Author Topic: TLP Project - Deep Seated Fractures  (Read 9946 times)

Geoff

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TLP Project - Deep Seated Fractures
« on: August 23, 2010, 07:51:26 pm »
Background: See this thread for background on this project: Moon Zoo Challenge

Location:Site: Floor of Tycho crater.

Images: M114031031LE

Discovery: Anthony Cook

Description: Cracks like these are interesting, especially if there are few or no craters around them, especially if they are small isolated cracks with evidence of surface disturbances adjacent to the cracks.

Interest: Surface features that may have been freshly disturbed or contain a vent from which outgassing has occurred


The majority of Transient Lunar Phenomena (TLP) are covered in the other TLP Project threads on this board. This thread concentrates on the remaining TLPs, Deep Seated Fractures and “Atmospheric” Phenomena (if you think there are others not mentioned in these threads please PM one of the moderators).

Deep seated fractures can be found on some images from LROC but “Atmospheric” phenomena will probably not be found. Some images taken during the Apollo project had fuzziness along the horizon when it was expected that the horizon would be sharp-edged. This may have been caused by dust particles suspended above the lunar surface by electrostatic charging.

Deep Seated Fractures

The one feature which Anthony mentioned and which is not covered in the other TLP Project threads is deep seated fractures and he uses an example from the floor of Tycho crater:


Tycho Crater floor, from LROC image M114031031LE

Anthony also says about these fractures: Cracks like these are interesting, especially if there are few or no craters around them, especially if they are small isolated cracks with evidence of surface disturbances adjacent to the cracks.


One of the Moon Zoo users, ElisabethB (Els) has found something similar near Proclus crater:


ID: AMZ400381n
Latitude: 16.4221°
Longitude: 46.4991°
Sun Angle: -76.23°
Scale: 0.50 meters / pixel
Zoom Level: 3

Post any deep seated fractures you find in this thread.


”Atmospheric” Phenomena

Apollo 17 astronauts saw and sketched what they called “bands”, “streamers” and “twilight rays” which were visible just before lunar sunset or sunrise. These rays were also seen by astronauts on the Apollo 8, 10 and 15 missions.


from Nasa Media Library

On the side of the Moon in daylight, solar radiation knocks electrons out of atoms and molecules in the regolith causing a positive charge to build up which is sufficient to loft particles, 1 micron and smaller in size, above the surface. These particles can go up more than a kilometre.

Quote from: Timothy J. Stubbs, of the Laboratory for Extraterrestrial Physics at NASA's Goddard Space Flight Center
The Moon seems to have a tenuous atmosphere of moving dust particles. We use the word 'fountain' to evoke the idea of a drinking fountain: the arc of water coming out of the spout looks static, but we know the water molecules are in motion. In the same way, individual bits of moondust are constantly leaping up from and falling back to the Moon's surface, giving rise to a "dust atmosphere" that looks static but is composed of dust particles in constant motion.

It is believed that the dust on the night side of the Moon is negatively charged due to electrons from the solar wind flowing around the Moon onto the night side. So at the Moon’s terminator between the positively charged dust of the daylight side and the negatively charged dust of the night side, there could be flows of dust which may resemble auroras.

The four links below from NASA discuss various aspects of this phenomena:

Moon Fountains

Moon Dust in the Wind

Moon Storms

Lunar Transient Phenomena
« Last Edit: November 16, 2010, 10:10:24 pm by Geoff »

IreneAnt

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Re: TLP Project - Deep Seated Fractures
« Reply #1 on: August 23, 2010, 07:57:35 pm »
Thanks for that, Geoff. Very interesting.

Do you know why these cracks are called "deep seated" as opposed to just cracks? Does Anthony Cook have any ideas on how they are formed and why they aren't just cooling cracks? I'd love to see some more info on these....

Geoff

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Re: TLP Project - Deep Seated Fractures
« Reply #2 on: August 23, 2010, 08:09:38 pm »
Hi Irene

I don't know any more than is in the posting. I'll try and get more information from Tony but he sounds pretty busy at the moment so may be a while!

IreneAnt

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Re: TLP Project - Deep Seated Fractures
« Reply #3 on: August 23, 2010, 08:23:09 pm »
Thanks Geoff. I'll wait patiently.  ;)

Thomas J

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Re: TLP Project - Deep Seated Fractures
« Reply #4 on: August 23, 2010, 09:41:53 pm »
Me too  :)

Geoff

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Re: TLP Project - Deep Seated Fractures
« Reply #5 on: August 25, 2010, 07:20:19 am »
There is an article in Nature that mentions deep seated fractures in the summary but you need to pay or have a subscription to Nature to see the full article:

http://www.nature.com/nature/journal/v444/n7116/edsumm/e061109-06.html

Tom128

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Re: TLP Project - Deep Seated Fractures
« Reply #6 on: August 25, 2010, 02:29:05 pm »
Hi Geoff,

Here is an additional short excerpt from your very interesting article that they included in their link. I do not have a subscription:

"Here we report that patches of the lunar regolith in the Ina structure2, 3, 4, 5  were recently removed. The preservation state of relief, the number of superimposed small craters, and the ‘freshness’ (spectral maturity) of the regolith together indicate that features within this structure must be as young as 10 Myr, and perhaps are still forming today. We propose that these features result from recent, episodic out-gassing from deep within the Moon. Such out-gassing probably contributed to the radiogenic gases detected during past lunar missions. "

Though not a surface fracture, could this possibly be related to out gassing and not an impact in the Ina region?



# ID: AMZ1002y5n
# Latitude: 18.7891°
# Longitude: 5.25206°

Geoff

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Re: TLP Project - Deep Seated Fractures
« Reply #7 on: August 26, 2010, 12:31:30 pm »
I have a response from Tony Cook for the question raised by Irene:

Quote from: Dr Anthony Cook

Given that Irene is a planetary geologist by training, I think its probably safe to go with her conclusion that these maybe are just cooling cracks that formed on the Tycho floor impact melt. Anyway I used the term "deep" in a relative sense with respect to nearby topography.

The cracks on Tycho's floor were just to illustrate one example morphology of what we might be looking for, for evidence of outgassing. There are relatively few examples like this on the Moon, so whatever the cause they are worth cataloging, just in case they have some morphological aspects that might suggest outgassing in the present. And even if not, I'm sure that having a list of the locations of such cooling cracks would be useful to the planetary science community.

Also keep an eye open for brightness changes near edges of cracks or vents. If gas has vented out recently - depending upon factors such as volume, speed, duration, it might freshly disturb the soil. The Tycho cracks do not show such an effect, so this again leads to Irene's interpretation.

ElisabethB

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Re: TLP Project - Deep Seated Fractures
« Reply #8 on: August 26, 2010, 07:06:18 pm »

ID: AMZ100106n
Latitude: 24.168°
Longitude: 312.946°
Sun Angle: -70.15°
Scale: 1.43 meters / pixel
Zoom Level: 3

ElisabethB

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Re: TLP Project - Deep Seated Fractures
« Reply #9 on: August 26, 2010, 07:09:01 pm »

AMZ40037o8
Latitude: 16.3895°
Longitude: 46.5298°
Sun Angle: -76.23°

ElisabethB

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Re: TLP Project - Deep Seated Fractures
« Reply #10 on: August 26, 2010, 07:12:00 pm »

AMZ40043op
Latitude: 24.2923°
Longitude: 312.393°
Sun Angle: -75.86°

IreneAnt

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Re: TLP Project - Deep Seated Fractures
« Reply #11 on: August 27, 2010, 01:53:31 pm »
I have a response from Tony Cook for the question raised by Irene:

Quote from: Dr Anthony Cook

Given that Irene is a planetary geologist by training, I think its probably safe to go with her conclusion that these maybe are just cooling cracks that formed on the Tycho floor impact melt. Anyway I used the term "deep" in a relative sense with respect to nearby topography.

The cracks on Tycho's floor were just to illustrate one example morphology of what we might be looking for, for evidence of outgassing. There are relatively few examples like this on the Moon, so whatever the cause they are worth cataloging, just in case they have some morphological aspects that might suggest outgassing in the present. And even if not, I'm sure that having a list of the locations of such cooling cracks would be useful to the planetary science community.

Also keep an eye open for brightness changes near edges of cracks or vents. If gas has vented out recently - depending upon factors such as volume, speed, duration, it might freshly disturb the soil. The Tycho cracks do not show such an effect, so this again leads to Irene's interpretation.
Thank you very much Geoff for posting that, and thank you Tony for the very interesting response.

I just wanted to clarify, that I am by no means certain that these are cooling cracks. Rather, I was hoping to hear how cooling cracks might differ in appearance from "deep seated" cracks. The point about brightness changes at the edges due to regolith perturbations caused by passing gasses is really interesting. That would certainly be amazing to find.

And a catalog of  cooling cracks on the Moon would be very usefull. We could use those to identify locations of melt (impact and basalt, too possibly ;). Very cool!
« Last Edit: September 16, 2010, 03:47:17 am by IreneAnt »

ElisabethB

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Re: TLP Project - Deep Seated Fractures
« Reply #12 on: August 27, 2010, 04:09:16 pm »
so, if I understand things correctly : it is okay to post cooling cracks in this thread ?

AMZ40037yx
Latitude: 16.3724°
Longitude: 46.5052°
Sun Angle: -76.23°
Scale: 0.50 meters / pixel
Zoom Level: 3   

Geoff

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Re: TLP Project - Deep Seated Fractures
« Reply #13 on: September 14, 2010, 09:23:12 pm »
Not sure if these belong here but they look good:



from LRO strip: M106088433RC

Near King crater on the farside.
« Last Edit: November 16, 2010, 10:13:27 pm by Geoff »

jules

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Re: TLP Project - Deep Seated Fractures
« Reply #14 on: September 15, 2010, 10:33:58 am »
King crater region.