Planet Four Talk

interesting lighter coloured regions in the center of the photo

  • A0097993A by A0097993A

    Hey guys, i noticed that there are numerous hilly or mountainous regions in this photo especially at the bottom right segment. I deduced this from the way the shadows are falling in this section of the photo. However, what do you guys think about the lighter brown segments featured prominently in the centre of the photo and the bottom left of the photo? I am unsure about what these are. The lighter brown areas seem to be at the peak of the mountainous regions to me.

    also there are some spiders in this photo

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  • CherylTsai by CherylTsai

    I agree, the less "dusted" regions seem to be of a higher elevation than the surrounding areas which could probably explain why it is of a lighter color. I thought it is good that you try to figure where the shadows are falling on and decipher the direction of the sunlight as it was mentioned in the January 2013 blogpost that the direction of the sunlight would affect out visual perspective of ridges and valleys.

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  • A0097993A by A0097993A

    Thanks for the reply! I was also leaning towards the viewpoint that this light brown coloration could be due to the surface elevation and the way the sunlight was falling. However, I think the colour gradient/differential from that of the bulk of the surface is very big. This may suggest either a very high elevation or perhaps maybe these spots were of a different composition or colour from the rest of the surfaces in the photo

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  • p.titchin by p.titchin

    Click on the 'view HiRISE link bottom right of the image and have a look at the HiRISE jpeg RGB colour strip. The image seems to be during a time of defrosting, and these lighter areas seem to be lighter frost lying in hollows and in the lee of elevations. It is easier to see looking at the 'bigger image' on the HiRISE than on the small cropped part of it that we classify. I could be totally wrong, but that is the way I see it.

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  • Kitharode by Kitharode moderator

    Rather than thinking of mountains and valleys in these images, you should think of bumps and channels. In the image here the difference between the highest and lowest point will only be a few metres (5 or 10?).

    I agree with Pete when he says that the bigger image helps us to understand these smaller images that we mark. 😃

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  • shawntan8390 by shawntan8390

    I'm not too sure too, but could these occur as a result of elevations and differential erosion on such elevations? Would it be possible?

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  • mschwamb by mschwamb scientist, translator

    Great discussion. It can definitely by tricky from the image alone to try and identify elevation. The lighter colored bits might be some type of frost or more fresh carbon dioxide ice according to Anya from the Science Team. She replied to a similar image here.

    Cheers,

    ~Meg

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