dinosaur Extinction
http://starryskies.com/articles/2003/04/impact.html
I: Kathy Miles,
Author, and Chuck Peters, Systems Administrator
http://svs.gsfc.nasa.gov/vis/a000000/a002700/a002723/index.html
k_miles+c_peters@200412.starryskies.net
More
Asteroid Info? .
.