Space rock impact site(s)

[Turtle]

I have new information to report! :( First, thanks to GoogleEarth Community Guide and new Hypography member Hill, we have a geologic overlay of Mexico. While rock type is not indicated, the suspect crater area is shown as extrusives of Tertiary age. Here's the overlay. >> Google Maps

 

Hill also took a screenshot of a low elevation view and marked the suspect crater rim; the image is attached to the GE Community thread. >> Google Earth Community: Impact crater in Chihuahua Mexico

 

I managed to turn on a GE overlay of meteorite finds and Crater del Tortuga Jorge is more conspicuous for lack of meteorites in its interior than it is for having a few on its rim. I also found some tourist photos from within the crater, and I'll see about linking them here.

 

The next tidbit is that I received a reply from impact physicist Mark Barlough today. :D He is cautiously optimistic and made several recommendations on what else to look for and who else to contact/notify. In particular, we need any and all remote sensing of the region we can find. I will follow up and report any progress.

 

Professor Barlough recommended this article as an example of finding an impact crater previously unknown using satellite imagery. >> Crater Discovery by El-Baz

 

That's a wrap, and keep looking down. :cup: :D

[freeztar]

That's very good news Turtl!

How did you find tourist photos from inside the crater? :(

From looking at the aerials, it looks as if the crater is pretty inaccessible.

 

Also, for remote sensing, I have ArcGIS at work if you need me to produce some maps of the area. :D

[Turtle]

That's very good news Turtl!

How did you find tourist photos from inside the crater? :cup:

From looking at the aerials, it looks as if the crater is pretty inaccessible.

 

Also, for remote sensing, I have ArcGIS at work if you need me to produce some maps of the area. ;)

 

I found the photos because they are linked to threads at GoogleEarth Community which puts the little blue "i" mark on everybody's GoogleEarth when they have GoogleEarth Community 'Layer' turned on. Here's the link to one of the posts with photo. Google Earth Community: Mineral del cobre Gnarly terrain dudes & dudettes! :D

 

Absolutely yes on any new type of mapping and/or geology-of-the-area info we can get. Prof. Boslough specifically mentioned looking for unusual breccias. Thanks for the help! :D

 

I E-mailed Fahruck El-Baz at Boston U. about the find and sent him the KML file and my screenshot of the NASA WorldWind map view. I think it's the most striking satellite imagery of the structure I have found yet. Here's to keeping our whistles wetted. :(

[Chacmool]

Well done, dear Turtle! Best wishes to our intrepid crater explorer (crateneer?). :hihi:

[freeztar]

Absolutely yes on any new type of mapping and/or geology-of-the-area info we can get. Prof. Boslough specifically mentioned looking for unusual breccias. Thanks for the help!

 

Well, it seems that the Mexico data that ESRI supplies with ArcGIS is very general and does not have a high level of detail. Furthermore, searches for GIS data in Mexico have turned up nothing. I know there has to be some good GIS data for Mexico out there, but I'm not finding it.

 

I encourage others to join in the search. You can download ArcExplorer for free which lets you load GIS data for viewing, but you can not manipulate or save.

 

That's all for now...

[Hill]

I found another feature posted over two years ago in Google Earth that has interesting possibilities. I can't link yet, but here are the coordinates >>>

15.8656°, 38.7746° in Eritrea. It lies near, but outside of the area of the Great Rift Valley volcanics. From time to time these features show up and are posted, but they get no response and quickly sink into the depths of the forums (many quite deservedly). But some like your find and this definitely stand out as real possibilities.

[Turtle]

I found another feature posted over two years ago in Google Earth that has interesting possibilities. I can't link yet, but here are the coordinates >>>

15.8656°, 38.7746° in Eritrea. It lies near, but outside of the area of the Great Rift Valley volcanics. From time to time these features show up and are posted, but they get no response and quickly sink into the depths of the forums (many quite deservedly). But some like your find and this definitely stand out as real possibilities.

 

Nice one Hill. I flew down and made a KML of the location for us. I see a GE Community mark there questioning whether the feature is volcanic or impact.

 

There is no debating however that we have quite a collection of circular features worth looking into. Because volcanism is always suspect, here is some info on a specific type of volcanic event called 'hydroclastic' that may create craters. Maars

 

Well, it seems that the Mexico data that ESRI supplies with ArcGIS is very general and does not have a high level of detail. Furthermore, searches for GIS data in Mexico have turned up nothing. I know there has to be some good GIS data for Mexico out there, but I'm not finding it.

 

 

I am quickly learning that without specific knowledge of the rock types we haven't much but our speculations. All in good time. :hihi: I haven't found anything using general search phrases such as 'geology of Mexico' etcetera. I agree there must be something. I wonder if there's anything 'findable' from oil exploration in the area? Interesting to note that one of the placemarks on GE is Copper Canyon as mineral deposits may help the case whether volcanic or impact...or both.

 

Well, back to the search & re-search. ;)

[Hill]

Originally posted by Turtle

I see a GE Community mark there questioning whether the feature is volcanic or impact.

This is quite common unfortunately. When GE was small, you had a chance to look at all posts arriving each day and everyone knew everyone. Now posts arrive so quickly there is no way to read them all and sort the wheat from the chaff. Many members post one or two things and are gone forever.;) We are in the very slow process - started way too late - of establishing moderated forums. I will take years imho. Anyway, thats how I came up with the latest crater as i was weeding through Nature and Geography posts for inclusion into the moderated forums.

 

As to maars, I recently became more familiar with them as I was replying to a member explaining why his placemark was not a meteor crater and was in fact a maar. No links allowed yet, but you can see a more complete treatment of the subject in the GEC Nature and Geography (Moderated) section. It should still be near the top of the 1st page.

[Turtle]

...As to maars, I recently became more familiar with them as I was replying to a member explaining why his placemark was not a meteor crater and was in fact a maar. No links allowed yet, but you can see a more complete treatment of the subject in the GEC Nature and Geography (Moderated) section. It should still be near the top of the 1st page.

 

I will look for it, and as it happens I was reading one such today. As part of some geology study years ago, I visited Hole in the Ground in Oregon and it's quite an impressive maar from the ground. :eek: Flying around to find it in GE today, I found it tagged with an impact title, and only in the associated thread did someone give the proper ID. :hihi:

 

Just spent some time web-surfing 'rock types in Mexico' and found some good descriptions of geology in other areas of Mexico. :doh: I did find this following source interesting; it is an assay type report looking for radioactive minerals in an area just East of suspect crater Tortuga. We can draw some general information from it in regards regional rock types. >> http://www.ejournal.unam.mx/revmexfis/no533/RMF005300305.pdf

 

That's a wrap. :ud: ;)

 

PS Found the Hole in the Ground mark, and Hill has it pegged! Google Earth Community: Hole in the Ground

It's this maar just East of Hole In The Gorund that is mis-ID'd in the title. >> Google Earth Community: 2 Craters directly across from each other!

 

Oooooo!!! Stop the presses!! Just 20 miles WSW of Hole in the Ground, check this potential impact!!! >> Google Earth Community: Enormous Meteor Crater

 

OK...I'm really done this time. ;)

[freeztar]

While flipping through my Astronomy book looking for potential questions for the unending Hypo science quiz, I stumbled across this delicious tidbit (from Universe. Fifth Edition. Kaufmann Freedman. New York. 2000.):

Virtually all [lunar] craters, both large and small, are the result of the Moon having been bombarded by meteoritic material. For this reason, they are also called impact craters. When this theory of the origin of craters was proposed by German astronomer Franz Gruithuisen in 1824, a major sticking point was the observation that nearly all craters are circular. If craters were merely gouged out by high-speed rocks, rocks striking the moon in any direction except straight downward would have created non-circular craters. A century after Gruithuisen, it was realized that meteoroids colliding with the Moon would have generated a shock wave in the lunar surface at the point of impact. Such a shock wave produces a circular crater no matter what the direction in which the meteoroid was moving. (In a similar way, the craters made by artillery shells are almost always circular.)

The shock wave from an impact can spread over an area much larger than the size of the meteoroid that generated the wave. Very large craters more than 100 km across, such as the crater Clavius..., were probably created by the impact of a fast-moving piece of rock only a few kilometers in radius. Many such large craters have a pronounced "central peak", a feature that is characteristic of a high-speed impact.

 

Nothing new to those initiated, but I found it a good description to deny "skipping stones" claims (if nothing else).

[Turtle]

While flipping through my Astronomy book looking for potential questions for the unending Hypo science quiz, I stumbled across this delicious tidbit (from Universe. Fifth Edition. Kaufmann Freedman. New York. 2000.):

A century after Gruithuisen, it was realized that meteoroids colliding with the Moon would have generated a shock wave in the lunar surface at the point of impact. Such a shock wave produces a circular crater no matter what the direction in which the meteoroid was moving. (In a similar way, the craters made by artillery shells are almost always circular.)

The shock wave from an impact can spread over an area much larger than the size of the meteoroid that generated the wave. Very large craters more than 100 km across, such as the crater Clavius..., were probably created by the impact of a fast-moving piece of rock only a few kilometers in radius. Many such large craters have a pronounced "central peak", a feature that is characteristic of a high-speed impact.

 

Nothing new to those initiated, but I found it a good description to deny "skipping stones" claims (if nothing else).

 

I got the initiation 'light'!:(:) I did not know about 'always circular regardless of angle because of shock wave' business. I do know about the raised central portion however. Called 'mascons', they form when a jet of super-heated gas & rock ejects from the center of the impact. This ejection occurs after the initial mushroomy shaped splash of material ejected at the edges, and the material that falls back out of the jet forms the mascon. I think Prof. Boslough showed experiments on the phenomina in one of the science shows I watched.

 

I went looking for remote sensing data and came up with nothing yet on the Mexico area, but a plethora of images and explanations of impacts taken by the ASTER program. I have quoted only 2 of the captions, but images #41 through #45 are high-res shots of impact craters. :shrug: :D :doh: :)

 

ASTER's Global View from Space

 

#41 The world's first Confirmed Impact Crater, Barringer Impact Crater, Arizona, USA / (N35 00/W111 00)

 

The impact crater, also called Meteor crater of approx. 1.3km of diameter and 145m depth is located in Colorado Plateau near Flagstaff, north of Arizona, USA. By the discovery of coesite and stishovite, minerals made when meteorite hits on earth ground, the crater was officially recognized as an impact crater for the first time in the world's history.

Since the crater was made in Permian sandstone and limestone layer in Permian, bulged rim typical to crater is prominent. The collision is estimated to be approx. 50 thousand years ago. Judging by the size, a meteorite of approx. 80m diameter and 2 million tons is considered to have hit the ground at a speed of 20km per second. Dry climate in the area helped to preserve the crater almost unchanged.

 

#42The world's largest size of impact crater, Vredefort Ring Structure, South Africa / (S27 10/E27 30)

 

Vredefort Ring Structure located 120km to southwest from Johannesburg, mid-north of South Africa. Although this ring structure is not officially confirmed to be an impact crater, it is believed to be one made approx. 2 billion years ago from the fact that minerals made by meteorite collision was found and based on other geological features. Its diameter is beyond 100km, which is the largest of all impact craters in the world. The image is focused on southwest part.

Basement rocks, mainly consists of granitic gneiss is in the center of Vredefort and new layers are distributed toward outside. As a unique character, basement rocks encircles the new layers all over again.

[Turtle]

...Just spent some time web-surfing 'rock types in Mexico' and found some good descriptions of geology in other areas of Mexico. :doh: I did find this following source interesting; it is an assay type report looking for radioactive minerals in an area just East of suspect crater Tortuga. We can draw some general information from it in regards regional rock types. >> http://www.ejournal.unam.mx/revmexfis/no533/RMF005300305.pdf

 

That's a wrap. :ud: :)

 

Turtle down! I went back to that link above & now I get an error message saying the file is damaged and not available!!??? Someone else want to give it a try?

 

I was going to cite the part where they said the Tertiary rock was sandstone. Looking on the WorldWind & GE view it is clear that the study area is a different rock type than the 'crater' is in and described as 'extrusive' in the GE overlay, but the East boundary of the crater borders the study area.

 

Any luck with that link? Any luck with other geology studies or maps? Who we gonna call!? :(:shrug::doh::):D

[freeztar]

Turtle down! I went back to that link above & now I get an error message saying the file is damaged and not available!!??? Someone else want to give it a try?

 

Sure, works fine here. :D

I was going to cite the part where they said the Tertiary rock was sandstone. Looking on the WorldWind & GE view it is clear that the study area is a different rock type than the 'crater' is in and described as 'extrusive' in the GE overlay, but the East boundary of the crater borders the study area.

 

This is rather puzzling because the article I'm looking at is entitled "Radioactive mineral samples from the northwest of Chihuahua City,Mexico". As Tortuga de Jorge is SW of Chi-city, I was left scratching my head. I skimmed the article and did a search for words such as "impact", "crater", "meteorite" and "sandstone" with no luck. :)

Any luck with other geology studies or maps? Who we gonna call!? :doh::shrug::doh::(:)

 

What I can do is post some pictures from my trip to Basaseachi, which is VERY close to the crater, and hopefully we can form a consensus on the geology from the photos. I'm much more of a mineralogist than a geologist, but from my armchair position, I would say that most of the rock around Basaseachi is basalt. Let me dig up the pics and I'll post them in a few...

[freeztar]

Ok, here's some tourist style pics from Basaseachi. I know I took many, many more of the geology of this area, but they are on my GF's computer and she claims that they are not (I've yet to search her drive obviously).

 

Pic 1: Notice the rough precipices behind us. Also, notice the rock to the right of me (I'm the dude :hihi:). This looks like volcanic stuff eh? Basalt?

 

Pic 2: More of the foreground rock, against the same type of background rock. You can tell where the foreground rock has been weathered due to water. The background rock looks geologically/relatively new, given the sharp, jagged peaks.

 

Hopefully this sheds some sort of light. :shrug:

[Turtle]

Sure, works fine here. :shrug:

 

This is rather puzzling because the article I'm looking at is entitled "Radioactive mineral samples from the northwest of Chihuahua City,Mexico". As Tortuga de Jorge is SW of Chi-city, I was left scratching my head. I skimmed the article and did a search for words such as "impact", "crater", "meteorite" and "sandstone" with no luck. :shrug:

 

working for me too now; thanks for loosening it. :hihi:so, before it vaporizes again, I see it only said

Alluvial deposits of 220 m thickness have been determined on a clay base of the Tertiary age [1]. ...

then ...

5. Conclusion

In accordance with the classification of the uranium deposits of the IAEA [10], San Marcos deposit is placed within the deposits type “Igneous with acid volcanic rock association”. The deposits are formed by hydrothermal activity from high to low temperatures. ...

 

Still doesn't clarify much for the crater, but it starts putting us in context. The more circular features I look at, no matter the cause, it is apparent Tortuga Jorge (:hyper:) is a standout on its size alone. If it's an impact, it's a really big one, if it's a volcano it's a really big one, if it's a salt dome it's a really big one, if it's a maar....well, you get the idea. :hihi: Prof. Boslough indicated that the idea of an impact triggering a volcanic eruption is still debated, but in his opinion it is more likely to have an eruption at the impact site than at the antipode for large impactors. He thinks it likely in these cases that the lava would cover the crater. (Mind you I am paraphrasing the remarks.)

 

What I can do is post some pictures from my trip to Basaseachi, which is VERY close to the crater, and hopefully we can form a consensus on the geology from the photos. I'm much more of a mineralogist than a geologist, but from my armchair position, I would say that most of the rock around Basaseachi is basalt. Let me dig up the pics and I'll post them in a few...

 

:camera: sweet! :hihi: let's rock. :shrug:

[freeztar]

The more circular features I look at, no matter the cause, it is apparent Tortuga Jorge (:shrug:) is a standout on its size alone. If it's an impact, it's a really big one, if it's a volcano it's a really big one, if it's a salt dome it's a really big one, if it's a maar....well, you get the idea. Prof. Boslough indicated that the idea of an impact triggering a volcanic eruption is still debated, but in his opinion it is more likely to have an eruption at the impact site than at the antipode for large impactors. He thinks it likely in these cases that the lava would cover the crater. (Mind you I am paraphrasing the remarks.)

 

Why paraphrase? Give us the nitty-gritty, if acceptable of course.

 

The last sentence casts shadows on GE-based crater findings, imho.

If lava covers the traces (which most often it can/does to an extent, as to be expected over large geological time periods), then how can we determine, orthophotographically, the distinction between volcanic/meteoric/salt-dome geographies?

 

So...I propose a field trip to Tortuga Jorge.

I can potentially secure us a base camp at no charge, complete with solar hot water and eco-friendly out-houses. There's also a bunkhouse that will fit 8-10 people max, but 4 people (non-coupled) very comfortably (not to mention 10 acres of land to set tent upon).

 

:hihi:

[Turtle]

Ok, here's some tourist style pics from Basaseachi. I know I took many, many more of the geology of this area, but they are on my GF's computer and she claims that they are not (I've yet to search her drive obviously).

 

Pic 1: Notice the rough precipices behind us. Also, notice the rock to the right of me (I'm the dude :hyper:). This looks like volcanic stuff eh? Basalt?

 

Pic 2: More of the foreground rock, against the same type of background rock. You can tell where the foreground rock has been weathered due to water. The background rock looks geologically/relatively new, given the sharp, jagged peaks.

 

Hopefully this sheds some sort of light.

 

Nice pic....of the rock I mean. :camera: It looks pretty light colored for basalt. Something andesitic?

 

Why paraphrase? Give us the nitty-gritty, if acceptable of course.

I didn't ask permission and it seemed inappropriate to quote without it. I'm pleasantly pleased to have received a response at all & I don't want to make myself the proverbial 3-day fish. :shrug: I plan to hasten slowly. :shrug:

 

The last sentence casts shadows on GE-based crater findings, imho.

If lava covers the traces (which most often it can/does to an extent, as to be expected over large geological time periods), then how can we determine, orthophotographically, the distinction between volcanic/meteoric/salt-dome geographies?

 

I don't have the impression that lava is more disposed to burying craters than other deposits. Granted determing the ages of the rocks is an important factor. The succesful pursuit & ID of impacts requires a multidisciplinary approach in my estimation. The satellite photography is proving its worth in identifying areas worth further investigation, and looking at the other structures may help refine our skills at ID'ing these critters. We are on the cutting edge -or is that ground floor?- of a resource previously unavailable to scientists let alone the general public.

 

One thought is that an impact may cause volcanism which then fills the crater, and then the crater & all the shocked minerals are preserved. Over time as the volcanics weather away, the preserved shocked minerals emerge & weather at a different rate leaving the crater outline visible.

 

So...I propose a field trip to Tortuga Jorge.

I can potentially secure us a base camp at no charge, complete with solar hot water and eco-friendly out-houses. There's also a bunkhouse that will fit 8-10 people max, but 4 people (non-coupled) very comfortably (not to mention 10 acres of land to set tent upon).

 

I'm not much for far travel these days, but your venture has my full moral support. :doh::hihi: I have given some though to an expedition, and given the terrain and a circumference to the 'crater' of around 200+ miles, I suspect it would take a month easy just to walk round it. Nonetheless, in the absence of finding the kind of rock data we need, an expedition is called for. I'll camp on it. :shrug: :hihi: