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Possible recent lunar volcanism
Bjorn Jonsson
post Oct 13 2014, 09:23 PM
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This is very interesting - and unexpected (at least to me):

http://lroc.sese.asu.edu/posts/818

Apparently there may be small features of volcanic origin on the Moon that are less than 100 million years old. The images are also very interesting - I would probably never have guessed that the image at the top was of lunar terrain.


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nprev
post Oct 13 2014, 09:45 PM
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I see gross similarities with some purported Mercurian volcanic features. Interesting indeed!


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Phil Stooke
post Oct 13 2014, 10:44 PM
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You saw it here first:

http://www.unmannedspaceflight.com/index.p...6070&st=375


(and many other posts in that thread if you follow it)

Sarah Braden was already well into documenting the features, I think, but had not published anything, when I did an LPSC poster on them.


Phil


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wildespace
post Oct 20 2018, 10:44 AM
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Ah, glad I found this thread, as I've just come across the "Ina" feature.

In an Apollo image of the area, it could be seen that the floor of Ina has a bluish tinge. Anyone know an explanation for this? What kind of minerals are giving it bluish hue?

AS17-152-23287 (auto-colour balanced from an unprocessed Flickr image)

Attached Image


Neal Spence combined the Apollo photo with high-rez b&w image from LRO (M175246029L).

Attached Image


Flickr: http://www.flickr.com/photos/terraform-mars/43614947480
Gigapan: http://www.gigapan.com/gigapans/211918


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Phil Stooke
post Oct 20 2018, 05:53 PM
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First, let me assure you there are no blue minerals here. The blue is not a true representation of the nature of the surface.

In general on atmosphereless bodies, freshly exposed material is brighter and 'bluer' (reflecting slightly more light from the blue end of the visible spectrum) and old material exposed to the space environment for a long time is darker and a bit redder. If you were there, looking at it, it would mostly look neutral but you might see a bit more red or brown in the darker areas and less red in the brighter areas.

Here we have a photo taken on film 40 years ago. We don't really know how well the film reproduced the actual color, or how it has changed in storage. It has been scanned - but is this a scan from the original negative or from a later print or negative? The scanner might not give a perfect reproduction of the source. Most important of all, the color balance process deliberately shifts the spectrum, and this is probably the most important source of a false blue tint.

Ina has a bright floor which has been exposed relatively recently in lunar terms - its floor might be 100 million years old, the dark regolith surface around it is much older and is space weathered - made darker and redder. The bright stuff is really fairly neutral in tone. Color balancing makes it look blue, but it is not.

Phil


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monty python
post Oct 21 2018, 05:46 AM
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It's kinda weird still. Are the light areas depressions or high areas, and how was it made?
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wildespace
post Oct 22 2018, 03:19 PM
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QUOTE (monty python @ Oct 21 2018, 06:46 AM) *
It's kinda weird still. Are the light areas depressions or high areas, and how was it made?

The brighter area is a depression, and darker areas are elevated. It can be really difficult getting your head around it.

BTW, here's an unprocessed scan of AS17-152-23287: http://www.flickr.com/photos/projectapollo...57659004120278/
This source mentions that the bluish colouration of Ina's floor is due to titanium-rich minerals: http://apollo.mem-tek.com/Ina/Ina.html
These document also confirm bluish tint as noted by Apollo astronauts, due to titanium-rich minerals:
http://apollo.mem-tek.com/Ina/PDF/1980-10%...%20-%201980.pdf
http://apollo.mem-tek.com/Ina/PDF/2011-10%...%20-%202499.pdf


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John Moore
post Oct 22 2018, 05:18 PM
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As to how Ina was made, and indeed other IMPs (Irregular Mare Patches - volcanic in nature) the most recent hypothesis suggests that the depression units are a left-over crust from a much larger lava lake
magma that developed deep down below within a dike/vent environment.

Essentially, the magmas produced a crust metres-thick composition in where numerous cracks formed during its cooling period, and that magmatic foamy deposits below (a mixture of magma with gases
created in the lava lake) squeezed through these cracks, producing the darker-looking, bulbous 'mounds' (as they are usually referred to) in the floor.

There are several other hypotheses as to IMP formation mechanisms. Surface features like craters, degradation and erosion effects, wall and mound slopes, regolith thickness, their surrounding mares etc.,
etc,. all have to be considered, too - each supporting the research posed in each hypothesis.

But the most important aspect about IMPs is the approximate age of them; where some hypotheses suggest that IMPs are young by millions of years, others suggest that they formed billions of years ago and
fit in with the generally-accepted theory that volcanism ended on the Moon round then. The age issue is very controversial today - because if they are young, then volcanism on the Moon ended later than
expected, and so thermal and magmatic models would have to be seriously revised.

A SmallSat concept mission, called IMPEL (Irregular Mare Patch Exploration Lander), could answer the question in the near future, particularly for Ina at which would be its intended target.

The various images out there of all IMPs proposed can be confusing - some views show them' flipped' or 'reversed' due to natural original images recorded by the Lunar Reconnaissance Orbiter (LRO) in its
orbit, some repeat odd-wise in a combination of both.

The forth-coming book, in early 2019, should set the record straight. All of the 70 so-far catalogued IMPs (with high-rez LROC images and lat/long coordinates) to date are included, as well as 40 additional
uncatalogued IMP features. LRO NAC numbers/references are also included with all, while a brief description on each and how to access them easily is included.

John Moore
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GoneToPlaid
post Feb 15 2019, 08:01 PM
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Hi everyone,

The colors shown by Neil Spence are mostly true, although overly enhanced in terms of saturation and contrast. The upshot is that the floor of the Ina caldera does have a distinctly blue color. Ina's blue hue is confirmed by the LRO's WAC camera, and is confirmed by even the most basic color balancing techniques which one would use for the Apollo 17 Hasselblad photographs of Ina. Amazingly, a couple of the best ground based photographs of the moon taken by amateur astronomers show Ina as only a few pixels in size, yet with a distinctly blue color.

The floor of the Ina caldera is comprised of approximately 10% titanium dioxide in the form of ilmenite. This explains the blue hue for Ina's lower units since TiO2 is a very blue mineral. The eastern areas of the floor exhibit very little heiligenschein in comparison to the mounds and to the surrounding terrain. This alone suggests that parts of the floor in the caldera are very young.

TiO2 map of Ina and the surrounding region:


Photograph AS17-152-23287:


Photograph AS17-152-23287 aligned and overlaid on top of LRO image M119815703LCRC. This is what Ina really looks like:


Photograph AS17-153-23577:


Photograph AS17-153-23578:


The large central mound is Agnes. Agnes is located on the eastern portion of the Ina caldera. Note the cratering on Agnes. Now note the general lack of any significant cratering on the foamy lava floor which surrounds Agnes. In fact, nearly all of the extremely tiny craters seen on the foamy lava floor actually contain a tiny boulder.


I hope that you enjoyed viewing these photos.

Best regards,

--GTP
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Phil Stooke
post Feb 23 2019, 08:37 PM
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I was just enjoying the very interesting post by GoneToPlaid when I realized I had said almost the opposite higher up the page. But GoneToPlaid is correct here.

I was commenting a bit hastily regarding a common situation in spectral analysis of airless bodies. Surfaces are often described as red or blue, or redder or bluer, and in many cases the 'bluer' material is neutral, but closer to the blue end of the spectrum than the redder material so it gets described as blue or bluer and processed as blue in images.

In this case I completely accept that the surface may in fact be blue.

Phil


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GoneToPlaid
post Feb 24 2019, 06:07 AM
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QUOTE (Phil Stooke @ Feb 23 2019, 12:37 PM) *
I was just enjoying the very interesting post by GoneToPlaid when I realized I had said almost the opposite higher up the page. But GoneToPlaid is correct here.

I was commenting a bit hastily regarding a common situation in spectral analysis of airless bodies. Surfaces are often described as red or blue, or redder or bluer, and in many cases the 'bluer' material is neutral, but closer to the blue end of the spectrum than the redder material so it gets described as blue or bluer and processed as blue in images.

In this case I completely accept that the surface may in fact be blue.

Phil


I am glad that you enjoyed my post. Ina is the really only obviously visually blue thing on the near side of the moon. Ina stood out to the Apollo 15 astronauts. Not sure, but I think that the transcripts will show that it was Worden who commented on Ina's extraordinarily blue color from orbit. Apollo 17 specifically photographed the Ina region in one of the CM orbital passes. Ina's blue hue has been photographed from Earth by what I consider to be two of the best amateur astronomer experts for lunar astrophotography, Michael Theusner and Michael Hunnekuhl. The blue hue in one of their best lunar photos is nearly identical to the hue in the Apollo photos which I presented.
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