Earth - Craters

[bdw000]

Some experts here may find this tidbit interesting simply because these "impact craters" are only 4 to 8 thousand years old:

Serious journal article:
http://www.geologos.com.pl/geologos16/Geologos_16_1_Raukas_Stankowski.pdf

The following isn't much of an article, but has a couple of color pics:
http://io9.com/5556690/the-ancient-meteorite-cult-of-estonia

Crater sizes only from about 10 to 110 meters across.

[rhargett]

I'm probably bringing up something that has already been discussed at length - what is the probability that an impactor on any planetary body in our solar system will strike that body at or near 90 degrees? And what is the probability that multiple impactors over an arbitrary length of time of, perhaps 100 or 1000 years, would impact any planetary body at or near 90 degrees? I don't recall ever seeing a photo of a crater where I could immediately say the collision was oblique to the surface.

[redeye]

This has been discussed on a number of threads over the last few years. Here's a good overview:

The Craters Are Electric

Cheers!

[GaryN]

This image seems to clearly show what you mention. (Large Image)

http://hirise-pds.lpl.arizona.edu/PDS/E ... browse.jpg

There are round craters on the side of apparently steep slopes. Did the impactors come in sideways, and if not, then why aren't the craters at least elongated to some degree?
The image also shows features which look much more like an electrical arcing phenomena, as mentioned by seasmith here:

viewtopic.php?f=4&t=3521#p38029

[MattEU]

you might find this article interesting ... it seems to imply that crater sizes/ratios depend on G. it also mentions the statistical differences between simple and complex crater sizes.

does it show that the size/ratios of craters does not just depend on the thunderbolt from the gods but on the original physical property of the area being struck? or does the crater bolt change the material of the area so it does only depend on the type of thunderbolt?

and are craters caused by the thunderbolt itself, or, from discharges from the planet/object they are found on?

Simple craters are circular, bowl-shaped depressions with elevated rims and an approximately parabolic interior profile. They have no major internal topographic features.

One of the most important characteristics of impact craters is their ratio of rim-to-floor depth to the rim-to-rim diameter (d/D), which has a value of about 1:5 for most simple craters on the terrestrial planets as well as on the Moon. The upper rim of a simple crater often shows stratification and evidence of mass-wasting. Most lunar craters smaller than about 15 km in diameter are simple, while on Earth the upper limit is about 4 km.

The floor of simple craters is underlain by a breccia lens consisting of rock debris and shock-melted rock with a thickness of about half the rim-to-floor depth of the crater. This lens in turn lies in a bowl of fractured country rock. It is thought that the final shape of a simple crater is formed mainly by the gravitational collapse of the rim of the transient crater immediately after it forms.


Complex craters range in diameter from a few kilometers on Earth to a huge 460 km diameter crater observed on asteroid 4 Vesta. The 15 Ma Ries crater in Bavaria, which was visited during the last AGM in Munich, is one of the best known middle-sized complex craters on Earth, with a diameter of about 24 km.

Complex craters have a d/D ratio which varies widely fom 1:5 for small fresh complex craters to 1:150 for large craters, depending upon the planet. On Earth they exhibit central stuctural uplifts, rim synclines, and outer concentric zones of normal faulting. Extraterrestrial craters have been observed with multiple central peaks and terraced rims. The central uplift consists of strata which have been uplifted above the pre-impact level, and is surrounded by a ring depression (or rim syncline) filled with fragmented material and impact melt. The uplift of the transient cavity’s floor — accompanied by subsidence of the crater rim — is thought to be the main modification mechanism for complex craters.

The transition between simple and complex craters occurs over a narrow diameter range on a particular solar system body and is thought to scale as the inverse power of the surface gravity, g. The transition occurs around 15 km diameter on the Moon, 7 km on Mars and about 4 km on Earth. As the crater size increases further, the central peak complex in a complex crater begins to break up and form an inner ring of mountains. In large craters the ring is about half the rim-to-rim diameter, and these craters are called “peak-ring” craters.

However, not all of the complex crater features appear at the same diameter. Therefore the transition diameter is often expressed as the geometric mean, Dt, of several diameter values at which particular morphological features, such as central uplifts and terraced walls, appear. Studies on Martian craters indicate that the first complex features to appear are a flat floor, a central peak and a low d/D ratio.

Interestingly, the Dt values for Earth (3.1 km) and the Moon (18.7 km) differ by a factor of six, which is exactly the ratio of their values of g. In addition, complex craters on the Moon are on average six times deeper than on Earth.

Despite the importance of gravity, the lithology of the target area influences the value of Dt as well. This is best established for terrestrial craters of course, giving a simple-to-complex crater transition diameter of 2.25 km for sedimentary rocks and 4.75 km for crystalline rocks. It is thought that at least three (interrelated) target properties influence the shape of the final crater: rock strength, stratification and volatile content. An impact of a given energy will excavate a larger cavity in soft rocks, while there is evidence that complex craters develop more readily in stratified rocks.

The simple-to-complex transition coincides with a change in the texture of the ejecta surrounding fresh martian impact craters (this is of course more difficult to observe on Earth), indicating the mechanism of ejecta emplacement is dependent on crater size.

Craters less than 4 km in diameter show typical ballistic ejecta characteristics, while between 4 and 80 km emplacement seems to occur at least partly by surface flow, and larger craters again have ballistic ejecta emplacement. This might be explained by the incorporation of subsurface volatiles in the ejecta for impacts of intermediate size, while small impacts do not excavate deep enough to tap these volatiles, and large impacts completely vaporise them.

highlights from http://ougseurope.org/rockon/surface/impactcraters.asp

[GaryN]

A 'fresh' crater in Egypt.



http://news.nationalgeographic.com/news/2010/07/100722-science-space-egypt-kamil-crater-meteor-meteorite-impact-hazard

The claim is that an iron object reached the ground almost intact, but that they have collected thousands of fragments. Iron hits rock and shatters, does that sound right? I can think of another explanation for the crater and the fragments, but it probably belongs downstairs...

[MattEU]

Kamil Crater in Egypt and its ejecta rays

Kamil Crater in Egypt looks like a classic small EU crater with desert glass and even ejecta rays that are perhaps unique on earth although seen on other bodies in the solar system

Kamil Crater in Egypt EU formation or creation evidence

what is really interesting is that the egyptian Kamil Crater is located at the bottom of these 2 lines of hills with a sharp ridge on the top. are these electric discharge lines that were involved in the formation of the Kamil Crater?

Kamil Crater field in Egypt - secondary craters or discharge craters?

"near" the Kamil Crater is what appears to be a crater field located at 21°58'55.10"N 26°13'7.08"E (google earth). i guess that geology says they are extinct volcanoes. what makes a crater a crater and another crater an extinct volcano? if these are "impact craters" does anyone know the name of them?

there are more images and information about the Kamil Crater and the Kamil Crater field available here if you are interested (includes Kamil Crater egyptian desert glass)

[MattEU]

lake Kaali crater, Saaremaa island, Estonia - meteorite lake or electric universe event

the Kaali crater field on Saaremaa island in Estonia shows signs of being created by an electric universe event (EDM or discharge). from the sizes of the main Kaali crater and the smaller Kaali craters. it is said to have been formed by an iron meteorite and what is unusual about these iron meteorites is that the largest ones dont leave an impact crater. the smaller iron meteorite remains are either found in a small crater or scattered all over the countryside.

i would suggest that there is no iron meteorite impact but the iron is formed in the area it is found.


uplifted dolostone in the main Kaali crater at the Kaali crater field in Estonia

the Kaali craters have a funnel shape in the bottom (a couple do) and this would seem to be the discharge point and other remains of blasted and uplifted rock would suggest an EU creation.

are there any variations of the Kaali crater field found elsewhere in the world and do they have any evidence of Electric Universe origin and not impact craters?



hingham/deopham Mere and the Devils Punchbowl (thetford) in Norfolk

in Norfolk there are special oval or round lakes/ponds/depressions called Meres. England has a lot of Meres but these ones in Norfolk are special. Were they also caused by an EU event of EDM or a discharge?



crater field - Wretham Meres Norfolk

Wretham Meres are a very good example. There are a number of Meres at Wretham but there are also a lot of shrieking pits as they are called in Norfolk, which in an electric universe you could consider to be plasma arc pitting/cratering or a discharge of some type. is this an example of an electric universe crater field?

There is a suggestion that these were dug for iron. If they were created by digging for iron or had iron in them how did it get there and why in this specific spots?

although craters can be all size there seems to be a lot that are small and about the same size width (especially the slightly oval or tear drop shape ones). some have water in them and some are much deeper than others. are they created by the same process or are were different processes/events involved for each type and area?


you can read a lot more about the Kaali crater field and look at images of the main Kaali crater here

[GaryN]

Good work MattEU, on your web site. In the top image you posted here, the crater has a very hexagonal look, which can only mean one thing to me! The surrounding features look very electrical too. As for the idea that these are dormant volcanoes, I'd go for that, but only if the volcanoes are considered to be due to resistance heating where underground currents are in or outgoing. The 2 ridges in the second image might also have been drawn up as charge was escaping upwards along an underground current running fairly close to the surface?

[MattEU]

well spotted GaryN



egypts kamil meteorite crater and its hexagonal shape


kamil crater another example of hexagonal craters


hexagonal craters and the kamil meteorite or an electric universe discharge event?

amazing how may craters form hexagonal shapes. odd shaped rocks must just do that no matter what type of meteor they are, angle or speed of impact, if the planet/object has an atmosphere or not, what the body it impacts is made of, the value of G ...

[mharratsc]

amazing how may craters form hexagonal shapes. odd shaped rocks must just do that no matter what type of meteor they are, angle or speed of impact, if the planet/object has an atmosphere or not, what the body it impacts is made of, the value of G ...

Sarcasm? Here, on TB forums?? \




You guys are a witty lot... that's why I hang around here!

[MosaicDave]

I don't find any previous postings about this, so: An interesting and apparently recent crater has been recently discovered in Egypt.

Here's a Scientific Computing article about it:

http://www.scientificcomputing.com/news ... 92710.aspx

Some good photos on Flickr:

http://www.flickr.com/photos/34146259@N ... 440209687/

There are some unusual mounds and other geophysical features in the area. Some are visible in the Flickr photos. There's also a photo at the bottom of this page (http://www.mna.it/Kamil/) of the "Jebel Kamil", 65 km away. The form of the Jebel Kamil particularly suggests an electromagnetic genesis...

I wonder what other interesting aspects and features of this will be noticed by people on these forums...

--dc

[mharratsc]

. "This demonstrates that metallic meteorites having a mass on the order of 10-tons do not break up in the atmosphere, and instead explode when they reach the ground and produce a crater," says ESA's Dr Detlef Koschny, Head of Near Earth Objects segment for the SSA program.

This one crater is proof enough for ESA. Yep. I'm sure they're writing the Wiki article as we speak...

[nick c]

This demonstrates that metallic meteorites having a mass on the order of 10-tons do not break up in the atmosphere, and instead explode when they reach the ground and produce a crater," says ESA's Dr Detlef Koschny, Head of Near Earth Objects segment for the SSA program.

Evidently the 60 ton Hoba meteorite did not read this article, otherwise I am sure that it would have properly exploded upon impact.
http://www.flickr.com/photos/coda/191053386/

Nick

[GaryN]

They collected over 1000 kg of metallic meteorite fragments, including one 83-kg chunk thought to have split from the main meteorite body shortly before impact (it was found 200m away from the crater).

This demonstrates that metallic meteorites having a mass on the order of 10-tons do not break up in the atmosphere, and instead explode when they reach the ground and produce a crater,

So which is it?

Looks just like a hexagonal, rayed lunar crater from directly above.