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Ceres Low-Altitude Mapping Orbit (LAMO)
Ken2
post Mar 23 2016, 12:39 AM
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QUOTE (atomoid @ Mar 22 2016, 01:38 PM) *
Looks almost like lava/mud flow at the edges of the PIA20350 where it appears to have pooled up and cooled as the level raised against the terrain barrier, forming the raised edge at the pool boundaries.


I agree, as if most of the deep floor of Occator was flooded (perhaps shortly after impact), and the light areas are the erupting / venting leftovers

Here's a closeup of one of the apparent flow edges.

Attached Image

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Gladstoner
post Mar 23 2016, 02:21 AM
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Some very preliminary observations and thoughts about Occator (some may have been mentioned already):

- The radial fractures at the center, surrounded by concentric fractures, seem to imply at least one cycle of uplift and subsidence.
- Could this be a variation of the process that produced Ahuna Mons?
- Most, if not all spots have a central crater-like structure.
- The dark areas on the west side of the main spot (with sharp boundaries) may be more recent talus slopes.
- The 'secondary' spots could be material that escaped from the central conduit. It could have moved along radial fractures.
- (Edit:) The spotty distribution of bright material in the smaller spots is interesting.
- The floor of Occator resembles a chunky stew. This could be the original impact melt.
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Gladstoner
post Mar 23 2016, 02:37 AM
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And then there is this dramatic radial fracture system:

Attached Image


Could something else be trying to push up?
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David Palmer
post Mar 23 2016, 11:19 AM
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Finally, with the lowest orbit of Dawn, the bright spots have been sufficiently resolved to understand their true nature.

Evidently the impact that created Occator Crater punched through into the subsurface ocean of Ceres, and created a weak spot that has henceforth served as a conduit for cryovolcanic outflows.

The main bright spot is inside of what appears to be a volcanic caldera, a depressed area with concentric cracks around (and inside) its perimeter, produced through the collapse of the roof of a "magma" chamber after its contents were extruded. And in the center of the caldera we have fresh dome-building, where slush is apparently pushing up (quite possibly in preparation for another significant eruption in the future), and this has caused radial cracks in the center (on the slopes of the dome) where the crust has been stretched.

This is extremely similar to the processes and landforms characterizing terrestrial volcanism, the only difference being that water is the "magma" in this case.

And just as with terrestrial volcanoes, we have outlying "cinder cones," apparently associated with fractures pointing radially away from the central caldera.

While it might be suggested that these features are simply a relic of ancient hydrothermal activity spawned by the heat of the original impact, the fact that this terrain is relatively free of craters is indicative of recent and even ongoing activity, plus the observations of apparent vapor above the floor of Occator Crater, in a diurnal cycle, indicate the same. Because unless there were ongoing outflows, any such volatiles would have sublimed away to nothing long ago.

The processes occurring here are similar to what I have suggested in my "artesian hydrant" model for the otherwise-inexplicable geology of Mars' Mt. Sharp. Namely that there are conduits connecting the surface of Mt. Sharp to an underground aquifer, and which are still occasionally active, and which I deem necessary to explain the relative youth of the channel and delta deposit to which Curiosity is currently headed (an aqueous-derived landform that has a relative lack of both cratering and erosional damage).

I would predict that Ceres will become an extremely hot target for exobiological research, with a huge push for a sample-return from Occator Crater, as any recent outflows might contain not only fossil organisms, but possible viable ones that could be revived, if an outflow were sufficiently fresh. And given the relatively small mass of Ceres, landing on it and taking off would be relatively easy with existing technology (its mass is only about 1/700 that of Mars and 1/90 that of Earth's moon).
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Daniele_bianchin...
post Mar 23 2016, 11:44 AM
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QUOTE (ZLD @ Mar 22 2016, 08:18 PM) *
Haven't used this process for a while but here is a blink animation I did a long while back for sub-pixeling an image of Occator in Survey Orbit.

The image is blinking between the original cropped view from Survey Orbit #16, the sub-pixeling version and finally Occator in LAMO. The final LAMO image has been skewed because the original image of SO was somewhat oblique in view.

[attachment=39131:Blink_2.gif]

I'm rather intrigured so many details seem to remain consistent while others seem present but shifted due to the nature of the original low resolution.

Compliments ZLD, very similar to original after many month!


Some impressions, but I could be wrong:

images 1. These structures resemble a cinder cones or volcano Domes...
Attached Image

images 2. These structures, SW out of the Occator crater, resemble a caldera...

Attached Image

images 3. These structures, "onion" shaped, they are located along a probably fracture.. The three (or more) craters in the bright material, are calderas? or impact craters that was fall on the material? Even they are located along a probably fracture...
Attached Image


images 4. An evident flux material visible NW of Occator crater, almost end of the image
Attached Image


Ps: Do you think that lines above 0ccator crater dome center are similar to the lines above of Ahuna Mons ?
Attached Image
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Daniele_bianchin...
post Mar 23 2016, 12:01 PM
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QUOTE (David Palmer @ Mar 23 2016, 12:19 PM) *
And just as with terrestrial volcanoes, we have outlying "cinder cones," apparently associated with fractures pointing radially away from the central caldera.

Hi David, While I was writing was not yet arrived your answer! then I was right? :-)

QUOTE (David Palmer @ Mar 23 2016, 12:19 PM) *
I would predict that Ceres will become an extremely hot target for exobiological research, with a huge push for a sample-return from Occator Crater, as any recent outflows might contain not only fossil organisms, but possible viable ones that could be revived, if an outflow were sufficiently fresh.

Even organisms? on a so 'small body and first of atmosphere?
You mean living organisms in a probable underground ocean? past or present?
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xflare
post Mar 23 2016, 02:51 PM
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It looks a bit like a lava dome to me minus the lava


Attached thumbnail(s)
Attached Image
 
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Bill Harris
post Mar 23 2016, 03:07 PM
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QUOTE (JohnVV @ Mar 21 2016, 11:12 PM) *
a few from LAMO 50


i am running into the "vacation slide show that never ends "

so people please point out spots on images YOU!!! want to see

I like those secondary clusters-- 3D at an oblique angle is so dramatic. LO-50 is located NW of Oxo caldera at N61 345E.

--Bill


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Xcalibrator
post Mar 23 2016, 03:49 PM
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This crater (volcanic? impact?) caught my eye as it's dark and surrounded by dark material. If it's from an impact, did it somehow create/lead to the fractures it intersects with, and does this provide info on when and how quickly these events occurred? If volcanic/vent, why is the outflow/vented material dark instead of light?
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jccwrt
post Mar 23 2016, 04:29 PM
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It looks like it's an impact crater coincidentally superimposed on the fracture system. If you look carefully the crater is almost tangential to the fracture. My guess is that it's just covered the bright salt deposits with darker crater floor material excavated from underneath. That's telling us that the salt deposits are relatively thin, because at most they're not as thick as the crater is deep. Considering the amount of dark ejecta, they're probably significantly less so.
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Ken2
post Mar 23 2016, 05:22 PM
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More observations of this amazing area (munching popcorn)...

Pict #1:

The circled areas look like smaller domes. The left one is reasonably high judging from the shadow. wish we could get in closer...

The square box looks like a vent flow - the lava flow seems to flow over the older vent/caldera/crater in the top middle of the box

Attached Image




Pict #2:

The main little white spot is hard to find the source of - I dimmed the pict and think it's a very large caldera, but hard to tell for sure.
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Ken2
post Mar 23 2016, 06:25 PM
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Just for easier visualization to see what was going on, I superimposed the nice color dome pict over the higher brightness large grayscale mosiac. It's a little ungainly, but I like the integrated view.

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alan
post Mar 23 2016, 07:12 PM
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Occator in 3D: https://twitter.com/Toy_Meister/status/712713108511436800
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Ken2
post Mar 24 2016, 10:42 PM
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A sense of scale compared to a terrestrial volcano (Mt St Helens in Washington) (1 mile = 1.6 km). Not sure if anyone has the exact height info yet.

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TheAnt
post Mar 27 2016, 11:23 AM
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QUOTE (Ken2 @ Mar 23 2016, 06:22 PM) *
I dimmed the pict and think it's a very large caldera, but hard to tell for sure.


Also I wondered when looking at the high resolution image, also the features left and right of your circle might be calderas.
I also noted the dark feature pointed out by Xcalibrator in a post below, and thought it to be an impact crater.
That is not surprising considering that the age of Occator now is estimated to be 80 million years.
(In fact I tended to think it was even younger with so few craters.)

Anyway, these bright spots now seem to be made by some kind of water vulcanism. Even so, this might still not be conclusive proof that there's a current ocean deep in Ceres interior.
Have anyone considered that the energy from the impact itself might have have created a near-surface pool of meltwater that lasted some ~10 kiloyears that would also explain the fractures and 'flux material seen here?
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